SRI 2024

26 Aug 2024, 14:30 → 30 Aug 2024, 18:00 Europe/Berlin

Registration as a peer reviewer of the SRI 2024 proceedings.

Monday 26 August

14:30 Registration and Visits to DESY and EuXFEL / Reception at DESY

Tuesday 27 August

08:00 Registration

Opening

Welcome address by Katharina Fegebank, Second Mayor of Hamburg and Senator for Science, Research and Equality
Welcome address by Karin Prien, State Minister of Education, Science and Culture of Schleswig-Holstein

Welcome address Helmut Dosch, chairmen of the DESY directorate

Welcome address Thomas Feurer, chairmen of the management board and managing director of the European XFEL GmbH

1 First light at the renewed Advanced Photon Source !

Following a year-long shutdown that began in April 2023, significant progress has been made in commissioning the new storage ring at the Advanced Photon Source. Multiple beamlines, including feature beamlines which form an integral part of the APS-U project, have entered technical commissioning and the facility as a whole is preparing to welcome back users. I will review activities at the APS in the last 18 months including
the storage ring removal and installation phases and will highlight the milestones achieved during the commissioning to date, on the storage ring and beamlines. I will also present some of the strategic opportunities that emerge from combining the renewed APS and the Aurora exascale computer at Argonne.

Speaker: Laurent Chapon (APS)

2 SPring8-II and beyond -Challenge to a high-performance greener light source

Advanced light sources are expected to accelerate the transition to a sustainable society through a variety of outcomes that contribute to innovation in industrial and living human infrastructure. In response to these demands, light sources themselves need to change to greener systems compromising higher performance with energy and material savings. Along this direction, we have gradually and continuously developed accelerator-based light sources at the SPring-8 site. This talk will start with the background of promoting greener light sources and outline several approaches achieving more environmentally friendly light sources. Then, the talk will overview a roadmap for the long-term upgrade of light source complex at the SPring-8 site and the SPring-8-II project, on-going greener high-performance upgrade of current SPring-8. The talk will also introduce the concept, targets and ongoing R&D of SACLA-II following the SPring-8-II project.

Speaker: Hitoshi Tanaka

10:45 Coffee Break

Mikrosymposium MS 1/1: Beamline Optics and Diagnostics: MS1/1

3 Achromatic and Apochromatic X-ray Lenses

Diffractive and refractive lenses are widely utilized in high-resolution X-ray microscopy with many applications in biology, energy and materials science. However, both diffractive and refractive X-ray optics suffer from strong chromatic aberration, i.e., they focus different wavelengths at different distances. As a result, many high-resolution X-ray analysis techniques are limited to utilizing monochromatic X-ray beams, meaning that a large portion of the X-ray flux is sacrificed. Achromatic and apochromatic lenses, capable of focusing multiple colours in a single point, have been long available for visible light. They are accomplished by combining individual lenses made from glass materials with different amounts of dispersion. In the X-ray regime, the realisation of achromatic and apochromatic lenses entails some unique challenges, mainly due to the inherent nature of the X-ray interaction with matter and the resulting intricacies in the X-ray optics fabrication. An achromatic X-ray lens can be realised by combining a divergent compound refractive lens (CRL) with a converging Fresnel zone plate (FZP) in close contact, as shown in Fig. 1(a). Such approach was theoretically proposed in the past [1—4], but it was only recently experimentally realised [5]. An alternative configuration, carefully choosing the separation distance between the two individual elements, results in apochromatic X-ray focusing [Fig. 1(b)], as theoretically suggested in [4] and experimentally demonstrated in [6]. The apochromatic case offers a correction over a significantly wider range of X-ray energies as qualitatively shown in
Fig. 1(c). Here, we discuss in detail the realization of achromatic and apochromatic X-ray focusing schemes [5,6]. The FZP was fabricated by electron-beam lithography and gold electroplating while the divergent CRL was produced by two-photon polymerization 3D printing. For the X-ray achromatic lens, the two elements can be now produced on the same membrane support [Fig. 1(d)]. We demonstrate the characterization of achromatic and apochromatic lenses by ptychography and scanning transmission X-ray microscopy and we present several proof-of-principle experiments for full-field transmission X-ray microscopy and for fluorescence scanning X-ray microscopy [Fig. 1(e)] realized at multiple synchrotron beamlines.

Speaker: Joan Vila-Comamala (Paul Scherrer Institut)

Picture1.png

4 Ultra-intense sub-10 nm focusing at a hard X-ray FELs

X-ray mirrors are essential for transporting and focusing X-rays in synchrotron radiation beamlines, thanks to their high reflectivity and minimal chromatic aberration. Recent progress in ultra-precise surface finishing and testing techniques [1-3] has enabled the creation of mirrors with accuracies reaching the 1-nm level. This has made it possible to achieve focusing down to 50-30 nm using Kirkpatrick–Baez (KB) geometry. However, sub-10 nm focusing at X-ray free-electron laser (XFEL) sources remains a significant challenge due to comatic aberration in KB geometry and unavoidable source pointing/angular jitter, which degrade the focusing conditions. Past methods used a secondary source slit to precisely define the source position, but this resulted in substantial photon loss, undermining the high-peak-brilliance characteristics of XFELs.
In this study, advanced KB (AKB) mirrors were utilized to achieve sub-10 nm XFEL beam focusing. These AKB mirrors, consisting of one-dimensional Wolter mirrors, reduce comatic aberration by satisfying Abbe’s sine condition, ensuring stable nanofocusing with greater tolerance to incident angle errors. Building on mirror characteristics and tuning strategies from previous developments in full-field imaging [4,5], we designed multilayer-coated advanced KB nanofocusing mirrors based on Wolter-type III geometry. The mirrors have been fabricated by a wavefront correction method [6,7] and achieved an accuracy of less than λ/15 in root-mean-square. Consequently, the ultra-intense XFEL sub-10 nm focusing system without the secondary source slits has been established at SACLA. The achieved focus, evaluated by the ptychography, indicated the spot size of 7 × 7 nm2 which corresponds to an XFEL intensity of 1.45 × 1022 W/cm2, representing the highest XFEL intensity ever recorded [8].
The presentation will showcase the AKB mirror development results, specifically the design and fabrication of sub-10 nm XFEL focusing mirrors, along with demonstrations of their reliable focusing performance.
References:
[1] K. Yamauchi et al., ”Figuring with subnanometer level accuracy by numerically controlled elastic emission machining”, Rev. Sci. Instrum., 73 4028–4033 (2003).
[2] K. Yamauchi et al., ”Microstitching interferometry for X-ray reflective optics”, Rev. Sci. Instrum., 74 2894–2898 (2003).
[3] H. Mimura et al., “Relative angle determinable stitching interferometry for hard x-ray reflective optics”, Rev. Sci. Instrum, 76 045102 (2005).
[4] J. Yamada et al., ”Compact full-field hard x-ray microscope based on advanced Kirkpatrick–Baez mirrors”, Optica, 7 367-370 (2020).
[5] J. Yamada et al., “Compact reflective imaging optics in hard X-ray region based on concave and convex mirrors”, Opt. Express, 27 3429-34378 (2019).
[6] S. Matsuyama et al., ”Nanofocusing of X-ray free-electron laser using wavefront-corrected multilayer focusing mirrors”, Sci. Rep., 8 17440 (2018).
[7] J. Yamada et al., ”X-Ray Single-Grating Interferometry for Wavefront Measurement and Correction of Hard X-Ray Nanofocusing Mirrors”, Sensors, 20 7356 (2020).
[8] J. Yamada et al., ”Extreme focusing of hard X-ray free-electron laser pulses enables 7 nm focus width and 1022 W cm−2 intensity”, Nat. Photon. 18 685-690 (2024).

Jumpei Yamada(1,2)
(1) Graduate School of Engineering, Osaka University, 2-1, Yamada-oka, Suita, Osaka, 565-0871, Japan.
(2) RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan.
yamada@prec.eng.osaka-u.ac.jp

Speaker: Jumpei Yamada (Osaka University & RIKEN SPring-8 Center)

5 Modular refractive X-ray Optics with Integrated Wavefront Manipulation

The correction of wavefront aberration [1] and manipulation of X-ray beam shapes [2] by refractive optics provides a toolbox to design and optimize X-ray beams. The foundation for these developments are micro-fabrication techniques like laser ablation and 3D printing in order to create freeform X-ray optics out of diamond or polymer. In combination with at-wavelength metrology methods these optical elements can be designed and validated. Recent advances in the fabrication of modular diamond X-ray optics enable the integration of wavefront-correcting freeform optics within the X-ray lens. This enables compact lens modules with integrated and pre-aligned aberration correction and/or beam shaping options. By combination of these modules a larger optical assembly can be realized. In this talk I will give an overview of these developments at DESY.

[1] F. Seiboth et al., “Hard X-ray wavefront correction via refractive phase plates made by additive and subtractive fabrication techniques,” Journal of Synchrotron Radiation 27(5), (2020).
[2] F. Seiboth et al., “Refractive hard x-ray vortex phase plates,” Opt. Lett. 44(18), 4622–4625 (2019).

Speaker: Frank Seiboth (FS-PETRA (PETRA III))

6 A Piezo-Modulated Active Grating for Selection of X-ray Pulses Separated by One Nanosecond

Synchrotron radiation is known for its stability, brilliance, and coherence, characterized by electron bunches circulating in the storage ring and generating pulsed radiation [1]. However, the MHz frequency range of these bunches often surpasses the temporal resolution required by numerous experiments. Addressing this discrepancy, we introduce a novel method for the temporal modulation of synchrotron radiation [2], suitable for time-resolved studies, developed and validated at the BESSY II synchrotron facility. This technique employs the selective modulation of X-ray pulses via Bragg reflection on a LiNbO3 piezoelectric crystal, equipped with comb-shaped electrodes of alternating polarity on its surface. The application of voltage to these electrodes induces a periodic deformation of the crystal through the converse piezoelectric effect, creating a dynamic diffraction grating for hard X-rays. This grating not only diverts the path of the X-rays but also modulates the beam intensity arriving at the experiment, offering a means to customize the temporal structure of X-ray pulses to specific experimental needs by electronically controlling the grating's amplitude.,

Our method allows a selective interaction with the synchrotron’s bunch pattern, permitting the rapid selection of individual X-ray pulses. This is achieved through a pulsed electrical source driving the grating modulation being fast enough to select pulses with a temporal spacing of 1 ns. This enables unparalleled adaptability in tailoring X-ray pulse time patterns for diverse research applications at synchrotron sources. Our current setup showcases an efficiency of 34% in beam intensity management, along the impressive 1 ns time-resolution realized for experiments, a metric limited by the speed of the driving electronics and independent of X-ray beam size.

Compared to existing methodologies [3-5], our solution stands out by its simplicity, flexible tailoring of the time structure of the X-ray pulses according to the actual needs of the user's experiments at the beamline's end station and its speed.

[1] Robert Schoenlein, Thomas Elsaesser, Karsten Holldack, Zhirong Huang, Henry Kapteyn, Margaret Murnane, and Michael Woerner. Recent advances in ultrafast x-ray sources. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 377(2145):20180384, 2019.
[2] S. Vadilonga, I. Zizak, D. Roshchupkin, E. Emelin, W. Leitenberger, M. Rössle, and A. Erko, "Piezo-modulated active grating for selecting X-ray pulses separated by one nanosecond," Opt. Express 29, 34962-34976 (2021)
[3] D. F. Förster, B. Lindenau, M. Leyendecker, F. Janssen, C. Winkler, F. O. Schumann, J. Kirschner, K. Holldack, and
A. Föhlisch, “Phase-locked mhz pulse selector for x-ray sources,” Opt. Lett. 40, 2265–2268 (2015).
[4] P. Chen, I. W. Jung, D. A. Walko, Z. Li, Y. Gao, G. K. Shenoy, D. López, and J. Wang, “Ultrafast photonic
micro-systems to manipulate hard x-rays at 300 picoseconds,” Nat. Commun. 10 (2019).
[5] S. Vadilonga, I. Zizak, D. Roshchupkin, A. Petsiuk, I. Dolbnya, K. Sawhney, and A. Erko, “Pulse picker for
synchrotron radiation driven by a surface acoustic wave,” Opt. Lett. 42, 1915–1918 (2017).

Speaker: Vadilonga Simone (Helmholt Zentrum berlin)

7 Adaptive Focal Plane Variation Using Alvarez X-ray Lens

Micro and nano-focusing are essential at beamlines at synchrotron light sources and X-ray free electron laser facilities for various X-ray techniques. The focal plane position of an X-ray optical element can be in error due to mispositioning or misalignment of the optical elements or chromatic aberrations in the case of refractive and diffractive optics. Often for in-situ experiments, the sample cannot be moved along the optical axis to the focal plane. The X-ray focal plane can be moved by Zoom X-ray Optics, but this requires multiple moveable optical elements and is difficult to implement and complicated to align.
We recently developed a varifocal X-ray lens based on the Alvarez lens concept which works in tandem with an X-ray focusing element allowing the focal plane to be adjusted [1]. In this paper, we present the working principle of the Alvarez X-ray lens (AXL) and its application for one and two-dimensional focal plane variations of X-ray focusing elements. Three AXLs were fabricated by 3D printing and were characterised along with an elliptical mirror and a compound refractive lens (CRL) at the B16 Test beamline at the Diamond Light Source. The AXL changed the focal plane of the mirror and CRL by a few mm on either side of the optics’ focal plane which is greater than the latter depth of focus. For the elliptical mirror, the coma aberration can be eliminated by combining the variation of focusing power with a small adjustment of the mirror. An AXL can be used to compensate for a CRL focus position change due to its chromatic aberration. AXL is small and easy to adapt to the existing optical layout as it does not deviate beam path, making it a useful device at beamlines where focus size, focal plane or astigmatism, and chromatic corrections are essential.

Reference:
1. Dhamgaye, V., Laundy, D., Khosroabadi, H., Moxham, T., Baldock, S., Fox, O. and Sawhney, K., Alvarez varifocal X-ray lens. Nature Communications, 14(1), 4582 (2023).

Speaker: Vishal Dhamgaye (Diamond Light Source)

8 SHADOW4: The Popular Ray Tracing Revived for Evolving Synchrotron Sources

For the synchrotron radiation community, “SHADOW” refers to a ray tracing program conceived by Franco Cerrina[1], widely used for the simulation of synchrotron radiation beamlines, recently in modern contexts within the OASYS environment [2].

Throughout three generations of synchrotron radiation sources, SHADOW helped in the design and upgrade of many beamlines, contributing to a deeper comprehension of pertinent issues surrounding synchrotron sources and reflecting, refracting and diffracting optics at photon energies covering the soft, tender and hard X-ray range. SHADOW has demonstrated its reliability during four decades of utilization, as shown in hundreds of user publications. The evolution of the SHADOW code and its interfaces have followed a cyclical pattern: after SHADOW2 [3], the interface ShadowVUI [4] was created, then SHADOW3 [5], followed by OASYS/ShadowOUI [6].

In light of both immediate and long-term considerations, a decision has been made to undertake a comprehensive overhaul of SHADOW, resulting in the development of an object-oriented package named SHADOW4, fully implemented in Python. Several compelling rationales have driven this initiative, among them being the imperative modernization of the Fortran-based SHADOW3 kernel. This modernization is crucial as the existing framework presents a potential bottleneck, imperiling the program’s sustainability in light of the evolving landscape of engineering and programming education. Python was the natural choice because the OASYS ecosystem is python-based and SHADOW4 and its new interface OASYS1-SHADOW4 are fully integrated into
OASYS. SHADOW4 uses modern and standard software engineering concepts that will permit a larger community of developers to help with new resources, tutorials, and documents. Python’s inherent portability ensures facile deployment of SHADOW4 across different platforms, including Windows, macOS, and Linux. The OASYS interface systematically generates SHADOW4 scripts, affording users the flexibility to customize and tailor calculations to their specifications, incorporating features such as variable scanning and the development of digital twins for integration with AI tools.

In summary, the advent of SHADOW4 guarantees the perpetuation of SHADOW’s
legacy, poised to serve as an indispensable resource for forthcoming generations of synchrotron light sources. We will present the new code, guaranteeing its functionality akin to previous versions, alongside its contemporary interface, and seamless integration into OASYS, and elucidate with examples the benefits compared to its predecessors.

References

[1] F. Cerrina. Ray tracing of recent VUV monochromator designs. SPIE Proceedings, 0503, Application, Theory, and Fabrication of Periodic Structures, Diffraction Gratings, and Moire Phenomena II, December 1984. https://doi.org/10.1117/12.944815

[2] Luca Rebuffi and Manuel Sanchez del Rio. OASYS (OrAnge SYnchrotron suite): an open-source graphical environment for x-ray virtual experiments. SPIE Proceedings, 10388, Advances in Computational Methods for X-Ray Optics IV, August 2017. https://doi.org/10.1117/12.2274263

[3] C. Welnak, P. Anderson, M. Khan, S. Singh, and F. Cerrina. Recent developments in SHADOW. Review of Scientific Instruments, 63 (1): 865–868, January 1992. https://doi.org/10.1063/1.1142630

[4] Manuel Sanchez del Rio and Roger Dejus. XOP 2.1 — a new version of the x-ray optics software toolkit. AIP Conference Proceedings, 705, 1:338–343, May 2004. https://doi.org/10.1063/1.1757913

[5] Manuel Sanchez del Rio, Niccolo Canestrari, Fan Jiang, and Franco Cerrina. SHADOW3: a new version of the synchrotron x-ray optics modelling package. Journal of Synchrotron Radiation, 18(5):708–716, July 2011. https://doi.org/10.1107/s0909049511026306

[6] Luca Rebuffi and Manuel Sanchez del Rio. ShadowOui: a new visual environment for x-ray optics and synchrotron beamline simulations. Journal of Synchrotron Radiation, 23(6):1357–1367, October 2016. https://doi.org/10.1107/s1600577516013837

Speaker: Manuel Sanchez del Rio (ESRF)

9 Accurate Ray Tracing of Bent Crystals in Bragg and Laue Geometries in Real Time with xrt and OpenCL

One of the major advantages of the xrt ray tracing and wave propagation package is its precise quantitative representation of the material properties of an optical element. xrt supports various kinds of X-ray optics including reflective (mirrors, capillaries), refractive (lenses), and dispersive (crystals, multilayers, zone plates and gratings). Complex amplitudes of reflectivity or transmittivity are calculated on the fly for a given set of direction, energy, and polarization, characteristic to an individual ray, thus eliminating the need for pre-calculated reflectivity maps and subsequent interpolation.
When it comes to the accurate calculation of the reflectivity of a bent crystal, either in Bragg or Laue geometry, there is no simple analytical solution. In the most general case, one would need to solve a system of ODEs called the Takagi-Taupin equations (TTE) numerically. A number of approximations have been developed over the years, including the Multi-Lamellar (for both Bragg and Laue cases) and the Penning-Polder (Laue only) models. Although not as precise as the TTE, they still pose a certain computational challenge.
In our work, we aimed to maintain the precision of the TTE method while increasing the performance to a level sufficient for real-time ray-tracing. We applied the adaptive Dormand-Prince method to calculate the amplitudes of forward-propagating and reflected waves inside a bent crystal and used the OpenCL framework to accelerate calculations. We rely on the pyTTE package to calculate a) elastic constants, required for integration, for a number of predefined crystals, such as Silicon, Germanium, Diamond, Alpha-Quartz, and some others, and b) the local orientation of the diffracting planes inside a crystal. The latter enables us to simulate phenomena such as monochromatic and polychromatic focusing, as well as sagittal focusing in asymmetrically cut Laue crystals. Performance-wise, we can process tens to hundreds of thousands of samples (rays) per second on a consumer-grade GPU.
The correctness of the calculations has been verified by a series of measurements performed at the BXDS beamline, Canadian Light Source, for a variety of asymmetrically cut Silicon crystals in Laue geometry.

Fig.1 Volumetric diffraction in asymmetrically cut Si[111] crystal with anticlastic bend, Laue geometry

Speaker: Konstantin Klementiev (MAX IV Laboratory)

volume_laue.jpg

Mikrosymposium MS 11/1: SR facilites: Updates and New Facilities: MS11/1

10 Status of the ALS-U project to create a soft x-ray diffraction limited light source

The ALS-U project to upgrade the Advanced Light Source to a multi bend achromat lattice received CD-3 approval in 2022 marking the start of the construction phase for the Storage Ring. Construction of the accumulator under a prior CD-3A authorization is already well advanced. ALS-U promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of magnitude brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. It is optimized to produce intense beams of soft x-rays, which offer spectroscopic contrast, nanometer-scale resolution, and broad temporal sensitivity. This paper presents the final design, prototype results as well as construction progress.

Speaker: Christoph Steier (Lawrence Berkeley National Laboratory)

ALS-U_Status_CSteier_SRI2024_20240827.pptx

11 Status of the PAL X-ray Facilities

Since the completion of PLS construction in 1994, Pohang Accelerator Laboratory has grown until it become one of the global top 5 facilities which operate 3rd generation synchrotron and X-ray FEL. We are now moving towards new challenges for continuous growth. In this talk, I will discuss about the current status and future direction of PLS-II.

Speaker: Jaehun Park

12 Status of the Diamond-II upgrade

Funding for the Diamond-II Project was announced in September 2023. Diamond-II is a major upgrade of the Diamond facility, covering an upgrade of the storage ring to a low emittance lattice, three new ‘flagship’ beamlines and extensive upgrades to many existing beamlines, a programme of development of core software, controls and computing and the construction of a new building adjacent to the Diamond storage ring building. The main features of the project and the current status will be described.

Speaker: Richard Walker (Diamond Light Source Ltd.)

13 The New Elettra 2.0 Diffraction Limited Storage Ring Facility

The new Elettra 2.0 diffraction limited storage ring facility

The third-generation Italian synchrotron radiation facility Elettra is located on the outskirts of Trieste. It has been serving the national and international scientific and industrial community since 1993, and was upgraded in 2007-2009. The radiation beams, collected and tailored by in-vacuum optical systems, propagate through beamlines to reach experimental stations where an array of different analytical and processing techniques is available. The resulting light, ten billion times brighter than that supplied by conventional sources, enables a broad spectrum of users from academic institutions and industry to gain access to advanced research capabilities and techniques and conduct state-of-the-art experiments in physics, chemistry, biology, life sciences, environmental science, medicine, forensic science, and cultural heritage.
The design of a new, more advanced source than the current Elettra began in 2014. These studies analyzed the possibility and possible cost of creating a new very low emittance storage ring, called Elettra 2.0, which could operate in the same Elettra tunnel using the current injection system, therefore minimizing and infrastructure costs. A wide range of technical solutions for the lattice of the new machine were examined, from 4-bend achromat to 10-bend achromat, and the cost-performance ratio led to the choice of an enhanced 6-bend achromat type structure, which would allow reaching an emittance of 212 pm-rad, at 2.4 eV, therefore about 47 times lower than the current emittance. At the same time, energy consumption would decrease by approximately 25%.
The Elettra 2.0 project [1][2][3] was approved by the Italian Government in 2017, with plans for the new machine to commence serving external users in 2027. The design phase lead to a final version of Elettra 2.0 a fully transversely coherent source up to 0.5 keV-photon energy, more than doubling the total average current and increasing brightness by more than two orders of magnitude as compared to the current source, and maintaining a diversified beamline portfolio to allow experiments across a broad spectrum of photon energies, from a few tens of eV to several tens of keV, while substantially increasing the number of beamlines operating in the hard-X-ray range. In perspective, the possibility of producing picosecond-long light pulses at a MHz repetition rate across multiple beamlines simultaneously, without interference to standard multi-bunch operation is also being considered. Another important aspect of Elettra 2.0 is the high degree of transverse coherence in both the horizontal and vertical directions, projected to improve by a factor of 60 at 1 keV as compared to the current source.
The Elettra 2.0 project includes the construction of new beamlines and an extensive upgrade of most of the existing beamlines to fully exploit the high brightness and high degree of coherence offered by the new source. Over 40% of the entire investment budget is allocated to this purpose. Following this program, Elettra 2.0 is poised to host up to 32 new and upgraded beamlines, with a comprehensive list detailed in the subsequent sections of this paper.

[1] E. Karantzoulis, Elettra 2.0 — The diffraction limited successor of Elettra, Nucl Instrum Methods Phys Res A. 880 (2018) 158–165. https://doi.org/10.1016/j.nima.2017.09.057.
[2] E. Karantzoulis, W. Barletta, Aspects of the Elettra 2.0 design, Nucl Instrum Methods Phys Res A. 927 (2019) 70–80. https://doi.org/10.1016/j.nima.2019.01.044.
[3] E. Karantzoulis et al., Elettra 2.0 Conceptual Design Report - ST/M-17/01, 2017.

Speaker: Luca Gregoratti (Elettra - Sincrotrone Trieste SCpA)

SRI2024.pdf

14 Overview of Hefei Advanced Light Facility

Hefei Advanced Light Facility (HALF) is the diffraction-limited synchrotron light source that is under construction now in Hefei, China.
The storage ring energy is 2.2 GeV, and the natural emittance is about 86pm.rad. Half will be focusing on the sciences conducted with VUV, soft x-ray and tender x-ray. With its high brilliance and coherence, new techniques will be enabled. In this talk, I will introduce the basic layout of the accelerator, scientific consideration and 10 beamlines in the first phase, and technical innovations.

Speaker: Donglai Feng (National synchrotron radiation laboratory, Univ. of Science and Technology of China)

15 BESSY II+ - Operando Capabilities for the Energy Transition

In 2023 BESSY II celebrated 25 years of successful user operation. With over 12.000 publications and 30.000 beamtime proposals from 58 countries continuous demand for this state-of-the-art light source is impressively demonstrated, not least because it mirrors the requirements of a changing user community, scientific needs and societal demands.
BESSY II+ is now the upgrade program to keep BESSY II in a top position for the next decade while bridging to its successor source BESSY III which is expected to start user operation in 2035. The ambitious holistic BESSY II+ project is subtiteled "Operando Capabilities for the Energy Transition”. Its focus is on understanding fundamental processes under real conditions, i.e. investigations of materials and systems “at work” (operando).
BESSY II+ is mutually stimulated by intense interaction with its user community and by longstanding partnerships, for example with the Max-Planck Society (e.g. flagship projects like EMIL and CatLab), and the PTB (metrology with synchrotron radiation). In this presentation the main goals of BESSY II+ will be discussed:
- Innovative experimental infrastructures
- Operando capabilities, sample environment, and integrated laboratory concepts
- Automation, digitalization and big data methods
- Novel accelerator instrumentation

Speaker: Antje Vollmer (Helmholtz Zentrum Berlin für Materialien und Energie HZB)

16 The Munich Compact Light Source – Lessons Learned at and Ongoing Upgrade of a Laboratory-Scale Synchrotron Facility with a User-Centered Operation Scheme

The possibility to generate low-divergence, high-flux, energy-tunable X-ray beams with a narrow energy bandwidth has long been limited to synchrotron radiation sources based on storage rings with hundreds of meters in circumference. In recent years, there has thus been a growing interest in inverse Compton scattering X-ray sources, as they also allow to generate such X-ray beams of high brilliance, yet with a machine footprint compatible with standard research laboratory settings. The Munich Compact Light Source (MuCLS) is a laboratory-scale synchrotron facility at the Technical University of Munich (TUM), which consists of a commercial inverse Compton X-ray source (Lyncean Technologies Inc., formerly of Fremont, USA) and a beamline with two endstations designed and constructed by TUM scientists [1,2].
In many other inverse Compton source projects (see, e.g., [2] and [3] for a list), the development of the source itself and its characterization, i.e., accelerator and laser physics, are major parts of the respective research programs. In contrast, they play only a minor role at the MuCLS where the research program has been explicitly focusing on applications of the X-ray beam in user experiments since the source’s installation in 2015. These applications are centered around, but not limited to, biomedical X-ray imaging [1].

In the first part of the contribution, the emphasis will be put on the lessons learned in more than nine years of user-centered operation. This will include some aspects of operating the inverse Compton source of the MuCLS day-to-day and efforts made to simplify this task. In addition, we will take a look at how an inverse Compton facility can meet the typical requirements and expectations users have concerning, e.g., source properties, source availability or access, also considering what they are used to from other X-ray sources. Furthermore, we will present some practical considerations for experiments, in particular for experiments in vivo.
In the second part of the contribution, the ongoing upgrade of the facility will be discussed. It will replace the two separate X-ray shielding enclosures along the single beamline [1] by a large shielded experimental area, resulting in a very high flexibility for future experiments.

References
[1] B. Günther et al., Journal of Synchrotron Radiation 27, 1395 (2020).
[2] E. Eggl et al., Journal of Synchrotron Radiation 23, 1137 (2016).
[3] K. E. Deitrick et al., Physical Review Accelerators and Beams 21, 080703 (2018).

Speaker: Martin Dierolf (1) Chair of Biomedical Physics, Department of Physics, TUM School of Natural Sciences, Technical University of Munich, Germany; 2) Munich Institute of Biomedical Engineering, Technical University of Munich, Germany)

Mikrosymposium 13/1: Technology Transfer

17 LEAPS-INNOV – A LEAPS pilot to foster open innovation for accelerator-based light sources in Europe

Performing research & development in a coordinated manner for the League of European Accelerator-Based Photon Sources (LEAPS, https://leaps-initiative.eu/) allows a more efficient use of resources and faster technology innovation. Facilitating partnership with industry underpins Europe’s technological sovereignty and realizes synergies across sectors. The project partners have initiated six collaborative technology work packages in the areas of source development, optics, detectors, sample environments and data science. The innovation pilot seeks to enhance partnership with industry through open innovation while kick-starting the implementation of the LEAPS Technology Roadmap.
LEAPS-INNOV explores different pathways for targeting industry as early-stage collaborators and suppliers, such as different procurement actions, joint workshops and forums, and knowledge and technology transfer measures. A special access program and dedicated workshops address industry, particularly SMEs, as users of the light sources to build a medium- to long-term perspective on enhanced industry engagement. Finally, LEAPS-INNOV includes a pilot activity bringing the light sources closer to user clusters and EU partnerships addressing societal challenges. In this way LEAPS-INNOV contributes to solving key technological challenges for over 50 light sources in Europe and worldwide.

Speaker: Elke Ploenjes-Palm (FS-FLASH-B (FLASH Photon Beamlines and Optics))

18 CelluXtreme - a unique technology for spinning strong continuous fibres from renewable, bio-based materials

Speaker: Karl Håkansson

19 The Nano Active Stabilization System - Results on the ESRF ID31 Beamline

Speaker: Thomas Dehaeze (ESRF)

20 KIT Superconducting Undulator Development - Story of a Successful Industrial Collaboration & Future Prospects

Undulators are X-ray sources widely used in synchrotron storage rings and free-electron laser (FEL) facilities. The development of undulators has a long tradition at KIT, dating back to the 1990s. With the commercial availability of low-temperature superconductors (LTS), a new type of undulator was born, the superconducting undulator (SCU). Compared to conventional cryogenic permanent magnet undulators (CMPUs), the SCU offers a higher maximum magnetic field on axis for the same magnetic geometry, i.e. gap and period length, and thus a higher tunability and/or brightness, which lead to a wider range of applications at modern synchrotron light sources.

In this context, the industrial cooperation between KIT and Bilfinger Nuclear & Energy Transition GmbH (formerly Babcock Noell GmbH) started more than 15 years ago. Since then, many projects have been successfully completed, leading to the production of the world's leading full-scale commercial superconducting undulators based on conduction cooling. Starting with the SCU15, the first of a kind installed superconducting undulator providing light to a beamline, followed by the SCU20 installed and still in operation at the Karlsruhe Research Accelerator (KARA). The successful realization of such new SCUs has required the simultaneous development of appropriate measurement facilities such as CASPER I & CASPER II. They allow local and integral measurement of the magnetic field profile, training of the undulator, optimisation of the (end) fields and analysis of the magnets, for which specific procedures and techniques have been developed within the collaboration. The fundamental research of this collaboration has resulted in a commercial product that is in demand and sold worldwide.

In addition, the measurement systems are constantly improved to remain at the cutting edge of technology. In parallel with direct improvements through new electronics or technologies, the focus is also on new concepts in fundamental research, taking into account the social challenges of sustainability and energy efficiency. This includes new cooling concepts for current leads, the use of new superconducting materials and the creation of new undulator designs.

In this contribution, we would like to give a general overview of what we have achieved in the field of superconducting undulator technology with regard to the products built within our partnership, as well as an outlook on our new prospects and investigations.

Speaker: Bennet Krasch (Karlsruhe Institute of Technology)

21 Shape-Tuning of Ultra-Shallow EUV-Diffraction Gratings Fabricated via Ion Irradiation

The operation of diffraction gratings in the EUV range frequently requires structures with heights in the range of a few nanometres. This is challenging to achieve via conventional etch processes, as those are often characterized by high rates of material removal. Hence, it is necessary to develop methods for fast and cost-efficient fabrication of such gratings. For this purpose, we utilize volume changes in solid materials after the irradiation with ions. So far, techniques relying on similar effects were limited to areas in the μm2 range [1]. We improve upon this by utilizing a broad ion source which allows us to achieve lateral scales of structured areas in the range of several tens of cm2.
During experiments, the whole sample is irradiated through a mask of photoresist directly attached to the sample surface. This mask was fabricated utilizing character projection electron beam lithography [2]. It shields part of the sample by decelerating impinging ions and enables the utilization of a broad ion beam. Compared to a direct write process with a focussed ion beam this reduces the writing time by at least two orders of magnitude.
In first systematic studies we investigated silicon irradiated with a broad beam of 30 keV helium ions for fluences ranging from 1016 to 1017 ions per cm2. Atomic force microscopy (AFM) was utilized to measure the dimensions of fabricated gratings. These gratings show sinusoidal profiles with heights in the range of 1 to 20 nm (fig. 1). Through variation of the ion species or angle of incidence during the irradiation, we were additionally able to tune the resulting structure shape from sinusoidal to rectangular (fig. 2). In conclusion, we present an easily controllable and reproducible technique to fabricate grating structures of various shapes with heights between 1 and 20 nm.

Speaker: Johannes Kaufmann (Friedrich-Schiller-Universität Jena)

SRI2024_JKaufmann_FSUJena.pdf

22 Specially Designed Cells Enabling In-Situ Observation of High-Current-Density Electrochemical Reactions with Multiple Spectroscopy Techniques

Nowadays, the overuse of fossil fuel has brought up the urgency to efficient energy conversion and green energy consumption, which gives significance to high-value-added electrochemical reactions, such as hydrogen evolution reaction (HER), oxygen evolution reaction (OER), carbon dioxide reduction reaction (CRR), nitrate reduction reaction (NO3RR), and C–N coupling reactions. The application prospects of the aforementioned electrochemical reactions are highly related to the performance of electrocatalysts under high current density (HCD). Therefore, the observation of HCD electrochemical reactions is of great significance. Unfortunately, the focus and signal-to-noise ratio of multiple spectroscopy techniques (XAFS, Raman, FT-IR, etc.) are severely challenged by violent bubble desorption under HCD conditions.

In this talk, first, we will introduce our work related to the structure-performance relationship of HCD NiMo-based electrocatalyst revealed by in-situ XAFS combined with XRD, and Raman (Figure 1. a-c)[1,2]. These catalyst families (NiMo-Fe, NiMo-Ru, NiMo-Pt, NiMo-Ir) exhibit high efficiency in various HCD electrochemical reactions, for example, HER, OER, and NO3RR, and have been applied in anion-exchange membrane electrolyzer (Figure 1. d)[3,4,5].

Second, we will introduce our latest progress in specially designed cells enabling in-situ characterization of high-current-density electrochemical reactions with multiple spectroscopy techniques. We have achieved the observation of various electrochemical reactions via a specially designed membrane-assembly-structure in-situ experimental cell. At present, it has been successfully applied to in-situ Raman as one of the important spectroscopy which gives high-quality results on the in-situ structural evolution of molybdate in solution under HCD of 1000 mA cm-2 (Figure 1. e). From this result, we observed a pH flipping phenomenon that had never been reported in in-situ testing under low current density. This also confirms the scientific importance of pursuing new research on HCD. The method can give other information closely related to the electrochemical reaction state such as electrocatalyst reconstruction (NiOOH in OER), reaction intermediates (NO2- n NO3RR), pH probe of micro-environment (HCO3-/CO32-), and H-O vibrations of water molecules. Recently, we also obtained high signal-to-noise ratio in-situ results under HCD through XAFS by this method, so it is universally applicable to multiple spectroscopy techniques.

This method can be further promoted to spectroscopy methods such as infrared SR-FTIR and XRS. Meanwhile, this technique will guide the electrochemical society to understand the HCD electrochemical processes further, and at the same time facilitate the industrial application of high-value-added reactions.

References
[1] Energy Environ. Sci. 2021, 14 (8), 4610- 4619
[2] J. Mater. Chem. A 2023, 11 (19), 10228-10238)
[3] Adv. Funct. Mater. 2021, 31 (21), 2010367
[4] Nat. Commun.,2023, 14, 3607.
[5] Chin. J. Catal, 2024, 56, 9-24.

Speaker: Xin Kang (Tsinghua university)

2024SRI figure.png

23 SyncLab – Combined Laboratory and Synchrotron Experiments for Optimal User Support and Sustainability

Many years to decades can pass from the time when a new analytical method is for the first time demonstrated until the time of its widespread use for application experiments. For a successful transfer of knowledge and technology, this period must be marked by methodological development, proof-of-concept projects in different fields as well as training of people.
In the field of X-rays, the use of brilliant synchrotron radiation in many cases enables first unique experiments. A wide dissemination of the new method is often only reached, when laboratory equipment is available. At the Berlin Laboratory for innovative X-ray technologies (BLiX) we therefore develop since 2009 instruments and methodology for the laboratory scale. Successful examples are the transfer of confocal micro-X-ray fluorescence (XRF) spectroscopy to a commercial system1, the operation of a transmission X-ray microscope2 or the development of a soft X-ray absorption spectrometer (XAS) enabling transient measurements on thin films3 and liquids.
SyncLab, a joint research group between BLiX and the Berlin synchrotron BESSY II, now aims at exploring the use of both - laboratory and synchrotron setups. We demonstrate the added value of utilizing laboratory setups for XRF and XAS before and after beamtimes concerning training, sample preparation and statistical analysis. We discuss the merits both for users of the techniques as well as the general benefit for technology transfer and sustainable use of instrumentation.

(1) Förste, F.; Bauer, L.; Heimler, K.; Hansel, B.; Vogt, C.; Kanngießer, B.; Mantouvalou, I. Quantification Routines for Full 3D Elemental Distributions of Homogeneous and Layered Samples Obtained with Laboratory Confocal Micro XRF Spectrometers. J. Anal. At. Spectrom. 2022, 37 (8), 1687–1695. https://doi.org/10.1039/D2JA00119E.
(2) Seim, C.; Baumann, J.; Legall, H.; Redlich, C.; Mantouvalou, I.; Blobel, G.; Stiel, H.; Kanngießer, B. Laboratory Full-Field Transmission x-Ray Microscopy. In Short-Wavelength Imaging and Spectroscopy Sources; SPIE, 2012; Vol. 8678, pp 61–70. https://doi.org/10.1117/12.2011142.
(3) Jonas, A.; Stiel, H.; Glöggler, L.; Dahm, D.; Dammer, K.; Kanngießer, B.; Mantouvalou, I. Towards Poisson Noise Limited Optical Pump Soft X-Ray Probe NEXAFS Spectroscopy Using a Laser-Produced Plasma Source. Opt. Express, OE 2019, 27 (25), 36524–36537. https://doi.org/10.1364/OE.27.036524.

Speaker: Prof. Birgit Kanngießer (Technische Universität Berlin)

Mikrosymposium 2/1: Beamline Innovations

24 High resolution X-ray spectroscopy of actinides at the KIT light source” for the session on “Beamline Innovations

High energy resolution X-ray absorption and emission spectroscopy techniques have become indispensable methods in actinide research.1,2 In the last 15 years, we have substantially advanced the experimental capabilities for high resolution X-ray spectroscopy of actinides at the KIT Light Source. This continuous effort has recently been expanded to include both additional beamlines as well as soft X-ray spectroscopy capabilities. One important motivation is conducting studies to obtain a deep understanding of the retention mechanisms of long-lived actinides and fission products in geochemical processes relevant for the long-term safety of a deep geological nuclear waste repository. Here, the X-ray spectroscopy techniques allow for in-depth insights into the actinide-ligand binding properties, which are still very controversially discussed. Our recent efforts also include the development of spectroscopic tools to probe metal-chelating ligand bond covalency of radiopharmaceuticals for the targeted alpha-treatment of tumors. We will discuss recent developments at the ACT experimental station of the CAT-ACT beamline3,4 and at the SUL-X and X-SPEC5 beamlines at the KIT Light Source.
One experimental technique, particularly powerful in differentiating oxidation states of actinides (An), is the An M4,5-edge high-energy resolution X-ray absorption near-edge structure (HR-XANES) method. This presentation highlights the latest technological developments at the ACT station, enabling HR-XANES for samples with low actinide loading (down to 1 ppm), in combination with a cryogenic sample environment that reduces beam-induced sample alterations.4,6 In addition, an in situ cell for studying interaction mechanisms of actinides with clay minerals at fixed redox conditions, in combination with tender (3-4 keV) X-ray spectroscopy at the actinide An M4,5 edges, will be presented. These experimental capabilities pave the way for examining coupled redox/solid-liquid interface reactions.6,7
Examples of applications of An M4,5 edge core-to-core and valence-to-core resonant inelastic X-ray scattering (CC-RIXS and VB-RIXS) for probing the electronic structure and binding properties of the actinide elements will be illustrated.1 An important new instrumental development is the possibility to record An M4 edge CC-RIXS at near-backscattering geometry, using the newly commissioned NEXT X-ray emission spectrometer at ACT or the recently installed single crystal analyzer X-ray emission spectrometer (Rowland circle geometry) at the SUL-X beamline.
The design and first experiments using a versatile chamber (the “Actinide Chamber”) with solid, liquid, and gas state cells for soft X-ray spectroscopy of actinides at the X-SPEC beamline at the KIT Light Source will also be illustrated. Furthermore, the ROXS (“Radionuclide materials Observed with soft X-ray Spectroscopy”) experimental station at the X-SPEC beamline, currently in the design phase, will be presented, focusing on the application of magnetic microcalorimeters for high energy resolution and high efficiency X-ray spectroscopy at the KIT Light Source.

References:
[1] Tonya Vitova et al. Nature Commun. 8, 16053 (2017); T. Vitova et al. Chem. Sci. 13 (37), 11038 (2022); [2] Ivan Pidchenko et al. , Environ. Sci. Technol. 51 (4), 2217 (2017); [3] A. Zimina et al. Rev Sci. Instrum. 88 (11), 113113 (2017); [4] Bianca Schacherl et al. J. of Synchrotron Rad. 29 (1),80 (2022); [5] L. Weinhardt et al. , J. of Synchrotron Rad. 28, 609 (2021); [6] Bianca Schacherl et al. Anal. Chim. Acta 1202, 339636 (2022); [7] B. Schacherl et al. Environ. Sci. Technol. 57 (30), 11185 (2023).

Speaker: Tonya Vitova (Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute of Technology (KIT))

Abstract_Vitova_SRI_2024.pdf

25 A combined IR and Soft-X-ray Beamline for Multimodal Interface Spectroscopy and Scattering

Liquid-vapor and liquid-solid interfaces drive numerous important processes in the environment and technology. Our understanding of the physical and chemical properties of liquid interfaces under realistic environmental and operating conditions on the molecular scale still falls short of what has been achieved for solid-vapor interfaces over the past decades. The main reason for this situation is the often greater difficulty in (1) the preparation of liquid interfaces (compared to solids) with controlled properties and (2) their investigation with high interface specificity under realistic conditions.
The Enhanced Liquid Interface Spectroscopy and Analysis (ELISA) beamline at BESSY-II aims to address these scientific and technological challenges through a concept that tailors both beamline optics and endstation infrastructure to the specific requirements of liquid interface science [1]. The beamline combines soft X-ray and infrared (IR) radiation, both originating from the storage ring, which are incident on the sample surface at the same time and the same location. While core-level spectroscopy, in particular ambient pressure X-ray photoelectron spectroscopy (APXPS), provides information on the elemental and chemical composition as well as potential gradients at the interface, reflection-absorption IR spectroscopy (RAIRS) offers complementary information about the orientation and bonding of molecules at the liquid-solid and liquid-vapor interface, expands the pressure range of in situ and operando experiments, and provides an excellent method to monitor possible radiation-induced damage to the interface and surrounding media in X-ray based spectroscopies.

The future ELISA beamline at BESSY-II, which is anticipated to commence operations at the end of 2025, will cover a wide energy range across two branches, both in the X-ray (30-2500 eV) and IR domain (10-10,000 cm-1). The low energy branch is dedicated to in situ studies of functional interfaces, in particular those with relevance for batteries and (photo)electrochemical devices, and cover the far UV range (including the Li K edge) up to the transition metal L edges. The high energy branch is dedicated to the investigation of liquid-vapor interfaces, for both fast flowing (e.g., jets and droplet trains) and static liquids (e.g., in a Langmuir trough).

[1] S. Vadilonga et al., Synchrotron Radiation News 35, 67-72 (2022).

Figure 1: The new ELISA beamline will enable simultaneous IR and X-ray-based investigations at liquid interfaces from the same sample location.

Speakers: Hendrik Bluhm, Simone Vadilonga (Helmholtz Zentrum Berlin)

Bluhm Vadilonga Fig 1.png

26 Why XAS Beamlines of the Future Should be Self Driving

Speaker: Oliver Mueller (SLAC National Accelerator Laboratory)

27 Oxygen-Free Pd/Ti Deposition Applied for Soft X-ray Beamline 12A in Photon Factory

Nonevaporable getter (NEG) is a functional material that is activated by heating under clean ultrahigh vacuum (UHV) conditions and then pumps residual reactive gases at temperatures lower than the activation. Conventional NEGs consist of alloys containing group 4 and 5 metal(s) in the periodic table such as Zr, V, and Ti. During activation, oxygen atoms on the surface oxide layers of the NEG diffuse into the bulk, leaving a reactive surface that is available for absorbing or adsorbing residual gasses such as H2 and CO. When NEG is deposited on the inner wall of a vacuum vessel, the vacuum vessel will evacuate the residual gases just by baking, and UHV can be maintained without electric power for several decades. Therefore, the development of NEGs will contribute to CO2 emission reduction and Sustainable Development Goals (SDGs). In 2001 C. Benvenuti et al. reported that TiZrV thin films deposited by DC magnetron sputtering can be activated by baking at 180 °C for 24 h [1]. TiZrV deposition was used with great success at CERN and is now adopted in accelerator facilities around the world. Recently we have developed a new NEG named oxygen-free Pd/Ti [2]. The initial pumping speeds of the oxygen-free Pd/Ti thin film after baking at 150 °C were estimated to be 3.2 L s–1 cm–2 for H2 and 7.6 L s–1 cm–2 for CO at room temperature [3]. The oxygen-free Pd/Ti deposition for vacuum chambers and components in soft X-ray beamlines of synchrotron radiation seems to be ideal because it can be partially activated by baking at 75 °C for 6 h [3], and its pumping speed does not decrease in the pressure region below 10–8 Pa. In addition, oxygen-free Pd/Ti deposition provides following advantages: 1) Residual hydrocarbon gas becomes CO and CO2 through the catalytic action of Pd and is pumped by a turbo molecular pump, thereby reducing carbon contamination of the optical elements, 2) degassing from the vacuum chamber or components can be reduced, 3) space is not required for the installation of a NEG pump, 4) a dedicated power supply and current feedthroughs are not required, 5) the vacuum chamber or components can be made smaller, and 6) safety and security can be ensured in the event of a power loss. In the present paper we will report on oxygen-free Pd/Ti deposition applied for a new soft X-ray beamline 12A in Photon Factory.

Speaker: Prof. Kazuhiko Mase (KEK)

SRI2024Fig_Mase.jpg

28 Quantum Material Spectroscopy Center at the Canadian Light Source

The Quantum Material Spectroscopy Center (QMSC) is a state-of-the art XUV and soft X-ray beamline facility at the Canadian Light Source. The QMSC operates within the photon energy range from 15 to 1200 eV and is intended for spin- and angle-resolved photoemission spectroscopy (SARPES and ARPES). A distinctive feature of the QMSC is the combination of two independent end stations dedicated to SARPES and ARPES experiments with a unique source consisting of a pair of 4 m long APPLE type undulators. The low- and high-energy undulators are installed side by side in a switch yard arrangement and provide the highest possible photon flux within this photon energy range. Complete polarization control in both linear and circular modes is available. Moreover, the quasi-periodic magnetic structure of the low-energy undulator results in optimized suppression of the higher order harmonics. The beamline is based on the Variable Line Spacing Plane Grating Monochromator (VLS PGM) design and delivers $10^{12}$ - $10^{13}$ photons/second at the experimental stations with a resolving power higher than $10^4$ over the full photon energy range.

Speaker: Sergey Gorovikov (Canadian Light Source Inc.)

29 The Dynamics Beamline (D-Line) at SSRF ——A New Beamline Combined with SR-IR and ED-XAS Techniques

Combined with synchrotron radiation infrared spectroscopy (SR-IR) and energy-dispersive X-ray absorption spectroscopy (ED-XAS)，Dynamics beamline (D-Line) is the first beamline in the world which have realized the concurrent measurements of ED-XAS and SR-IR at the same sample position in milliseconds time resolved scale. With the combination of two complemental techniques, D-Line is a powerful research platform to investigate the rapid structural changes of atomic, electron and molecular in complicated disorder systems such as physics, chemistry, materials science, extreme condition matters and so on. ED-XAS and SR-IR can also work as two independent techniques in two branch. The ED-XAS branch is also the first energy dispersive XAS beamline in China which uses a tapered undulator light source and can achieve about 2.5×10e12phs/s•300 eV BW@7.2 keV at the sample position. An exchangeable polychromator, working in Bragg reflection configuration or Laue transmission configuration, is used in different energy range in order to meet the requirements for beam size and energy resolution. The focused beam size is about 3.5 μm(H) × 21.5 μm(V) at Bragg mode, and the X-rays energy range is 5 to 25 keV. By 1D and 2D position sensitive detectors with frame rate up to 400KHz, tens of microseconds time resolution can be realized. Several distinctive techniques, such as concurrent measurement of in situ ED-XAS and IR, time resolved ED-XAS, high pressure ED-XAS, XMCD and pump–probe ED-XAS can be applied for different scientific goals.
Keywords: ED-XAS, SR-IR, Time-Resolved, D-Line, SSRF

Speaker: Dr Xiangjun Wei (SSRF)

30 The meV-resolved Inelastic X-ray Scattering Spectrometer at NSLS-II: Recent Performance Improvement and Science Capabilities Update

The ultrahigh resolution inelastic x-ray scattering (IXS) beamline at NSLS-II is designed to achieve sub-meV resolution at moderate energy of 9.1 keV for IXS experiments with high momentum resolution and high spectral contrast [1]. The key instrument is a novel spectrometer with a new type of analyzer optics based on post-sample collimation coupled with angular dispersive flat crystal optics in highly asymmetric Bragg reflections [2,3] to achieve comparable angular acceptance of the scattered photons as that of the spherical backscattering analyzer used in conventional meV-resolved IXS facilities operating at above 20 keV. As the first instrument of its kind, the spectrometer has demonstrated unique research capabilities in studying low-Q, THz dynamics in soft material systems with mesoscopic heterogeneity and complexity such as liquid crystals [4] and biomembranes [5]. Continuous effort in improving the performance, especially via the temperature control of high-resolution crystal optics with sub-mK stability, has led to a state-of-the-art energy resolution of less than 1.4 meV with sharp Gaussian-like tails and much enhanced counting efficiency in routine operation, making it a premier IXS spectrometer for studying dynamics of soft materials and further enabling the study of phonon dynamics in hard condensed matter systems including most quantum materials. In this presentation, an update on the operation and the latest performance of the spectrometer will be presented and discussed with recent examples.

• Work supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-SC0012704.
  † Corresponding author. E-mail: cai@bnl.gov
  ‡ Current address: Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.

[1] Y.Q. Cai, D.S. Coburn, A. Cunsolo, J.W. Keister, M.G. Honnicke, X.R. Huang, C.N. Kodituwakku, Y. Stetsko, A. Suvorov, N. Hiraoka, K.D. Tsuei, and H.C. Wille, “The Ultrahigh Resolution IXS Beamline of NSLS-II: Recent Advances and Scientific Opportunities”, Journal of Physics: Confer-ence Series 425, 202001 (2013); and references therein.
[2] A. Suvorov, D.S. Coburn, A. Cunsolo, J.W. Keister, M.H. Upton, and Y.Q. Cai,"Performance of a collimating L-shaped laterally graded
multilayer mirror for the IXS analyzer system at NSLS-II", J. Syn. Rad. 21, 473 (2014).
[3] Yu. Shvyd’ko, M. Lerhe, U. Kuetgens, H.D. Rueter, A. Alatas and J. Zhao, “X-Ray Bragg Dif-fraction in Asymmetric Backscattering Geometry”, Phys. Rev. Lett. 97, 235502 (2006).
[4] D. Bolmatov, M. Zhernenkov, L. Sharpnack, D.M. Agra-Kooijman, S. Kumar, A. Suvorov, R. Pin-dak, Y.Q. Cai, and A. Cunsolo, “Emergent Optical Phononic Modes upon Nanoscale Mesogenic Phase Transitions”, Nano Lett., 17, 3870 (2017).
[5] D. Bolmatov, D. Soloviov, M. Zhernenkov, D. Zav’yalov, E. Mamontov, A. Suvorov, Y.Q. Cai, and J. Katsaras, “Molecular Picture of the Transient Nature of Lipid Rafts”, Langmuir, 36, 4887 (2020).

Speaker: Yong Cai† (NSLS-II, Brookhaven National Laboratory)

Mikrosymposium 7/1: Imaging and Cohrerence Applications

31 XPCS in soft matter and biomolecular condensates at Cateretê beamline/Sirius

X-ray Photon Correlation Spectroscopy (XPCS) is a coherent X-ray scattering technique enabling to probe dynamics based on observations of fluctuations in the intensity of coherent X-ray speckles. XPCS has contributed to address important questions in soft matter and biomolecular condensates such as phase separation in protein solutions, colloidal microscopic organization during gelation, structure evolution of thermo-reversible gels, relaxation in polymer electrolytes, among others. The unique capabilities of XPCS to probe dynamics and structural evolution in non-equilibrium systems can answer fundamental questions about liquid-liquid phase separation of protein solution. XPCS can provide unique insights into biomolecular dynamics and condensate fluidity over the mesoscale particle size range. In this presentation I will show some recent results of biomolecular condensates and soft matter dynamics probed by XPCS at Cateretê Beamline, the coherent X-ray scattering beamline at the Brazilian Synchrotron Light National Laboratory, Sirius.

Speaker: Aline Ribeiro Passos (Brazilian Synchrotron Light National Laboratory)

32 Hard X-ray Omnidirectional Differential Phase and Dark-Field Imaging

Ever since the discovery of X-rays, tremendous efforts have been made to develop new imaging techniques for unlocking the hidden secrets of our world and enriching our understanding of it. X-ray differential phase contrast imaging, which measures the gradient of a sample’s phase shift, can reveal more detail in a weakly absorbing sample than conventional absorption contrast. However, normally only the gradient’s component in two mutually orthogonal directions is measurable. We demonstrate an approach to generate a new type of X-ray imaging mode, which called omnidirectional X-ray differential phase imaging.1 The proposed method enables us to detect the subtle phase changes in all directions of the imaging plane, which complements conventional X-ray imaging methods with information that they cannot provide. Importantly, the omnidirectional dark-field images can also be simultaneously retrieved for studying a wide range of complicated samples, particularly strongly ordered systems. The extract information will not only provide insights into the micro-architecture of materials, but also enrich our understanding the macroscopic behaviour. The presented technique could potentially open up numerous practical imaging applications in both biomedical research and materials science.

FIG. 1. (a) and (b) The retrieved average D_0 and amplitude D_1 of dark-field signal of a woodlouse sample. The gray color indicates that the normalized D_0 and D_1 changes from 0 (dark) to 1 (bright). (c) The constructed omni-directional dark-field, as rendered in an HSV color scheme. (d) and (e) The main orientation _A [0, 2] and normalized amplitude A_1 [0, 1] of differential phase. (f) The constructed omni-directional differential phase, as rendered in an HSV color scheme. (g) and (h), The calculated horizontal and vertical differential phase from A_1 and _A. The gradient varies from -3rad to 3rad (bright). (i) The reconstructed phase from (g) and (h), in which the phase ranges from -60 (dark) to 60rad(bright). The scale bar is 0.5mm.

Reference
1. H. Wang and K. Sawhney, Proc. Natl. Acad. Sci. U.S.A. 118, 2022319118 (2021).

Speaker: Hongchang Wang (Diamond Light Source)

Omni directional.png

33 Grazing-Incidence X-ray Holography for Visualizing Surface Mesostructures

Lensless X-ray coherent diffraction imaging (CDI), facilitated by ptychography, has emerged as a thriving field with promising applications in materials and biological sciences with a theoretical imaging resolution only limited by the X-ray wavelength. Most small-angle scattering based CDI methods use transmission geometry, which has limitations for studying nanostructures grown on opaque substrates or objects of interest comprising only surfaces or interfaces, including nanoelectronics, ultrathin-film quantum dots, photovoltaics, etc. To overcome the limitations, we developed coherent surface scattering imaging (CSSI) in grazing incidence reflection geometry that takes advantage of enhanced X-ray surface scattering and interference near total external reflection [1]. In grazing-incidence and reflection conditions, multiple scattering at the low incidence and/or scattering angles is an integral part of the coherent scattering from the surface features. We discovered that the dynamical or multibeam scattering promises 3D structural determination in a single view when the surface patterns cannot be effectively reconstructed by the conventional Fourier-transform approaches. To understand the problems, we developed a 3D finite-element-based multibeam-scattering analysis to decode the heterogeneous in-plane electric-field distribution required for faithfully reproducing the complex scattering features and 3D surface morphology, which is validated by experimental data quantitatively. This approach leads to the demonstration of hard-X-ray Lloyd’s mirror interference or multi-beam surface holography that dominates the grazing-angle scattering. A first-principles calculation of the single-view holographic images resolves the surface patterns’ 3D morphology with nm resolutions, which is critical for ultrafine nanocircuit metrology [2]. These approaches pave the way for single-shot 3D structure determination at the new-generation synchrotron sources, such as the upgraded APS, crucial for visualizing irreversible morphology-transforming physical and chemical processes in a time-resolved, in situ, or operando fashion. In this presentation, we will also discuss the newly built featured beamline, the dedicated CSSI beamline at 9-ID, at the APS.
[1] T. Sun et al., Nature Photonics 6, 586–590 (2012).
[2] M. Chu et al., Nature Commun. 14, 5795 (2023). DOI: 10.1038/s41467-023-39984-3.
The research and the use of the Advanced Photon Source (APS) 8-ID beamline was supported by the US DOE/SC/BES. The X-ray experiments were also carried out at DESY (a member of the Helmholtz Association HGF) PETRA-III P10.

Speaker: Jin Wang (Argonne National Laboratory)

34 Multibeam Ptychography: Nano Resolution at Macro Scale

X-ray ptychographic microscopy and computed tomography are indispensable non-invasive materials characterization methods for studying the internal structures of solids in many fields, from chemistry, catalysis, and material science to cultural heritage, with the improvement of X-ray sources, such as the upgrade of 3rd and construction of 4th generation synchrotrons, X-ray ptychography experienced explosive development and reached single-digit nm resolution. However, up to now, the ratio between the field of view and resolution for X-ray ptychography is in the range of 100 - 1000; thus, a compromise is needed since it is not typically feasible to scan large samples with high resolution, and on a short timescale; this directly affects the representativity of many studies. The acquisition speed in ptychography is ultimately limited by the amount of coherent photons in the incident beam. Thus, using an incoherent fraction of the beam can greatly increase the imaging speed. This approach is successfully used in multibeam ptychography (MBP), where multiple parallel beams irradiate the sample (Fig.1); the imaged area then is expanded by the number of beams used in irradiation. This can expand the domain of X-ray ptychography to larger samples or more rapid measurements compared to conventional single-beam imaging. MBP with hard X-rays has been previously demonstrated in a limited regime with up to three parallel beams and energies below 10 keV [1].
In the present work, we have developed and manufactured tailored lens tower arrays of 12 compound doubly concave lens towers [2] equipped with unique phase coding plates for creating diverse multiple parallel beams at energies above 13 keV. Recent advances in 3D laser nanolithography enabled achieving an unprecedented aspect ratio of the lens towers of more than 100:1. In the imaging experiments, we have demonstrated the application of MBP in various conditions and with different real-life samples: a Siemens star test pattern, a porous Ni/Al2O3 catalyst, a microchip (Fig.2), and gold nano-crystal clusters.
rucially, the performed reconstructions achieved the same spatial resolutions as conventional single beam ptychography reconstructions using similar experimental parameters. As our work demonstrates, high-resolution ptychographic imaging is no longer limited to small samples or with substantial subsampling of larger samples. These results open the perspective towards high-throughput tomographic imaging of thick samples with ptychography, which currently is not feasible due to the X-ray beam's very low coherent fraction at higher energies (> 20 keV).
References
[1] M. Lyubomirskiy, et al., Sci. Rep. 12, 6203 (2022)
[2] M. Lyubomirskiy, et al., Opt. Express 27(5) (2019)

Speaker: Mikhail Lyubomirskiy (FS-PETRA (PETRA III))

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Fig2.pdf

35 Advancements in X-ray speckle-based imaging across time and length scales

Speaker: Marie-Christine Zdora (Monash University)

36 Coherent Correlation Imaging for Resolving Fluctuating States of Matter

Fluctuations and stochastic processes are ubiquitous in nanometer-scale systems, especially in the presence of disorder. Real-space access to fluctuating states is impeded by a fundamental dilemma between spatial and temporal resolution. Averaging over an extended time period (or repetitions) is key for the majority of high-resolution imaging experiments. If, by lack of better knowledge, averaging is indiscriminate, it leads to a loss of temporal resolution and motion-blurred images.
We present coherent correlation imaging (CCI) [1] – a high-resolution, full-field imaging technique that realizes multi-shot, time-resolved imaging of stochastic processes. The key idea of CCI is the classification of Fourier-space coherent scattering images (Fig. 1a) – even at a low photon count where imaging is not possible. Contrast and spatial resolution emerge by averaging selectively over same-state frames. Temporal resolution down to the single frame acquisition time arises independently from an exceptionally low misclassification rate, which we achieve by combining a correlation-based similarity metric with powerful classification algorithm.
We apply CCI to study previously inaccessible magnetic fluctuations in a highly degenerate magnetic stripe domain state with nanometer-scale resolution. Our material is a Co-based chiral ferromagnetic multilayer with magnetic pinning low enough to exhibit stochastically recurring dynamics that resemble thermally-induced Barkhausen jumps near room temperature. CCI reconstructs high-resolution real-space images of all domain states by holographically aided phase retrieval [2, 3] and, unlike previous approaches, also tracks the time when these states occur. The spatiotemporal imaging reveals an intrinsic transition network between the states and unprecedented details of the magnetic pinning landscape (Fig. 1b) allowing us to explain the dynamics on a microscopic level.
CCI massively expands the potential of emerging high-coherence X-ray sources and paves the way for addressing large fundamental questions such as the contribution of pinning and topology in phase transitions and the role of spin and charge order fluctuations in high-temperature superconductivity.

[1] C. Klose et. al., Nature 614, 256-261 (2023)
[2] S. Zayko et al., Nat. Commun. 12, 6337 (2021).
[3] R. Battistelli, et. al., Optica, DOI 10.1364/OPTICA.505999

Figure 1: a, Principle of time-resolved coherent correlation imaging. Top: Sequence of camera frames showing Fourier-space coherent scattering patterns. Coherent correlation imaging classifies scattering frames by their underlying domain state, as indicated by the colors. Bottom: Real-space images reconstructed from an informed average of same-state frames. b, Map of attractive (blue dots) and repulsive (red areas) pinning sites. The background shows the position of the domain walls and their relative occurrence.

Speaker: Christopher Klose (Max-Born-Institut)

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37 Multiscale In Situ X-ray Laminography enabling the observation of damage formation in alloy sheets

Mechanical loading experiments of flat sheet materials allow investigating a broad range of stress triaxialities, including non-proportional loading. This is highly relevant for the understanding of fracture mechanisms under engineering-relevant conditions [1, 2, 3].

In this context, X-ray computed laminography (CL) [4] has proven to be a unique and powerful tool for the non-destructive 3D characterization of such specimens, which due to their non-cylindrical shape are not suited for the application of conventional computed tomography techniques. Here, CL offers a high and laterally isotropic resolution without the necessity of sample dissection, which is crucial for in situ studies. In particular, the screening of large sample areas followed by zooming into selected regions of interest is possible, providing access to a hierarchical view of the sample [1].

Here, we employ KIT’s complementary synchrotron CL instrumentation portfolio for a correlative study of the 3D strain damage interactions under varying stress conditions in alloy sheets on the micro- and nanoscale. The in situ CL measurements are complemented by macroscopic in situ surface microscopy-based strain measurements.

The obtained measurements allow us, studying the 3D strain damage interactions under varying stress conditions in alloy sheets on multiple scales. We combine microscale CL and macroscale surface microscopy to study non-proportional loading during so-called ‘load path change’ experiments from tension-to-shear (see Fig. 1) and shear-to-tension [2]. Subsequently, acquired 3D CL images permit to measure internal strain by means of projection digital image correlation [2] and the morphological development of damage and intermetallic particles. The measured strain fields agree with finite element simulation, confirming non-proportional loading with variable stress triaxialities during the loading experiments. Two types of damage features are observed: cracks in intermetallic particles and flat cracks in the aluminium matrix with sizes typical for grain-boundaries. The observed damage features are further studied by nanoscale CL [1], revealing their nanostructure and dependencies on the material’s grain structure.

Figure 1: Microscale snapshot of an in situ CL study of ductile fracture during a tension-to-shear load path change experiment. (a) Strain measured by in situ CL. (b) Corresponding simulated strain field. (c) 3D microstructure of damage within the investigated specimen measured by CL.

Speaker: Mathias Hurst (IPS/LAS, Karlsruhe Institute of Technology)

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13:30 Lunch Break

38 Lunch seminar: Applied Nanotools - Advancements in X-ray and EUV Diffractive Optics: Zone Plates, Gratings, and Resolution Targets - Two Decades of Progress and Future Prospects

39 Lunch seminar: Cosine: "High-Energy Optics for NewAthena and other applications"

14:30 Poster Session incl. Coffee

40 Scandium-45 nuclear-clock isomer driven by X-ray laser

Precise timekeeping is indispensable in everyday life, science, and technology. It relies on reference oscillators with stable frequencies. Atomic clocks -- the most precise time-measurement devices at present -- use spectrally very narrow resonant transitions between electronic states in atoms as their reference oscillators [1]. With the advent of hard x-ray FELs, the use of extremely narrow resonant transitions in atomic nuclei as reference oscillators for ultra-high-precision clocks is now within reach. Nuclear oscillators are naturally more stable and more resilient to external perturbations than their atomic counterparts.

Resonant excitation of an ultra-narrow transition in Scandium-45 nuclear isomer with hard x-rays became recently possible [2] due to the high spectral photon flux delivered by the European XFEL in self-seeded high-repetition-rate mode [3]. In this talk, the results of the Scandium-45 experiment [2] will be presented along with discussion of further developments of hard X-ray FELs required for ultra-high precision nuclear clocks in particular and for nuclear resonance studies in general.

[1] Ludlow, A. D. et al. Optical atomic clocks. Rev. Mod. Phys. 87, 637–701 (2015).
[2] Shvyd'ko, Yu. et al. Resonant x-ray excitation of the nuclear clock isomer 45Sc. Nature 622 (2023) 471.
[3] Liu, S. et al. Cascaded hard X-ray self-seeded free-electron laser at MHz-repetition-rate. Nature Photon. 17 (2023) 984–99/1.

Speaker: Yuri Shvyd'ko (Argonne National Laboratory)

16:15 Break

Mikrosymposium 1/2: Beamline Optics and Diagnostics

41 Development of Kirkpatrick-Baez Mirrors at NSLS-II

Introduction

Since 2018, we have been involved in R&D on X-ray mirror metrology and fabrication technologies. After five years of intense R&D efforts, we successfully integrated ion beam figuring (IBF) with advanced metrology, as seen in Fig. 1, demonstrating diffraction-limited hard X-ray mirror manufacturing capability (curved surfaces with up to a 0.6 mrad total slope) [1]. We have developed an IBF system, specifically for X-ray mirror fabrication. The 2D metrology feedback for IBF has been developed in parallel based on Fizeau stitching interferometry (FSI) and micro stitching interferometry (MSI), achieving sub-0.3 nm rms repeatability. Coupled with this, our multi-pitch nano surface profiler (MPNSP) for slope measurement with sub-30 nrad RMS facilitated cross-validation of metrology data across instruments with different principles. We also introduced optimization and control algorithms dedicated to sub-nm level IBF of optical surfaces. In the past two years, we confidently produced diffraction-limited KB mirrors and gratings for hard X-ray beamlines across the US.

Method and result

Figure 2 demonstrates an example of manufacturing a hard X-ray KB mirror for one beamline at NSLSII [1]. Starting from a spherical mirror shown in Fig. 2(a), the initial height and slope errors were 93.25 nm RMS, 3.12 μrad RMS, and 28.56 μrad RMS, respectively. After 15 cycles of IBF (about 5 hours), as shown in Fig. 2(b), the residual height and slope errors were reduced to 0.36 nm RMS, 0.15 μrad RMS, and 0.25 μrad RMS, respectively. These ultra-precision height and slope results were then confirmed by a cross-validation between our SI and NSP measurements. As shown in Fig. 2(c), the SI and MPNSP demonstrated extremely similar slope errors along the tangential direction, which proved the effectiveness of the proposed IBF-based KB mirror fabrication systems given in Fig. 1.

Reference

[1] Wang, T., Huang, L., Zhu, Y., Giorgio, S., Boccabella, P., Bouet, N., & Idir, M. (2023). Ion Beam Figuring System for Synchrotron X-Ray Mirrors Achieving Sub-0.2-µrad and Sub-0.5-nm Root Mean Square. Nanomanufacturing and Metrology, 6(1), 20.

Figure 1. In-house established optical fabrication and metrology solution.

Figure 2. (a) A KB mirror was fabricated from a spherical mirror. (b) The residual height and slope errors were reduced to < 0.5 nm RMS and < 0.16 μrad RMS, respectively. (c) The measurement results were cross-validated between our SI and NSP systems.

Speaker: Tianyi Wang (Brookhaven National Laboratory)

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42 High-Energy X-Ray Optics Development Leading to the APS HEXM Long Beamline

High-energy x-ray (40-140 keV) optics development at the Advanced Photon Source (APS) will be presented, encompassing monochromatization (for high-heat-load and high-resolution applications), focusing (with refractive optics such as tunable saw-tooth lenses and kinoforms), and full-field imaging. In addition to the experimental capabilities already enabled by these optics, such as various high-energy x-ray diffraction microscopies and element-specific resonant scattering at heavy-element K edges, their expected enhancement arising from the upgraded APS low-emittance storage ring and x-ray optics will be discussed, along with new coherence-exploiting techniques, within the context of the High-Energy X-Ray Microscope (HEXM) long beamline.

This research, conducted at the APS at Argonne, was supported by the U.S. Department of Energy, Office of Science, under Contract No. DEAC02-06CH11357.

Speaker: Sarvjit Shastri (Argonne National Laboratory)

43 X-ray Optical Delay Line at EuXFEL and Investigation of B4C Damage Threshold under Single-Shot Grazing Incident Conditions

At the European XFEL, two-color pump-probe experiments offer crucial insights into chemical reactions and molecular dynamics. High-intensity X-ray pulses with extremely high repetition rates enable researchers to observe sequential ionization. By adjusting the time delay between pump and probe pulses and tuning their wavelengths, researchers capture the sequence of events. To achieve this an x-ray optical delay line (ODL) in combination with a magnetic chicane inside of the undulator section is being developed. The ODL, consisting of four B4C coated silicon mirrors, provides a fixed delay of 200 fs, allowing new possibilities as the zero and negative delay between the two colors. The existing undulator set-up allows tuning of the X-ray photon energy in the range of 250-3000 eV, with single pulse energies up to several mJ.
Since the ODL mirrors are located very close to the source point of the radiation, the resulting small beam footprint on the mirrors is prone to cause severe damage to the mirror coating. In order to check the feasibility of the set-up, a dedicated experiment at the EuXFEL facility had been carried out at the SQS beamline. The objective of this investigation was to determine the damage threshold of B4C coating on silicon substrate when exposed to soft X-ray radiation at a grazing incidence angle of 9mrad. The corresponding damage threshold was determined to be 0.34 $\mu J/{\mu m}^2$.

Speaker: Marziyeh Sadat Tavakkoly (Eur.XFEL (European XFEL))

44 High Accuracy Simulations of Extreme Polarization Purity of a X-ray Beam for Brewster Crystal Diffraction

Xiaojiang Yu^a, Lingang Zhang^b, Liangliang Ji^b, Xiao Chi^c, A. T. S. Wee^c, Mark B H Breese^a,c, M.Sanchez del Rio^d

^aSingapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
^bState Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai 201800, China
^cDepartment of Physics, National University of Singapore, Singapore 117576, Singapore
^dEuropean Synchrotron Radiation Facility, 38000 Grenoble, France
*Correspondence e-mail: slsyxj@nus.edu.sg, srio@esrf.eu

Vacuum birefringence which is predicted by quantum electrodynamics (QED) has attracted more attention in recent years, due to advances in the development of powerful pump optical lasers (pump) and X-ray free electron lasers (XFEL) (probe) [1]. The head-on collision between the pump laser and probe XFEL will result in diffraction of X-rays and polarization-flipping for a trivial number of photons [2], which is around 10 billionth at the present power density level of optical laser and XFEL. Flipping changes the polarization of X-rays from linear to elliptical with ellipticity of around 1E-10 [3]. For experiments to verify such ellipticity, the linear polarization purity of the X-rays is required to be less than 1E-10. Several four-bouncing crystal monochromators (polarizers) working at the Brewster angle of 45 are proposed, which only deflect -polarization with -polarization being suppressed. However, the polarization purity is dependent on both the divergence and energy bandwidth of the X-ray beam impinging on the polarizer. The purity limit is given by an empirical formula which is estimated by the Gaussian divergence of the X-ray beam [4]. Nevertheless, the X-ray beam may slightly depart from a Gaussian profile due to beamline optical focusing and the bandwidth may not be accounted for properly in the formula, which may be not sufficient for extreme ellipticity. In this paper, we describe upgrades to the SHADOW [5,6] code to give high accuracy simulations for linear polarization of an X-ray beam after Brewster deflection. Treating the real divergence as well the bandwidth in the simulation has not previously been done. We present the simulation for a XFEL beamline optics with linear purity around 1E-11. It will give an alternative way to understand the linear purity in the future experiments.
References
1 W. Decking, et al, Nat. Photonics 2020 146 14(6), 391–397 (2020).
2 E.A. Mosman, et al,Phys. Rev. D 104(1), 1–11 (2021).
3 B. Shen, et al. Exploring Vacuum Birefringence Based on a 100 PW Laser and an X-Ray Free Electron Laser Beam, Plasma Phys. Control. Fusion 60, 044002 (2018).
4 K.S. Schulze, et al, APL Photonics 3(12), 126106–1 (2018).
5 M. Sanchez Del Rio, J. Synchrotron Radiat. 18(5), 708–716 (2011).
6 X.J. Yu, et al, J. Synchrotron Radiat. 29, 1157–1166 (2022).

Speaker: Dr Xiaojiang Yu (Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore)

45 Advancing Stability in X-Ray Laser Optics: Interferometric Solutions for SLAC's X-ray Cavity Project

The progressive development of X-ray laser sources requires high stability of optics that are distributed over large distances. X-ray laser amplifiers, which rely on the coherent superposition of circulating micron sized, femtosecond x-ray pulses in cavities, place demands on length and angular stability in the 100s nanometer and nanoradian range. They also need to interact with the gain medium, hence the similarly sized electron bunches from the linear accelerator in the undulator. Passive mounting and periodic adjustment can no longer cope with the dynamics of the ground motion, induced by environmental changes including temperature, water flow, and even tidal waves. This requires active control of the optics individually or in local clusters in relation to a global system, such as alignment to the undulators. We present how laser interferometers can serve as tools for measurement and active control of X-ray laser optics and present a design to stabilize the X-ray cavity in planning for SLAC's extension of LCLS.

Speaker: Sina Koehlenbeck (Stanford University)

SRI2024_Koehlenbeck_LCLSX_cavity_control.pdf

46 Fabrication and Characterization of Diamond X-ray Refractive Optics

The compound refractive lens (CRL) made of single crystalline diamond material for focusing X-ray beam at synchrotron radiation and X-ray free electron laser (XFEL), especially high power and high photon energy sources, has become a promotive topic during the last decade. Plenty of advantages such as non-toxic, higher refractive power, mechanical and radiation hardness, thermal conductivity, as well as optical purity allow the diamond as a promising alternative material rather than conventional Beryllium to be manufactured as refractive X-ray optics. This work presents the homemade stack of 10 bi-concave two-dimensional (2D) diamond CRLs in radius curvature of 50 μm fabricated by femtosecond pulse laser ablation. The shape quality of the individual lens was evaluated by extracting a paraboloid fit of its height profile measured by a confocal scanning laser microscope, which could reveal the surface error right after the fabrication process. Furthermore, the performance of the CRL stack was determined at beamline P06 at DESY via Ptychography by retrieving the beam profile around focus where a diffraction-limited focal spot of 250 nm was achieved (Fig. 1 (a)) and the accurate wavefront error at the exit of the CRL stack (Fig. 1 (b)). The results from these methods of metrology both show that our diamond CRL, whether as an individual lens or as a stack of 10 lenses, provides an improvement in lens shape and beam focus quality over the commercially available beryllium and diamond CRLs [1]. In addition, we can manufacture a corrective phase plate (PP) to compensate for the residual aberrations introduced by the CRL stack [2] (Fig. 1 (c)).
Figure 1 Evaluation results of the diamond CRL stack

Speaker: Wenxin Wang (FS-PETRA (PETRA III))

SRI2024.png

47 Undulator Models for Ray-Tracing Simulations

Undulators serve as the primary magnetic structures for generating synchrotron radiation in third and fourth-generation sources. The emitted radiation from undulators is intricate, featuring spectrum peaks at specific photon energies (resonances), and the
beam geometry is notably influenced by the photon wavefront and emittance of the storage ring. Various software tools exist for assessing undulator radiation characteristics. Ray-tracing packages, for instance, construct undulator sources by sampling rays
according to distributions prescribed by undulator theory.

In this work, we present the models and algorithms utilized for simulating undulators in the new SHADOW4 package. While SHADOW has included an undulator model [1] since its conception, certain neglected effects, inconsequential for second-generation synchrotron sources, have gained significance in modern low-emittance storage rings
and fourth-generation sources. Notably, the consideration of photon source size, encompassing diffraction limit effects, and the impact of electron energy spread in high harmonic undulator operation. The SHADOW4 undulator sources now boast a range of enhancements and novel features.

The "Gaussian undulator" application, for instance, generates a source with rays conforming to Gaussian distribution, approximating undulator distributions with varying degrees of accuracy. This has been found very useful when in a first phase or prototyping beamlines using undulators as sources. The introduction of SHADOW4[2], a refactored, and refurbished version of this popular ray-tracing code, has facilitated the reimplementation, refinement, rectification, and augmentation of undulator algorithms, enhancing simulation performance and accuracy.

Here we describe the methods and algorithms used in SHADOW4 for simulating undulator sources. We first summarize the most important results of the undulator theory used, with a detailed discussion of the Gaussian approximations for beam sizes and divergences. Then, the algorithms and ideas used for sampling the rays of the
undulator sources, in the Gaussian approximation and the full model, are described. Finally, some examples and discussion are presented.

References

[1] K Chapman, B Lai, F Cerrina, and J Viccaro. Modelling of undulator sources. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 283(1):88–99, 1989. https://doi.org/10.1016/0168-9002(89)91260-6

[2] M. Sanchez del Rio and L. Rebuffi. 40 years of shadow: Serving four generations of synchrotron facilities. Synchrotron Radiation News, 36(5):6–7, 2023. https://doi.org/10.1080/08940886.2023.2274745

Speaker: Juan Reyes Herrera (European Synchrotron (ESRF))

Mikrosymposium 11/2: SR facilites: Updates and New Facilities: MS11/2

48 Updates from SOLARIS National Synchrotron Radiation Centre

The SOLARIS synchrotron in Krakow is a third-generation synchrotron radiation source operating in the medium electron energy range. The first synchrotron light in SOLARIS was observed in 2016, while the first user experiments were performed in 2018. SOLARIS is expanding its activities, constantly developing experimental beamlines and complementary infrastructure such as cryo-electron microscopes. SOLARIS, the only synchrotron in Central-Eastern Europe, offers research opportunities for unique scientific projects in fundamental research and applied sciences. In the presentation, we will present the SOLARIS synchrotron project and available infrastructure, provide practical information on access to the infrastructure, and show examples of the research results obtained at the Centre by the Users.

Speaker: Jakub Szlachetko

49 Beam commissioning and user operation of NanoTerasu accelerator system

NanoTerasu is a medium-sized highly brilliant SX and Tender X-ray storage ring light source built on a green-field. The NanoTerasu accelerator system consists of a 3 GeV storage ring based on four bends achromat lattice with a circumference of 349 m and a 3 GeV linear injector accelerator with length of 110 m. The compact accelerator system contributed to significant cost reduction of construction and operation of NanoTerasu facility. The installation of the accelerator system started in Dec. 2021 and successfully finished by the end of May 2023. The commissioning of NanoTerasu accelerator system started in Apr. 2023 and the first electron beam store was achieved in Jun. 2023. The commissioning of insertion devices (IDs) and beam lines in experimental hall started in Sep. 2023 and Dec. 2023, respectively. The first user operation at NanoTerasu was performed from Apr. 9th to 21st ,2024 for 296 hours. The stored beam current was 160 mA at top-up mode with uniform 400 bunches. A typical lifetime during user operation was 10 hours with initial 10 IDs under operation. The horizontal beam emittance is close to 1.1 nm.rad monitored with an X-ray pinhole camera system. Seven beamlines were used for various user experiments such as an X-ray coherent imaging and SX spectroscopy. The other three beamlines were under commissioning during the user operation. The total scheduled user time in the fiscal 2024 is 3500 hours. In this talk, the commissioning and user operation of NanoTerasu accelerator system will be presented.

Speaker: Nobuyuki Nishimori (National Institutes for Quantum Science and Technology)

50 NSLS-II - The First Ten Years

National Synchrotron Light Source II (NSLS-II) is a 3 GeV synchrotron facility located on Long Island, New York, that saw its first light ten years ago in October 2014. Since then, NSLS-II has quickly ramped up its accelerator and beamline capabilities, with 400 mA of stored beam and 29 beamlines in user operations today, plus 4 beamlines under construction and additional beamlines in development. In fiscal year 2023, over 1800 researchers used NSLS-II to conduct their research in a wide-range of scientific disciplines.

As a scientific user facility, NSLS-II provides stable and intense photon beams from infrared to hard X-rays, experimental capabilities, and data infrastructure to enable multiscale, multimodal, high-resolution studies on diverse systems of materials. NSLS-II vision is to be a hub for the use of synchrotron light to solve the world’s most challenging problems and improve our lives for the future. This presentation will showcase a few select highlights and approaches to illustrate the progresses made in the past ten years, as well as our future development plan to further enhance our ability to serve the scientific community well into the next decade.

National Synchrotron Light Source II is a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704.

Qun Shen
National Synchrotron Light Source II (NSLS-II)
Brookhaven National Laboratory, Upton, NY 11973, USA

Speaker: Dr Qun Shen (Brookhaven National Laboratory, NSLS-II)

Shen NSLS2_update abstract for SRI2024.pdf

51 PETRA III Operational Performance and Availability in 2023

At DESY the Synchrotron Light Source PETRA III offers scientists outstanding opportunities for experiments with hard X-rays of exceptionally high brilliance since 2009. Parallel to operation with high availability, a comprehensive study program supports hardware and software developments for the forthcoming PETRA IV upgrade. Key aspects in 2023 were the development of commissioning tools and the installation of a prototype PETRA IV 500 MHz Higher Order Mode (HOM) damped cavity. In view of the campuswide infrastructure provisions expected in the next years in parallel to the ongoing beam operation at PETRA III, a series of vibration tests were conducted to assess the impact of anticipated construction activities on beam stability. This paper provides a detailed description of the operation in 2023, reviews the availability and fault statistics and gives an outlook to the next runs.

Speaker: Rainer Wanzenberg (MPE (PETRA))

PETRAIII_SRI2024.pdf

52 Operando Soft-Xray Spectroelectrochemistry at the MAX IV Laboratory HIPPIE Beamline

HIPPIE is a high-flux, high-resolution soft x-ray beamline at MAX IV Laboratory (Sweden) with a new branchline primarily dedicated for operando studies of electrochemical interfaces. Such experiments utilize the dip-and-pull method to form a thin liquid meniscus on the surface of the working electrode in a three-electrode cell with a liquid electrolyte solution. Both the liquid film itself and the electrode-electrolyte interface can then be probed using X-ray photoelectron spectroscopy (XPS) or X-ray absorption spectroscopy (XAS) whilst maintaining full electrochemical control. The technique can be used to probe oxidation state changes, chemical shifts, electronic structure and electrochemical potentials in-situ.

In this talk we will introduce the capablilties of the beamline and endstation, focusing on spectroelectrochemical XPS/XAS experiments. We will include examples of dip-and-pull experiments at HIPPIE spanning topics including photo-electrocatalysis, battery interfaces and metal corrosion. The discussion will outline the experimental realities and challenges that any potential new user of the dip-and-pull method should be aware of. Finally, will also provide an overview of other types of experiment that are possible with this new instrument.

The HIPPIE beamline operates in the 250-2000 eV range, providing access to the L absorption edges of many transition metals and the K edges of light elements. The dip-and-pull XPS experiments are realized with an ambient-pressure hemispherical electron analyzer allowing measurements in vapor pressures up to 25 mbar. XAS can be measured in several modes, including total and partial electron yield or total florescence yield. The system is compatible with aqueous electrolyte solutions as well as some organic solvents, including many of those common in batteries. An argon/nitrogen atmosphere glove box can be attached to the measurement chamber such that air sensitive materials can be studied. Typically foils or thin films are used for the working electrode. This apparatus therefore provides one of the most flexible platforms for electrochemical studies using soft-X-ray spectroscopy.

Speaker: Robert Temperton (MAX IV Laboratory)

53 HESEB Soft X-ray Beamline at SESAME: Commissioning, First User Experiments, and Future Prospects

The collaborative efforts between SESAME and a consortium of five Helmholtz Centers comprising DESY, FZJ, HZB, HZDR, and KIT have led to the successful design and installation of the Helmholtz-SESAME Beamline (HESEB), the first soft X-ray beamline at the SESAME synchrotron facility in the Middle East, Amman, Jordan. This initiative was funded by the Helmholtz Association over a four-year project cycle that commenced in January 2019. In February 2024, HESEB achieved another significant milestone by welcoming its first user groups. These groups focused their research efforts on various topics, including the investigation of metal-oxide-semiconductor thin films.

The HESEB soft X-ray beamline covers a photon energy range from about 90 eV to 1800 eV. An APPLE II type undulator (BESSYII/Model UE56) in addition to linearly polarized light produces circularly polarized light which is important for the magnetic material characterization. The Plane Grating Monochromator (PGM) has two different gratings, 400 and 1200 grooves/mm. At 400eV, the photon flux on the sample is 4.4x1012 photons/s and the energy resolution is 8500 (E/ΔE). The spot size of the beam on the sample is 240x25 µm2.

The compact UHV analysis chamber, attached to the end of the HESEB beamline, was designed for soft XAS techniques. A Bruker XFlash Silicon Drift for X-Ray Fluorescence (XRF) detection and a Keithley 6487 picoammeter for Total Electron Yield (TEY) monitoring are used for absorption measurements. The HESEB end station has a motorized manipulator, reproducible 1µm lateral resolution, 4 degrees of freedom, transfer motion on the x, y, z axes, and rotation around the y axis to change the sample orientation relative to the incident X-ray beam. The receptacle unit has 3 slots for a) cooling b) magnetization and c) heating. In the cooling slot, the sample can be cooled by liquid nitrogen. In the magnetic slot, an electromagnet was placed to produce a field of 160mT perpendicular to the sample. In the heating slot, a button-type resistance heater is used to heat the sample up to 800°C.

One unique property of the HESEB end station is that measurements can be done in He atmosphere up to 1atm. This ability is e.g. important for vacuum-sensitive samples in cultural heritage research and for studies of catalysts under near ambient pressure conditions. This is achieved by using an optical capillary placed in to photon pathway. It has a minimum hole diameter of 20µm and focuses the beam at 5 mm behind the capillary. Therefore it serves to maintain a high differential pressure allowing measurements in He atmosphere and by focusing the beam decreases the beam path length in the high-pressure He environment.

In brief, HESEB is SESAME's first Soft X-ray facility and its first undulator beamline which will notably expand SESAME's research capabilities. Equipped with a basic yet distinctive end station for absorption measurements, it has started to serve the user community.

Speaker: Mustafa Fatih Genisel (Synchrotron-light for Experimental Science and Applications in the Middle East, Allan, Jordan)

54 The Development of Technologies for Coherent Soft X-ray Science at the Advanced Light Source

The upgrade of the Advanced Light Source will provide an almost fully coherent soft x-ray beam to the
users, increasing the ALS brightness by 100x. Such a beam places extraordinary demands on every
beamline optical element. To maintain the beam’s coherence and wavefront properties in the presence of
high power loads, mechanical drift, and manufacturing errors, we have developed a suite of technologies
to monitor, preserve, and correct the wavefront dynamically, to ensure optimal performance in routine
operation.
We will present recent results on cryo-cooled mirrors [1], where our highest-power mirrors will be cryocooled
silicon to reach the 125K zero-point of thermal expansion, and be supported from one side in a
unique, cantilevered design. To enable continuous monitoring of the beam quality, we have developed a
fast, intermittent, wavefront sensor [2] based on shearing interferometer placed after the final focusing
mirror. The device uses a binary amplitude reflection grating used at glancing incidence in a conical
geometry. To compensate for eventual aberrations, each new beamline design includes a pre-figured
adaptive x-ray optic to correct wavefront errors and restore optimal beam properties. We have studied the
dynamic behavior of piezo-bimorph adaptive mirrors, and apply machine learning to overcome hysteresis
and creep [3]. To ensure diffraction-limited performance during regular user operation, we recently
deployed an automated alignment method for the whole photon transport system based on bayesian
optimization [4]. We will also present our work on the design and simulation of high-coherent-flux
beamlines, including efforts toward the creation of effective digital twins. And finally, we will present some
potential applications of wavefront engineering.
[1] Experimental testing of a prototype cantilevered liquid-nitrogen-cooled silicon mirror
G. Cutler, D. Cocco, B. Bentley, M. Cervantes, P. Chavez, J. Chrzan, S. DiMaggio, R. Hussey, J.
Ilmberger, J. Lindsay, E. Lizotte, K. McCombs, S. Morton, G. Paulovits, K. Pearson, C. Redding, N.
Smith, K. Tokunaga, D. Zehm, E. DiMasi and H. Padmore Journal of Synchrotron Radiation 30, 1 (2023)
https://doi.org/10.1107/S1600577522010700
[2] X-ray wavefront sensor development at the Advanced Light Source
K. A Goldberg, A. Wojdyla, D. Bryant, X. Shi, L. Rebuffi, M. Frith, M. Highland, L. Assoufid, Y. Ichii, T.
Inoue, K. Yamauchi; Proceedings of SPIE 12695, Advances in Metrology for X-Ray and EUV Optics X;
126950B (2023) https://doi.org/10.1117/12.2679136
[3] Data-driven modeling and control of an X-ray bimorph adaptive mirror
G. Gunjala, A. Wojdyla, K. A. Goldberg, Z. Qiao, X. Shi, L. Assoufid and L. Waller;
J. Synchrotron Rad. (2023). 30, 57-64 https://doi.org/10.1107/S1600577522011080
[4] Latent Bayesian optimization for the autonomous alignment of synchrotron beamlines
T. W. Morris, Y. Du, M. Fedurin, A. C. Giles, P. Moeller, B. Nash, M. Rakitin, B. Romasky, A. L. Walter, N.
Wilson, A. Wojdyla; Proceedings of SPIE 12697, Advances in Computational Methods for X-Ray Optics
VI; 126970B (2023) https://doi.org/10.1117/12.2677895

Speaker: Antoine Islegen-Wojdyla (ALS Lawrence Berkeley National Laboratory)

Mikrosymposium 2/2: Beamline Innovations

55 The Structural Materials Beamline at CHESS: An emerging facility for High Energy Monochromatic and White-beam Diffraction

In 2019, the Air Force Research Laboratory established the Materials Solutions Network at CHESS (MSN-C): a sub-facility of the Cornell High Energy Synchrotron Source (CHESS) created to provide critical measurements and research products to U.S. Department of Defense (DoD) researchers and defense Original Equipment Manufacturers (OEMs). The Structural Materials Beamline (SMB) is one of two beamlines comprising MSN-C. It is optimized to characterize structural (primarily metallic) materials across a broad range of length- and time- scales for the purpose of investigating the impact of conventional and emerging alloy/material design and manufacturing/processing pathways through both in situ and ex situ experimental campaigns. Specialized instrumentation and methods have been developed to characterize the real-time thermal-mechanical response of alloys and to map residual stress fields in metallic components (e.g. titanium fan blades from jet engines) through diffraction-based techniques.

SMB operates in two modalities: white beam (50-200keV) for energy dispersive diffraction, and a high-energy monochromatic beam (40-90keV) for transmission powder diffraction and high energy diffraction microscopy. Over the past 5 years, SMB has focused on the development of standards, automation, hardware developments, and maturing workflows to transform X-ray techniques from specialized capabilities requiring a high level of user training into engineering tools accessible to non-academic groups. This talk will describe some of the milestones and capabilities (i.e. hardware, controls, and analysis) that have been developed over this period, including a 23-element energy dispersive detector, an industrial robot (50 kg payload) for sample manipulation, laser feedback positioning strategies, and integration of a highly specialized mechanical load frame (RAMSIV) with an Eiger2 X CdTe (Dectris) detector. In addition to hardware integration, SMB has been developing data and analysis-informed data-collection workflows. These workflows are critical to the MSN-C mission of delivering rigorously validated reduced data sets to users, rather than raw X-ray data. The team has a diverse background of skills (materials, engineering, diffraction, software, and more) to work with defense and industry specialists without the expectation that users become experts in X-ray diffraction.

Speaker: Kelly Nygren (Cornell University)

SRI_Nygren.pdf

56 Status of the FORMAX (Forestry) Beamline

The ForMAX beamline at the MAX IV Laboratory provides multiscale and multimodal structural characterization of hierarchical materials from nm to mm length scales, by combining small- and wide-angle x-ray scattering (SWAXS), scanning SWAXS imaging, and full-field microtomography [1]. The construction and operation of the beamline is funded by the Knut and Alice Wallenberg Foundation and industrial partners to advance research and development of sustainable materials and specialty chemicals from the forest, but it is also open for general users within, e.g. materials science, food science, and biomedical imaging. We will present the beamline and selected scientific results from the first year of user operation.

[1] K. Nygård et al., J. Synchrotron Rad. 31, 363-377 (2024).

Speaker: Kim Nygard (MAX IV Laboratory)

ForMAX_Fig3_updated.png

57 SWIFT: the new Quick-EXAFS flagship beamline for Diamond-II

SWIFT: the new Quick-EXAFS flagship beamline for Diamond-II

SWIFT (Spectroscopy Within Fast Timescales) is a beamline dedicated to operando X-ray Absorption Spectroscopy, selected as one of the new flagship instruments that will be added to the present beamline portfolio at Diamond Light Source. The beamline is expected to take users shortly after the Diamond-II upgrade, in December 2029. Profiting from the opportunities provided by the Diamond-II lattice, the SWIFT source will be placed in one of the newly created straight sections. The source will be a multipole wiggler source. This, in combination with a LN2-cooled, Quick-EXAFS monochromator and high throughput detectors will allow the acquisition of EXAFS data on samples under operation conditions at fast pace, also in the case of dilute systems that need fluorescence detection acquisition mode. The beamline design includes two experimental end-stations, with one experimental hutch dedicated to ‘bulk samples’ and a second hutch providing a small focus for the analysis of samples that require fine spatial resolution. Both end-stations will provide infrastructure for catalysis experiments and are designed to host complex sample environments. Specific developments are planned for the development of the controls, data acquisition and analysis software stack, including integration of ancillary instrumentation to support effectively the acquisition of time-resolved experiments.

Giannantonio Cibin, Monica Amboage, Luke Keenan, Andrew Peach, Federico Masi, John Sutter, Harriott Nowell, Sofia Diaz-Moreno
Diamond Light Source, Harwell Science and Innovation Campus, OX11 0DE Didcot (UK)

Speaker: Giannantonio Cibin (Diamond Light Source Ltd.)

58 First Commissioning Results from the XFELO Setup at the European XFEL

We present the first commissioning results of the XFEL laser oscillator (XFELO) demonstrator project, a joint European XFEL and DESY effort.
XFELOs promise unprecedented coherence, stability and brilliance in the hard X-ray regime. Their successful implementation would mean a leap forward for the field of FELs, opening new experimental opportunities and facilitating more demanding experiments at FEL facilities due to the increase in reproducibility and spectral flux.
The setup currently being developed at the European XFEL aims to test the feasibility of a cavity-based oscillator at a super-conducting high-repetition rate XFEL facility.
With two diamond crystals close to perfect backscattering geometry a bandwidth of 20 meV at a fixed X-ray photon energy of 7 keV should be achievable.
Photon pulses with mJ-level pulse energies and high pulse-to-pulse stability are within the potential reach of this demonstrator setup.
The scope of the project with its inherent challenges, the current status, and first results will be presented in this contribution.

Speaker: Immo Bahns (Eur.XFEL (European XFEL))

59 A novel R&D beamline for Industrial Applications with Intense, High-Energy Undulator Radiation

Engineers and researchers in manufacturing industries are highly interested in what happens in their manufactured components and products when the products are in long-term operation because materials in the components might be subject to degradation and damage due to the long-term operation. Manufactures’ demands for synchrotron-based X-rays are currently shifting from modeled specimens for operando experiments or small pieces extracted from the components by cutting to their mass-produced components without any cutting. The upgrade of SPring-8 named SPring-8-II will meet the demands of high-energy X-rays. In-vacuum undulators at SPring-8-II will provide pink beams with substantially reduced energy tails at the spectroscopic lower and higher sides for a specific harmonic. A specific harmonic of the pink beam will be able to be extracted using an X-ray prism called harmonic separator [1]. Then, brilliant high-energy pink beam with an energy band width of 1% will be obtained without any monochromators.

We have tested the concept of SPring-8-II in terms of the high-energy pink beams using double multilayer monochromators at SPring-8 [2]. We fabricated multilayer mirrors designed for 100 keV and installed them to a undulator beamline BL05XU of SPring-8. We obtained a pink beam with a band width of 1.0% for 19th harmonic of undulator radiation with 1st harmonic of 5.26 keV. We gained a 100-keV pink beam with total flux of 3$\times$10$^{13}$ photons/s and prepared a 4-m-long atmospheric section called a high-energy test bench section for the use of the pink beam in the second optical hutch at BL05XU. In this presentation, we show some highlighted results of experiments at the high-energy test bench section based on actual and potential industrial demands. Computed tomography and laminography enable three-dimensional (3D) imaging of metals and ceramics as well as resin materials inside manufactured components. Orientation microscopy with a 3D X-ray diffraction method [3] is sensitive to plastic deformation, creep, and fatigue of polycrystalline materials. Residual stress measurements with a strain scanning method allow us to evaluate stress in metallic components. These capabilities are suitable to investigate degradation, fatigue, and damage of materials inside manufactured components and products with metal housing.

References:
[1] I. Inoue et al., J. Synchrotron Rad. 25, 346 (2018).
[2] H. Yumoto et al., Proc. of SPIE Vol. 11492, 114920I (2020).
[3] J. Kim et al., J. Appl. Cryst. 56, 1416 (2023).

Speaker: Yujiro Hayashi (RIKEN SPring-8 Center)

60 Sub-Hour 3D Fly-Scanning Ptychography at I13-1 Beamline of Diamond Light Source

X-ray ptychography is one of the most used nanoscale imaging techniques at synchrotron facilities around the world. The upgrade of many synchrotrons to diffraction limited rings increases dramatically the coherent flux available up to two orders of magnitude. To use at the best the x-ray beam enhancement, the ptychography community is focusing on increasing the acquisition speed of the technique development various methods: from multibeam to fly scanning$^{1,2,3,4,5,6,7}$.
Here we present the latest advances in fast ptychography at the I13-1 beamline of Diamond Light Source. We describe a detector-limited fly-scanning approach$^{8}$ where the maximum ptychographic acquisition rate is defined by the maximum detector rate. We combine this fly-scanning method with the SELUN prototype detector from DECTRIS, which is capable of 120kHz in continuum mode, to perform 100 kHz ptychographic acquisition.
We show recent experimental results, including sub-hour 3D ptychography. We discuss the current limitations, future developments, and potential applications.

[1] Pelz, P. M. et al. Appl. Phys. Lett. 105, 251101. https://doi.org/10.1063/1.4904943 (2014).
[2] Deng, J. et al. Rev. Sci. Instrum. 90, 083701. https://doi.org/10.1063/1.5103173 (2019).
[3] Clark, J. N., Huang, X., Harder, R. J. & Robinson, I. K. Opt. Lett. 39, 6066–6069. https://doi.org/10.1364/OL.39.006066 (2014).
[4] Huang, X. et al. Sci. Rep. 5, 9074. https://doi.org/10.1038/srep09074 (2015).
[5] Odstrčil, M., Holler, M. & Guizar-Sicairos, M. Opt. Express 26, 12585–12593. [7] https://doi.org/10.1364/OE.26.012585 (2018).
[6] Jones, M. W. M. et al. J. Synchrotron Radiat. 29, 480–487. [9] https://doi.org/10.1107/S1600577521012856 (2022).
[7] Jiang, Y. et al. Appl. Phys. Lett. 119, 124101. https://doi.org/10.1063/5.0067197 (2021).
[8] Batey, D., Rau, C. & Cipiccia, S. Sci Rep 12, 7846 (2022). https://doi.org/10.1038/s41598-022-11292-8 (2022)

Speaker: Darren Batey (Diamond Light Source)

Siemens110kHz_v2.png

61 The X-ray Pump Probe Instrument Upgrade for LCLS-II HE: Enhancements and Challenges

Speakers: Rebecca Armenta (SLAC National Accelerator Laboratory), Rebecca Armenta (SLAC National Accelerator Laboratory)

Mikrosymposium 7/2: Imaging and Cohrerence Applications

62 The high throughput x-ray micro-CT and long working distance x-ray nano-CT

Speaker: Gung-Chian Yin (NSRRC)

63 TOMCAT 2.0: Multiscale, Multimodal Dynamic Tomographic Microscopy

For almost two decades, the TOMCAT beamline has been providing cutting-edge multiscale, multimodal dynamic tomographic microscopy to a heterogeneous international scientific community. To maintain and strengthen our role in this field – fully leveraging on the upcoming diffraction limited SLS2.0 machine [1] – our team is driving a major beamline upgrade project (TOMCAT 2.0) featuring a significant refurbishment of the current instrument (S-TOMCAT), based on a new high-field superconducting bending magnet as well as a brand-new beamline (I-TOMCAT) based on an insertion device of latest generation [2].

Starting in summer 2025, TOMCAT 2.0 will offer to a wide academic and industrial community improved dynamical, high-throughput multidimensional and multimodal imaging capabilities, with a broad range of spatial resolutions (from 100 nm up to 10 μm) and energies (from 8 up to 50-80 keV). TOMCAT 2.0 on SLS 2.0 will profit from a smaller source size and a higher photon flux at most energies, leading to an overall enhancement of image quality. The generalized increase in photon flux - depending on the energies up to a factor 1000 compared to the old instrument - will enable to simultaneously profit from both higher spatial and temporal resolutions, pushing different flavours (in-situ, operando, in-vivo and in-fieri) of dynamic tomographic imaging towards unexplored frontiers. High throughput capabilities without compromises on image quality or spatial resolution, for the (semi-) automatic analysis of hundreds of specimens will also become available. Photon hungry chemistry revealing techniques like fluorescence imaging are currently mostly limited to the 2D (radiographies or in the best case selected tomographic slices) case. The increased photon flux coupled to improved X-ray hyperspectral interpolating detectors will pave the way to rapid 3D chemical imaging, which might routinely complement the sample microstructure with spectroscopic information.

In this contribution, we will present the TOMCAT2.0 project and explain how we are deploying the multiscale, multimodal dynamic tomographic microscopy program across S- and I-TOMCAT. We will report first results towards the realization of an innovative, high-temperature superconducting undulator [2] as well as some new optical concepts to efficiently exploit the entire beam for full field X-ray microscopy [3], to perform X-ray scattering tensor tomography [4] as well as full-field X-ray fluorescence tomography [5]. We will also briefly introduce our efforts towards event-guided temporally super-resolved X-ray imaging [6].

References:

[1] https://www.psi.ch/de/sls2-0,(2024).
[2] Zhang, K., Pirotta, A., Liang, X. Y., Hellmann, S., Bartkowiak, M., Schmidt, T., Dennis, A., Ainslie, M., Durrell, J. & Calvi, M. Record Field in a 10 Mm-Period Bulk High-Temperature Superconducting Undulator. Supercond Sci Tech 36, (2023), doi: 10.1088/1361-6668/acc1a8
[3] Samadi, N., Vila-Comamala, J., Shi, X. B., Sanli, U. T., David, C., Stampanoni, M. & Bonnin, A. Refractive Axicon for X- Ray Microscopy Applications: Design, Optimization, and Experiment. Optics express 31, 2977-2988, (2023), doi: 10.1364/Oe.478114
[4] Kim, J., Kagias, M., Marone, F. & Stampanoni, M. X-Ray Scattering Tensor Tomography with Circular Gratings. Applied Physics Letters 116, (2020), doi: 10.1063/1.5145361
[5] Marone, F., Ferreira Sanchez, D., Bergamaschi, A. & Stampanoni, M., Towards Time Resolved Multi-Scale X-Ray Fluorescence Tomographic Microscopy at I-Tomcat, in Submitted to SRI 2024.(2024)
[6] Wang, H., Hadjiivanov, A., Blazquez, E., Schlepütz, C. M., Stampanoni, M. & Lovric, G., Event-Guided Temporally Super-Resolved Synchrotron X-Ray Imaging, in Submitted to SRI2024.(2024)

Speaker: Marco Stampanoni (ETH Zürich - Paul Scherrer Institut)

64 ID03, the New Hard X-ray Microscopy Beamline at the ESRF

The newly built beamline ID03 specializes in hard x-ray microscopy. The main technique offered is dark field x-ray microscopy (DFXM), as pioneered on the prototype instrument on ID06-HXM.

DFXM is a combination of x-ray topography and full field microscopy, where an x-ray objective lens is placed in the Bragg diffracted beam between the sample and a high resolution detector. The magnified image has an effective resolution of approximately 150 nm and is sensitive to minute variations of the crystal lattice, such as strain fields, dislocations, domains formed by phase transitions, etc. The technique can be applied to a wide range of materials, ranging from structural materials such as metals and alloys to functional materials such as ferroelectrics to biominerals.

ID03 was designed from the ground up to offer the best experimental conditions for DFXM with photon energies ranging from 12 to 60 keV. The source device is a latest-generation cryogenically cooled permanent magnet undulator (CPMU) with period 16 mm and a minimum gap of 5 mm (a future upgrade to 4 mm is planned). Most of the head load from this device is absorbed in the Front End. The first optical element is a multilayer monochromator, which receives up to 3.6 kW in a 2(h) x 1(v) mm$^2$ white beam. This is followed by a diagnostics module and Si(111) channel cut monochromator that can be used optionally (i.e. experiments can be carried out with pink (bandwidth $\approx 10^{-2}$) or monochromatic (bandwidth $\approx 10^{-4}$) beam. The beam can be pre-focused by a transfocator equipped with diamond refractive lenses.
The experimental station was transferred from ID06-HXM. However, it is now housed in a hutch that is temperature controlled to $\pm 0.1^\circ$ C. The goniometer was upgraded to a geometry optimized for `topo-tomo' scans that can be reconstructed into a volume map of the strain fields within the sample.

The beamline started user operation in April 2024 and is open for user proposals via the ESRF general user programme.

Speaker: Carsten Detlefs (European Synchrotron Radiation Facility)

65 Observing the Ultrafast Structural Response of Liquid Water Subject to Strong XFEL Radiation

Given its relevance to biological systems and chemical synthesis, the radiolysis of water has been studied extensively in the past. Unlike previous studies, however, in this work, we study the ultrafast response of liquid water at elevated pressures between 50 and 225 bar. Surprisingly, when subject to intense X-ray radiation at 10 keV, the water molecules are observed to form a new long-range structured response between Q = 0.1 - 0.2 inverse Angstrom. The response is short-lived, spanning only 2.2 ps, and has not been previously unaccounted for. At small length scales, a heating effect is seen to dominate the signal. This talk will discuss the interpretation of these experimental results, which were conducted at the SPring-8 user facility using the SACLA X-ray Free Electron Laser (XFEL).

Speaker: Khaled Younes (Stanford University)

66 In Situ and Tomography Developments at Diamond’s Hard X-ray Nanoprobe

Hard X-ray nanoprobes offer access to a crucial experimental parameter space, with spatial resolutions and fields of view bridging between electron microscopies and larger scale studies. Through the use of different imaging modalities they provide an exciting opportunity to correlate chemical and structural information at the nanoscale. The combination of the penetrating power of hard X-rays with the high spatial resolution makes an ideal probe for studying systems in situ or in operando.
Beamline I14 is the hard X-ray nanoprobe beamline at Diamond Light Source, UK [1]. With a focussed X-ray probe of 50nm, and a scannable energy range of 5-20keV the beamline is optimised for nanoscale X-ray microscopy studies using a combination of X-ray fluorescence (XRF), X-ray absorption near-edge spectroscopy (XANES) and X-ray diffraction (XRD) mapping and imaging (DPC, ptychography) [2]. The novel delta robot based scanning system provides high stability and high precision scanning over a large range whilst the endstation is designed with the experimental flexibility to allow easy interchange of sample environments and mounts, [1, 3] creating new opportunities for in situ and in operando research. In addition to an overview of the technical capabilities, we will also showcase how these techniques have successfully been applied in electrochemical research across different systems and techniques. We use a 50 nm beam and a flexible open endstation to probe a wide variety of samples and sample environments at the nanoscale. Recent advancements at the beamline have included expanding the options for in situ experiments and adding tomography capabilities for 3D imaging at the nanoscale [4]. Adapting commercial in situ TEM holders, we have developed beamline compatible and correlative in situ MEMS based environments for both liquid and gas, with heating and biasing options available [5].

In addition custom made sample environments for battery, liquid cell and solar devices have been incorporated into the multipurpose endstation. These capabilities are regularly used by our user communities, with examples from perovskite, battery and biological research themes.
These science cases will be presented alongside an overview of the adapted in situ holders, highlighting how nanoprobe modalities can play an important role in multi length scales studies. The tomography capabilities have also been developed for X-ray fluorescence, differential phase contrast imaging and ptychography experiments. A workflow has been developed using hardware and software tools for sample mounting, alignment, data collection and processing to enable a user friendly experience. The processes and scientific highlights will be presented.

References: 1. P. D. Quinn, L. Alianelli, M. Gomez-Gonzalez, D. Mahoney, F. Cacho-Nerin, A. Peach and J. E. Parker, The Hard X-ray Nanoprobe beamline at Diamond Light Source, J. Synchrotron Rad., 2021, 28, 1006-1013.
2. P. D. Quinn, F. Cacho-Nerin, M. Gomez-Gonzalez, J. E. Parker, T. Poon and J. M. Walker, Differential phase contrast for quantitative imaging and spectro-microscopy at a nanoprobe beamline, J. Synchrotron Rad., 2023, 30, 200-207.
3. J. Kelly, A. Male, N. Rubies, D. Mahoney, J. M. Walker, M. A. Gomez-Gonzalez, G. Wilkin, J. E. Parker and P. D. Quinn, The Delta Robot-A long travel nano-positioning stage for scanning x-ray microscopy Rev. Sci. Instrum., 2022, 93, 043712.
4. J. M. Walker, H. J. M. Greene, Y. Moazzam, P. D. Quinn, J. E. Parker and G. Langer, An uneven distribution of strontium in the coccolithophore Scyphosphaera apsteinii revealed by nanoscale X-ray fluorescence tomography, Environ. Sci.: Process. Impacts, 2024.
5. G. T. v. d. Kerkhof, J. M. Walker, S. Agrawal, S. M. Clarke, M. H. Sk, D. J. Craske, R. Lindsay, M. Dowhyj, A. Osundare, M. E. Schuster and J. E. Parker, An in situ environment for synchrotron hard X-ray nanoprobe microscopy, Mater. High. Temp., 2023, 40, 371-375

Speaker: Jessica Walker (Diamond Light Source)

Abstract SRI 24_insitu_final.pdf

67 High-Throughput and Efficient Hard X-ray Projection Imaging with a sub-5 nm Resolution

The state of the art in X-ray microscopy is based on ptychography, which obtains high resolution approaching 5 nm by recording diffraction from the sample using a focused beam at photon energies of about 5 to 20 keV [1]. Robust algorithms are used to recover the diffraction phases and obtain an image of the complex-valued transmission of the sample. Achieving the high resolution requires measuring diffraction signals at high scattering angles. These diffraction intensities are weak and easily corrupted by background noise and parasitic scattering, requiring a larger dose to the sample than necessary. Significant efforts are needed to avoid this noise, making the method less practical and user-friendly. We have recently improved the fabrication of multilayer Laue lenses (MLLs) to focus hard X-rays with a high convergence angle (or numerical aperture, NA) [2,3]. In a ptychography measurement, this high convergence angle overcomes the problems of sensitivity to noise by providing a strong zero-order reference beam that coherently interferes with the weak scattering from the sample. A large field of view can be covered in a few scan steps (and detector frames) by placing the sample considerably out of the focus. This is the geometry of near-field ptychography where the detector captures a series of projection holograms. We show that near-field ptychography with MLLs is capable of achieving high resolution imaging with a high efficiency. We carried out the experiment at P11 beamline of PETRA III at DESY, Hamburg. An imaging resolution of about 4 nm was achieved at a photon energy of 17.4 keV with lenses of 0.014 NA from a hierarchical nanoporous gold structure, by ptychographically reconstructing projection holograms recorded at a magnification of more than 32,000 directly on a pixel-array detector [4]. A follow-up systematical numerical study illustrates the advantage of projection imaging modality over conventional diffraction-based method in terms of background noise tolerance.
References
1.Pfeiffer, F. X-ray ptychography. Nat. Photonics 12, 9–17 (2018).
2.Dresselhaus, J. L. et al. Precise wavefront characterization of x-ray optical elements using a laboratory source. Rev. Sci. Instrum. 93, 73704 (2022).
3. Bajt, S. et al. X-ray focusing with efficient high-NA multilayer Laue lenses. Light Sci. Appl. 7, 17162 (2018).
4. Zhang, W. et al. Hard X-ray projection imaging below 5 nm resolution. Submitted (2024).

Speaker: Wenhui Zhang (FS-CFEL-1 (Forschung mit Photonen Experimente 1))

68 Towards an Unified System Integrating X-ray Spectral and Phase Contrast Imaging

The combination of X-ray spectral and phase contrast imaging offers complementary advantages for comprehensive imaging and analysis of complex samples. Such combined approach (XSPI) enables simultaneous visualization of structural features and elemental composition, facilitating quantitative multi-modal characterization of materials with diverse compositions and properties [1]. This integration yields both high visibility of soft tissues and effective separation of high-Z materials augmenting the performance of X-ray imaging systems, particularly in applications such as medical imaging, material science and cultural heritage. In the frame of the INFN project Sphere-X (Spectral Phase Retrieval X-ray imaging), we are developing a unique synchrotron radiation based XSPI system (Figure 1), which is under test at the SYRMEP bending magnet beamline at Elettra. This novel X-ray imaging system yields spectral information and retrieves the phase simultaneously in a single acquisition procedure. Spectral information is obtained by a cylindrically bent Si Laue crystal which disperses the polychromatic synchrotron radiation in the vertical diffraction direction onto a 2D detector, which is located downstream the horizontal focal line where the sample is placed. The diffraction orientation, asymmetry angle and bending radius of the crystal is chosen such that the geometrical and polychromatic foci are congruent [2]. Multidimensional CT images are obtained by rotation and translation of the sample through the vertically narrow focused line beam. The energy resolution and energy range can be tuned by adjusting the bending radius and the crystal-to-detector distance. This allows to fit either simultaneously several absorption edges or a single absorption edge with high energy resolution into the vertical field of view of the detector. As a result the X-ray spectral imaging part allows either multi material decomposition on the mg/ml level or single shot spatially resolved EXAFS/XANES imaging. The beam tracking edge-illumination technique [3] is applied to obtain the phase contrast information. Utilizing beamlets generated by an absorption mask upstream the bent crystal in combination with a dithering process yields high resolution parametric images describing absorption, differential phase/refraction and scattering. Inserting the phase image into the material decomposition algorithm allows retrieving an additional material while keeping high contrast and spatial resolution of X-ray phase contrast in low density objects. In this presentation we provide an overview of our XSPI system, highlighting its principles, advantages, and applications. We discuss recent advancements in instrumentation, simulation, data processing algorithms, and preliminary imaging results.

Acknowledgements. This work was supported by the Italian National Institute for Nuclear Physics (INFN), National Scientific Commission 5

Figure 1: Schematic layout of the XSPI system (adapted from [2]).

[1] Brombal L. et al., Phys. Med. Biol. 69, 075027 (2024)
[2] Zhu Y. et al., Phys. Med. Biol. 59, 2485–2503 (2014)
[3] Vittoria F.A. et al. Appl. Phys. Lett. 106, 224102 (2015)

Speaker: Fulvia Arfelli (University of Trieste and INFN)

figure1_arfelli.jpg

Mikrosymposium 9/1: New Trends in Crystallography and Structural Biology: MS9/1

69 Resolving Hydrodynamic Interactions in Crowded Proteins Solutions with Coherent X-Ray Scattering at XFELs

Exploring how proteins move within cells is essential for understanding various biological processes, such as reaction rates and transport of molecules within the cytoplasm. Here I will present results from our recent study, which addresses the influence of hydrodynamic interactions on the diffusion of proteins on the molecular scale. By employing advanced protein megahertz X-ray Photon Correlation Spectroscopy (MHz-XPCS) at the European X-ray Free-Electron Laser (XFEL) [1], we observed protein movement in concentrated ferritin solutions at molecular scales and microsecond timescales [2].

Our findings reveal the phenomenon of De Gennes narrowing, which points to cooperative behavior among proteins, highlighted by a peak in the hydrodynamic function, H(q). Theoretical models based on colloid theory match our experimental data when both short- and long-time diffusion coefficients are considered. The intensity autocorrelation function, g2(q,t), shows a non-exponential decay pattern due to these diffusion coefficients, suggesting the presence of cage effects.

These results provide significant insights into how proteins interact and move in crowded environments. Such knowledge can contribute to enhancing the design and effectiveness of drug delivery systems by better understanding the dynamics of molecular diffusion in dense solutions.

[1] Reiser et al. Nat. Commun. 13, 5528 (2022)
[2] Girelli et al. under review (2024)

Speaker: Foivos Perakis (Department of Physics, Stockholm University)

70 MicroMAX – Time-resolved crystallography at MAX IV

The new 4th generation storage ring sources, such as the MAX IV Laboratory 3 GeV ring, gives new possibilities to study dynamics using crystallography. The MicroMAX beamline that recently started its user operation is designed to be flexible both in terms of X-ray beam and experiment setup. The focus is on serial and time-resolved crystallography but with state-of-the-art functionality also for high-throughput single crystal data collections.

MicroMAX is equipped with a diffractometer for rotational crystallography as well as serial crystallography using fixed target supports and flow injectors (high viscosity extrusion, capillary, microfluidics). The diffractometer is supported by an in-house designed sample table with a breadboard controlled and constrained by six legs with micrometer precision. A beam conditioning unit upstream of the sample table includes an X-ray chopper providing different combinations of pulse length (down to 10 microseconds), repetition rate (up to 2.2 kHz) and duty cycle (0.8 – 70%). The inhouse designed detector table supports two detectors, an Eiger2 X 9M CdTe photon counting hybrid pixel detector and a Jungfrau 9M Si integrating hybrid pixel detector (on-loan from PSI). The end station is also equipped with an automatic sample changer (ISARA2) that can be used in cryogenic conditions housing up to 29 unipucks but can also exchange crystallisation plates and room-temperature spine-based sample holders. Experiments are controlled by MXCuBE with ISPyB managing sample information, metadata and analysis results.

The beamline has a second experiment hutch that can be used for other activities while the first hutch is in X-ray operation. Initially the second hutch is used as laser and off-line UV/vis spectroscopy laboratory. It has a nano-second pump laser system covering the wavelength range of 210 – 2600 nm that can be used either for the spectroscopy setup or brought to the first hutch X-ray setup using an optical fibre.

The beamline has two monochromators, a crystal monochromator giving a narrow bandwidth beam with up to 10^13 photons/s and a multilayer monochromator giving a wider bandwidth (up to 1%) with more than 10^14 photons/s. The X-ray beam is initially focused by beryllium X-ray lenses down to around 10 micrometers but a mirror system will be added giving a beam size down to one micrometer. This system is quite flexible in terms of changing beam size at the sample.

MicroMAX has been funded by the Novo Nordisk Foundation grant number NNF17CC0030666.

Speaker: Thomas Ursby (MAX IV Laboratory, Lund University)

71 Next-generation Automation and Remote-access Crystallography

Aina Cohen (representing the entire SSRL-SMB team)
Structural Molecular Biology (SMB), Stanford Synchrotron Radiation Lightsource (SSRL), SLAC National Accelerator Laboratory, Stanford University, Menlo Park, United States of America

Structural biologists are undertaking increasingly challenging projects including the study of membrane proteins and complex multi-component machines. Structural investigations are also transitioning beyond solving a single static structure, to the application of a series of sequential structural snapshots to provide details of the atomic positions and motions that define the relationships involved in molecular recognition, transition state stabilization, and other aspects of the biocatalytic process. The success of these experiments requires careful optimization of samples and experimental setups, often involving multiple experiments at the laboratory bench and the beamline, where automation serves as an enabling technology to efficiently deliver multiple crystals and meet stringent timing requirements.
Developments at SSRL and LCLS-MFX will be presented that tackle challenges involved in the use of very small and radiation-sensitive crystals and to perform time-resolved crystallography. To facilitate the handling and optimization of delicate crystals, new in situ crystallization and remote data collection schemes have been released that avoid direct manipulation of crystals, support robotic sample exchange, and allow full rotational access of the sample in a controlled humidity environment. By simplifying crystal handling and transport at near-physiological temperatures, these technologies remove barriers to enable more widespread use of serial crystallography methods for studies of metalloenzyme structure and protein dynamics. Strategies for time-resolved measurements and data analysis tools that provide rapid feedback for experimental optimization during fast-paced experiments will also be described.

Speaker: Aina Cohen

72 Time-Resolved Crystallography Captures Light-Driven DNA Repair

Photolyase is an enzyme that uses light to catalyze DNA repair. To capture the reaction intermediates involved in the enzyme’s catalytic cycle, we conducted a time-resolved crystallography experiment. We found that photolyase traps the excited state of the active cofactor, flavin adenine dinucleotide (FAD), in a highly bent geometry. This excited state performs electron transfer to damaged DNA, inducing repair. We show that the repair reaction, which involves the lysis of two covalent bonds, occurs through a single-bond intermediate. The transformation of the substrate into product crowds the active site and disrupts hydrogen bonds with the enzyme, resulting in stepwise product release, with the 3′ thymine ejected first, followed by the 5′ base.

Speaker: Thomas Lane (FS-PS (Photon Science))

73 A Compact, Reliable Drop-on-Demand Sample Delivery System for Time-Rresolved Serial Femtosecond Crystallography at SACLA

Serial femtosecond crystallography (SFX) is a method for obtaining damage-free diffraction patterns of protein microcrystals even under near-physiological temperature conditions by utilizing intense, ultrafast X-ray free-electron laser (XFEL) pulses$^{1,2}$. Moreover, SFX is applicable to analyze chemical reactions initiated by various triggers, such as substrates, ligands, heat, and light, on timescales of tens of femtoseconds to seconds through probing time-resolved structural changes of protein molecules$^{3,4}$.

In SFX, however, a large amount of sample consumption has been problematic, as seen in the gas-dynamic virtual nozzle that requires a flow rate of the order of 10 µl/min$^{5,6}$. Fuller et al. developed a drop-on-tape (DOT) sample delivery system, ejecting a few nanoliter-scale droplets from an acoustic injector onto a moving belt for XFEL irradiation$^{7,8,9}$.

Recently, we have developed a compact drop-on-demand sample delivery system employing high-frequency piezo-type nanoliter droplet injectors. In this system, the sample droplets attached to a thin polyimide film tape are vertically transported and delivered to the XFEL pulses with high reliability. In contrast to the previous system, the new system is applicable to thin droplets with various viscosities of the sample slurry. Using this device, we have successfully demonstrated mix-and-inject SFX experiments of enzymes with sample consumption as low as that for the high-viscosity injector. Details will be given in the presentation.

[1] Chapman, H. N. et al., Nature, 470, 73 (2011).
[2] Boutet, S. et al., Science, 337, 362 (2012).
[3] Nango, E. et al., Science, 354, 1552 (2016).
[4] Orville, A. M., Curr. Opin. Struct. Biol. 65, 193 (2020).
[5] DePonte, D. P. et al., J. Phys. D: Appl. Phys. 41, 195505 (2008).
[6] Weierstall, U., Philos. Trans. R. Soc. B Biol. Sci., 369, 20130337 (2014).
[7] Roessler, C. G. et al., Structure, 24, 631-640 (2016).
[8] Fuller, F. D. et al., Nat. Methods, 14, 443 (2017).
[9] Butryn, A. et al., Nat. Commun., 21, 4461 (2021).

Speaker: Dr Jungmin Kang (RIKEN SPring-8 Center)

74 Capturing Ultrafast Molecular Motions and Lattice Dynamic Response in a Spin Crossover Thin Film Using Femtosecond Electron Diffraction and X-ray Diffraction

Structure determines function, and one of the great dream experiments in science is to directly observe atomic motions during the defining moment when matter transforms from one state to another and witness the key reaction modes directing chemistry. X-ray diffraction (XRD) on solid-state samples provides direct information on how atoms specifically respond and rearrange to stabilize the excited state. Structural dynamics from XRD and electronic dynamics from optical and X-ray spectroscopy are complementary to fully understand photochemical mechanisms. The European XFEL provides capabilities to carry out these studies, in particular high photon flux with ultra-short X-ray pulses, high repetition rates, and extreme focusing. In the Hamburg research landscape, the ultrafast electron diffraction (UED) at REGAE and the XRD at EuXFEL have proven to be invaluable resources for investigating how atoms specifically respond and rearrange to stabilize the excited state in solid-state materials.

In this contribution, we show experimental data obtained by two complementary methods, including UED and XRD at the EuXFEL beamline FXE, as a showcase of the potential application of these two new ultrafast probes. The developments of MeV-electron and X-ray free electron laser (FEL) facilitates the application of UED and ultrafast XRD with sub-100 fs time resolution, high signal-to-noise and momentum transfer (q) resolution. Therefore, it is now possible to simultaneously monitor the molecular motions and the lattice volume changes in quasi-crystalline SCO nanoparticle of well-controlled size and morphology with such high temporal resolution.

The results on a novel SCO materials Fe(HB(tz)3)2 (HBTZ) (tz= 1,2,4-triazol-1-yl) nanocrystalline thin film [1-2] unveiled a detailed picture of the transient coupling between spin-state switching and vibrational degrees of freedom, along with the development of nanometric strain wave on thin films upon photoexcitation. Due to the epitaxial orientation of the thin film with the c-axis perpendicular to the surface and the high electron energy, only Bragg peaks of the (h k 0) family have been detected. This renders it impossible to refine the atomic motions during the HBTZ phase transition and study the lattice volume expansion along the c-axis (Fig. 1b). However, from our electron diffraction results, one noteworthy feature is a plateau behavior for time delay 2 ps to 12 ps (Fig. 1c), which is after the initial photoinduced SCO and before the latter lattice response. This is indicative of the formation of the photoexcited high-spin state in unrelaxed lattice. We further carried out the time-resolved XRD experiments at the FXE end-station of the European XFEL. Thanks to the high q-resolution in low q-range of X-rays, we have been able to study changes in Bragg peak positions from more crystal lattice planes. Therefore, we could elucidate the development of nanometric strain on the thin film in ultrafast timescale (Fig. 1d and 1e).

1. Ridier, K. et al. Phys. Chem. Chem. Phys. 20, 9139–9145 (2018).
2. Ridier, K. et al.. Adv. Mater. 31, 1901361–1901361 (2019).

Speaker: Yifeng Jiang (Eur.XFEL (European XFEL))

Figure 1.png

75 Dose Aware Data Collection on the Variable and Microfocus Macromolecular Crystallography Beamline I04 at Diamond Light Source

The macromolecular crystallography (MX) beamline I04 [1] at Diamond has evolved over time through various upgrade projects that aimed at increasing scientific capability but at the same time aiming for increased stability so that the best possible data can be obtained by the user. We have deviated significantly from the initial concept for beam delivery and are now providing beam through the combination of a double crystal monochromator (DCM) with a F-switch which houses compound refractive lenses (CRL) that can be brought individually into the beam path. Both devices were designed inhouse and this combination allows variable focus of a very stable beam from the microfocus regime (8 µm x 5 µm (h x v)) to larger beam sizes (up to 110 µm x 100 µm). Beam delivery within 3% RMS of the beamsize is achieved by making use of a dedicated feedback system using X-ray beam position monitors (XBPMs). The original X-ray source has been replaced by a 17.6 mm period CPMU in June 2022 and has resulted in a significant flux increase over the whole energy range (6-18 keV) thereby generating new scientific opportunities.
Optimal data collection in MX strongly depends on setting up the right data collection parameters which should be defined by the experimental aim or scientific question that is being asked. The total exposure of the sample to the X-rays must be carefully balanced versus radiation damage. It became soon clear that with the combination of the high variability of the flux profile from the source combined with the large variability of beam sizes, that the concept of exposure per data collection frame is no longer feasible. Therefore, we have implemented the concept of dose aware data collection where the user is given the option to dial a dose per data set (instead of an exposure time per frame) and this dose should of course be compatible with the experimental aim. We use the programme RADDOSE-3D [2,3] which takes known information from the beamline (energy, flux, beam size) and at the moment assumes a standard macromolecular crystal which means that the sample only contains lighter elements and combines this information in the dose calculation to produce optimal exposure times per frame and adjustment of transmission if required. Future improvements will take into account better information about sample composition and size. Currently, we aim for the shortest possible exposure time to take advantage of the Eiger2 XE 16M detector capabilities which allows acquisition rates up to 500 Hz. Depending on the experimental aim we usually implement a multi-sweep (and often multi-crystal) approach [4] using different crystal orientations which can be realised with the SmarGon multi-axis goniometer. The dose-based approach is also fully implemented in our unattended data collection (UDC) protocols. Apart from the UDC and remote interactive modes we also strongly encourage in person visits to train users in best practice dose aware data collection and enabling them to make the best choices using the available tools in the data collection software. We constantly aim to streamline the user experience further by addition of new functionality and tools.
[1] https://www.diamond.ac.uk/Instruments/Mx/I04.html
[2] RADDOSE-3D: time- and space-resolved modelling of dose in macromolecular crystallography, O.B. Zeldin, M. Gerstel, E. Garman, J. Appl. Cryst. (2013) 46, 1225-1230
[3] Estimate your dose: RADDOSE-3D, C.S. Bury, J.C. Brooks-Bartlett, S.P. Waldh, E.F. Garman, Protein Science (2018) 27, 217-228
[4] How best to use photons, Winter, G. et al., Acta Cryst. (2019). D75, 242-261

Speaker: Ralf Flaig (Diamond Light Source)

18:30 Poster Session

Wednesday 28 August

76 X-ray tomography for Circuit Neuroscience - Towards X-ray Connectomics

The brain is one of the most complex structures known. In order to understand how information is processed in mammalian brains, one needs to combine functional measurements with structural information across scales from cm to nm. In this talk, I will discuss our multi-modal, multiscale approaches, combining functional imaging in vivo in mice with different synchrotron X-ray tomography techniques[1,2]. I will illustrate how nano-holotomography can reveal circuit structure at scale, sufficient to describe input-output relationships in a brain area. Moreover, advanced sample preparation approaches[3,4] make it possible to not only prepare samples optimised for X-ray tomography but also to subsequently perform targeted volume electron microscopy with multiple samples. I will conclude by providing an outlook on what the key challenges are for X-ray tomography to delineate neural circuitry at microscopic level[5] and how to scale these approaches up to entire brains.

References
[1] - Bosch, C., Ackels, T., Pacureanu, A., Zhang, Y., Peddie, C.J., Berning, M., Rzepka, N., Zdora, M.C., Whiteley, I., Storm, M., ,,,, and A.T. Schaefer, Nature Communications 13, 2923. (2022).
[2] - A. Laugros, J. Livingstone, P. Cloetens, A. Pacureanu , A. T. Schaefer. Program No. 144.05. 2023 Neuroscience Meeting Planner. Washington DC: Society for Neuroscience (2023).
[3] - Bosch, C., Lindenau, J., Pacureanu, A., Peddie, C.J., Majkut, M., Douglas, A.C., Carzaniga, R., Rack, A., Collinson, L., Schaefer, A.T., and H. Steigmann. Appl Phys Lett 122, 143701. (2023)
[4] - Zhang, Y., Ackels, T., Pacureanu, A., Zdora, M.-C., Bonnin, A., Schaefer, A.T., and Bosch, C. Frontiers in Cell and Developmental Biology 10. (2022)
[5] - Bosch, C., Diaz, A., Holler, M., Guizar-Sicairos, M., Aidukas, T., Pacureanu, A., Mueller, E., Peddie, C.J., Collinson, L., Zhang, Y., … A. Diaz, A. Wanner and A.T. Schaefer. bioRxiv 2023.11.16.567403. (2023)

Speaker: Andreas T. Schaefer (Francis Crick Institute)

77 The recent status of High Energy Photon Source (HEPS)

One of the important tendencies in the development of synchrotron radiation sources is low emmitance. Low emmitance storage rings could provide higher brilliance and better coherence, which are very important for almost all kinds of experiments in synchrotron radiation facilities. The 4th generation synchrotron radiation facilities can provide 2 or 3 orders of higher brilliance and coherence comparing with 3rd generation ones.
In the meantime, the successful construction of Shanghai Synchrotron Radiation Facility and the great achievements in the research in this facility, inspire the users to build the new and high-performance light sources in China. In the view point of regional factors, the vast in territory of China requires the reasonable distribution of synchrotron radiation facilities which support the scientific and technological research, in order to farthest satisfy the demands of users from different regions.
Based on the above reasons, we are building a new synchrotron radiation facility in the region around Beijing: High Energy Photon Source (HEPS). The designed electron energy of HEPS is 6GeV and the emmitance is lower than 0.1nmrad. This machine can provide the hard X-ray with brilliance higher than 1022ph/s/mm2/mrad2/0.1%BW and photon energy higher than 300keV.
The construction of HEPS started in June 2019, including a 500MeV LINAC, a 6GeV booster, a 1360m-circunference storage ring, 14 public beamlines and 1 test optical beamline, as well as the auxiliary facilities and building. Before the start-up of HEPS, the R&D project (HEPS-TF) was supported during 2016-2019. The Platform for Advanced Photon Source (PAPS) was supported in 2017 in order to provide a field for technology research and the assembling of the instruments of HEPS.
The installation of LINAC started in March 2022, commissioning in March 2023. In June 2023, the electron energy of LINAC reached to 500MeV, and the bunch charge reached to 7nC.
The installation of booster started in August 2022, commissioning in July 2023. By 4 months of debugging, the electron energy reached to 6GeV and bunch charge to 5nC, in November 2023.
The installation of storage ring started in February 2023. Now all the magnets and girders are ready. The commissioning is planned in July 2024.
All the FOEs and hutches of beamlines are ready. The instruments of beamlines and end-stations are in installation. The commissioning of beamlines will start with storage ring.
In the meantime, the teams of beamlines and end-stations cooperate with users, to plan the day-one experiments and the construction of future beamlines. Several jointed research centers and laboratories are established to solve the problems of industries and explore the application of the unique experimental methods of 4th generation synchrotron radiation in frontier researches. We hope the users of HEPS can launch intensive research, instead of simple measurements in future. In order to support this purpose, the office & laboratory building as well as guesthouse, were completed.
The whole facility will be in operating at the end of 2025.

Speaker: Yuhui Dong (Institute of High Energy Physics, Chinese Academy of Sciences)

The recent status of High Energy Photon Source (HEPS).docx

78 Status of the Hard X-ray Self-Seeding at the EuXFEL

As a scheme to increase longitudinal coherence in SASE based FELs, hard X-ray self-seeding (HXRSS) has demonstrated its capability of delivering above 1mJ/eV peak pulse intensity at MHz repetition rate in the SASE2 beam line at the EuXFEL. The delivery of HXRSS started in 2021 at the EuXFEL. With the increasing user requests with stringent requirements, we explored different methods for bandwidth and background controls. Additionally, we are investigating advanced HXRSS operation schemes to further expand our operational capabilities. This presentation will provide an overview of HXRSS status, current capabilities, and future prospects.

Speaker: Shan Liu (DESY)

10:15 Coffee Break

Mikrosymposium 1/3: Beamline Optics and Diagnostics

79 The latest developments of multilayer Laue lenses

Imaging of nanometer details in structures is of critical importance to distinguish hypotheses or solve various societal problems. With X-rays this can be done non-destructively using a number of imaging modalities that each provide differing information about the sample. To obtain high resolution images, an intense coherent source and high quality optics is required. We are developing diffractive type of X-ray optics, multilayer Laue lenses, that are considered to be most promising to extend towards atomic resolution. In the past few years, we achieved substantial improvement of their quality and numerical aperture by introducing novel laboratory-based wavefront metrology based on speckle tracking, ptychography and machine learning. Our new lenses enable high resolution phase contrast imaging and extend X-ray microscopy to even higher energies for imaging at reduced dose.

Speakers: Sasa Bajt (FS-ML (Multilayer)), Sasa Bajt

80 Optimisation of Aspect-Ratio-Limited Zone Plates

Fresnel zone plates are widely used for nanofocusing in x-ray microscopy. The focusing performance is described in terms of the resolution, related to the width of the smallest outermost zones, and the efficiency, governed by the thickness of the zones and therefore the amount of phase shift imparted onto the x-ray beam. The ratio of zone thickness to width, or “aspect ratio,” is limited in all methods of zone plate fabrication, requiring compromises between efficiency and resolution.

We have developed a new zone plate design method [1] which optimizes focusing efficiency within a set of practical constraints. This phasor-based method is used to optimize - subject to a maximum aspect ratio constraint – the efficiency of binary, multilevel, and kinoform zone plates. A truncated zone plate profile is proposed, which focuses more efficiently than binary and kinoform zone plates, but with considerably higher manufacturability.

The approach is demonstrated through measurements of lenses manufactured by focused ion beam milling in gold. Relative efficiency was validated at a synchrotron hard x-ray beamline. Our phasor method provides rapid design optimization, producing the ultimate lens designs for a given manufacturing limit, and it is generalizable to incorporate any fabrication tolerances such as roughness, zone displacements, and zone wall inclination.

[1] C. M. Kewish, S. Gorelick, D. M. Paganin, M. D. de Jonge, Optimum design of aspect ratio limited x-ray zone plates. Optica 11(2), pp 251-262 (2024).

Speaker: Martin de Jonge (Australian Synchrotron - ANSTO)

81 Characterization of a Multilayer Laue Lens as Condenser for Projection Tomography to Enable the XtremeCT Requirements at the DanMAX Beamline of MAX IV

The tomographic station of the DanMAX beamline at MAX IV Laboratory entered user operation in Spring 2024. The scope of the beamline is predominantly diffraction and imaging for material science. With the XtremeCT project we aim to enable DanMAX to perform, in an optimized and disruptive manner, 3D measurements of all microstructural features within large sections of brains and bones, to visualize the full hierarchical organization and connectivity in multiscale samples, with the aim of understanding their structural function and possible connection to diseases. The goal is to achieve a voxel-to-image ratio of 104 - 105, resulting in significantly higher information density compared to current methods. To expand the field-of-view and for zooming into the cells using projection nano-tomography, a focusing X-ray optics with sub 100 nm spot size and high numerical aperture is required.
The focusing element must work across a large energy bandwidth and preserve the coherence, both essential to generate low dose 3D phase contrast tomography with a ratio between field-of-view and resolution of 10,000:1 or better, e.g. for visualizing all cells within tissues. We report here on the outcome of a pilot study using a Mo/C/Si/C Multilayer Laue Lens (MLL) from AXO DRESDEN and Fraunhofer IWS. MLLs offer a high diffraction efficiency for hard X-rays and a large energy bandwidth. Thus, even a MLL that is optimized for 20 keV can be well used in the entire photon energy range of the DanMAX beamline (15 keV – 35 keV) without sacrificing the diffraction efficiency more than a factor of 2. The MLL ensures that the incident beam diameter (~1.3 mm) is expanded by a factor of 10 to encompass the entire Field-of-View of the detector (12.0 mm).
We plan to present detailed characterization of the MLL at the DanMAX beamline, with specific emphasis of full-field tomography at the micron and sub-100 nm scale respectively. Assessment of beam quality after beam expansion has been performed as well as a comparison of the image quality and phase retrieval performance when using the MLL in projection geometry and as an objective lens.

Speaker: Nis C. Gellert (Department of Physics, Technical University of Denmark)

82 The Diamond Light Source Program for Crystal Inspection Using X-ray Topography

For monochromators and phase retarders designed for X-rays of energy over 4 keV, diffracting crystals are the material of choice. However, the cleanliness of the diffracted beam and the achievable energy resolution can be degraded by defects introduced into the bulk during growth, by scratches and pits left on the surface by polishing, and by poor clamping that deforms the crystal lattice. Diamond Light Source now has a procedure for inspecting such crystals before beamline installation, and within this, X-ray topography is a critical tool. New crystal optics are examined at the versatile bending-magnet test beamline B16, which is designed to apply topographic techniques using both white and monochromatic X-ray beams to crystals mounted in any orientation. Rocking curve imaging has been performed with a range of fields of view and spatial resolutions down to 2 µm using a set of digital detectors. Maps of defects over large surfaces have been collected using both on-the-fly scans and stitching techniques, and methods to automate stitching are being developed. Monochromator crystals, including some that were fabricated using new methods or mounted in innovative ways, have been successfully tested for strain under realistic cryocooling, and the results are helping to further improve the crystal mount and cooling. Results provided by X-ray topography are being combined with visible-light measurements made at Diamond’s Optical Metrology Laboratory into a full package of techniques for determining whether a new crystal optic should be accepted. Not only Diamond’s own beamlines, but also industrial users and other X-ray synchrotron facilities, have profited from this combination of capabilities.

Speaker: John Sutter (Diamond Light Source Ltd)

83 The Progress in Design of MLL for HEPS

Multilayer Laue lenses (MLLs) is an extension of Fresnel zone plates in the form of a volume diffracting element, which is a promising optical element in synchrotron radiation facility. By the means of dynamical diffraction theory, DC magnetron sputtering, laser etching and focused ion beam lithography, two-dimensional MLLs with 63×43 μm2 aperture and focal spot of 8×8 nm2 @ 10keV are designed and fabricated in High Energy Photon Source (HEPS). Beside the conventional MLL, Single-order focus multilayer Laue lens [1], novel figuring method for multilayer Laue lens [2] and a linear gradient multilayer Laue lens [3] were proposed by the hard X-ray nano-probe beamline of HEPS. The Single-order focusing MLL could suppresses higher-order diffractions effectively, which will substantially increase the working distance for the MLL systems. This figuring method will reduce the requirements for MLLs: the total thickness and layer placement accuracy of the multilayer structure, which are the main constraints on the development of the large aperture MLLs, thus making the fabrication of larger NA MLL with a longer working distance possible. The linear gradient MLL could achieve considerable efficiency as a wedge MLL but with simpler fabrication method. These new designs for MLL can reduce the difficulty of preparing MLL to a certain extent as well as increase the focusing performance and practicality of MLL.

[1] Ji B, Yue S, Zhou L, et al. Single-order focus multilayer Laue lens[J]. Applied Optics, 2022, 61(27): 8028-8033.
[2] Ji B, Yue S, Zhou L, et al. Novel figuring method for a multilayer Laue lens[J]. Optics Express, 2022, 30(26): 46838-46848.
[3] Ji B, Yue S, Hou Q, et al. A linear gradient multilayer Laue lens[J]. Optics Communications, 2024, 552: 130031.

Speaker: Bin Ji (Institute of High Energy Physics, CAS)

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84 First Mirror Stability at the MAX IV Soft X-ray Beamlines

The multi-bend achromat, fourth-generation storage rings have increased beam brightness due to the order of magnitude lower emittance that can be achieved. The higher brightness comes with smaller beam sizes and narrower radiation cones which in turn deposit higher power density in the optical components. Maximizing the transmission and ensuring the stability of the brilliance from the source down to the sample via the many optical components depends on good mechanics and dealing effectively with the increased heat load and secondary particle generation.
This paper presents observations and lessons learned from the soft X-ray beamlines at MAX IV in addressing long thermal stabilization times at the first mirrors in the beamline, and the negative impacts of increased photoelectron generation at the mirror surfaces.

Acknowledgements
Research conducted at MAX IV, a Swedish national user facility, is supported by the Swedish Research council under contract 2018-07152, the Swedish Governmental Agency for Innovation Systems under contract 2018-04969, and Formas under contract 2019-02496.We acknowledge the teams at VERITAS, HIPPIE, SoftiMAX, BLOCH, FLEXPES for valuable discussions and experimental time.

Speaker: Louisa Pickworth (MAX IV, Lund University)

85 Silicon Pore Optics for ESA’s NewAthena X-ray Observatory: Dedicated Beamlines and Wide Range Reflectance Measurements

NewAthena will be the largest X-ray observatory ever flown. To achieve an effective area of 1 m² at 1 keV, a total polished mirror surface of 300 m² is required due to the grazing incidence. Based on silicon pore optics (SPO), a large X-ray lens with a diameter of 2.5 m will be installed at 12 m distance from the two detectors in the focal plane. It is composed of about 500 mirror modules (MM). Each MM consist of four stacks of about 40 silicon wafers with ribs at the backside. To optimize the reflectance in the photon energy range from 0.2 up to 10 keV, the mirror surfaces will be coated with e. g. iridium and carbon layers.
Two dedicated beamlines for SPO characterization in the PTB laboratory at BESSY II provide monochromatic radiation at 1 keV and a low divergence well below 2 arcsec: the X-ray Pencil Beam Facility (XPBF 1) [1], and the X-ray Parallel Beam Facility (XPBF 2.0) where beam sizes up to 8 mm x 8 mm are available while maintaining the low beam divergence [2]. This beamline is also used to control the focusing properties of MM during their assembly at the beamline. A movable CCD-based camera system with a vertical travel range of 2 m at 12 m distance from the MM registers the direct and the reflected beam. The positioning of the detector is verified by a laser tracker. Two similar beamlines are planned to be installed in the laboratory for the mass production of MM within the next years.
Two different beamlines in the PTB laboratory, an undulator beamline with plane grating monochromator and a dipole beamline with a four-crystal monochromator, were used to measure the reflectance in several pores of differently coated MMs in double reflection over the entire photon energy range, revealing the effects due to the absorption edges and the layer thickness of the involved materials.
References:
1. M. Krumrey, L. Cibik, P. Müller, M. Bavdaz, E. Wille, M. Ackermann & M. Collon, Proc. SPIE 7732, 77324O (2010)
2. M. Krumrey, P. Müller, L. Cibik, M. Collon, N. Barrière, G. Vacanti, M. Bavdaz & E. Wille, Proc. SPIE 9905, 99055N (2016)

Fig. 1: X-ray lens,composed of MMs
Fig. 2: MM, consisting of ribbed silicon wafers
Fig. 3: Reflectance of an Ir coated MM at higher photon energies

Speaker: Michael Krumrey (Physikalisch-Technische Bundesanstalt)

Krumrey_SRI24_Fig1.png

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Krumrey_SRI24_Fig3.png

Mikrosymposium 10/1: New Lattices and IDs: MS10/1

86 A non-standard, but competitive, lattice solution for a 4th generation light source with capabilities for Metrology applications & timing.

The PTB, Germany´s national metrology institute, has relied on synchrotron radiation for metrology purposes for over 40 years and the most prominent customers are lithography systems from ASML/ZEIS. HZB is now working on a concept for a BESSY II successor, based on a 4th generation light source with an emittance of 100 pmrad @ 2.5 GeV. It is essential, that this new facility continues to serve the PTB for metrology purposes. This sets clear boundary conditions for the lattice design, in particular, the need for homogeneous bends as metrological radiation sources. Different Higher-Order-Multi-Bend-Achromat lattices have been developed, based on combined function gradient bends and homogeneous bends in a systematic lattice design approach. All lattices are linearly equivalent with the same emittance and maximum field strength. However, they differ significantly in their non-linear behavior. Based on this analysis, the choice of the BESSY III lattice type is motivated. A special focus is set also on TRIBs (Transverse Resonance Island Buckets) to operate with two orbits as a bunch separation scheme in MBAs, for different repetition rates or for the separation of short and long bunches.

Speaker: Paul Goslawski (Helmholtz-Zentrum Berlin, HZB)

20240826_SRI_B3Lattice_PG.pdf

87 Pushing the limit in fourth-generation storage ring light source lattice design

While multi-bend achromat lattices combined with technological advances opened the way toward ultra-low emittance storage ring light sources, a number of practical and theoretical factors limit their design performances. We examine these factors through lattice design practices and explore the optimal design approach for a diffraction limited storage ring in the hard X-ray regime.

Speaker: Xiaobiao Huang (SLAC National Accelerator Laboratory)

88 New opportunities of coherent imaging and timing mode at the Elettra 2.0 storage ring light source

Picosecond-long x-ray pulses of moderate intensity and high repetition rate are highly sought after by the light source community, especially for time-resolved fine spectroscopic analysis of matter in the linear response regime. We investigate the upgrade of the Elettra 2.0 diffraction-limited storage ring light source to radiofrequency transverse deflecting cavities generating a steady-state vertical deflection of selected electron bunches. The study demonstrates the feasibility of picosecond-long x-ray pulses at MHz repetition rate, provided simultaneously to several beamlines, and compatible with the standard multi-bunch operation. The short pulse exhibits a total flux at 1–10% level of the standard single bunch emission at the sample. Transverse coherence is preserved in both transverse planes up to few hundreds’ of eV photon energy. Ultimate performance, limits and operational aspects of the scheme are analysed in an integrated accelerator-plus-beamlines perspective.

Speaker: Simone Di Mitri (Elettra Sincrotrone Trieste and University of Trieste)

89 Panoply of Insertion Devices for SOLEIL II Project

SOLEIL II is a project aiming at upgrading the present SOLEIL synchrotron to a fourth-generation light source. The photon spectral performances such as brightness and flux density will be highly increased by a drastic decrease of the natural horizontal emittance, below 100 pm.rad. The goal will be accomplished by an increase of the number of magnets and the compactness of the equipment. Big efforts on the lattice have been performed to preserve the space for present in-vacuum and cryogenic insertion devices. Nonetheless most of the space dedicated to the other types of insertion devices will be reduced by 30 %, making difficult to cover the present wide spectral range required for the beamlines using presently juxtaposed undulators. In this purpose new innovated solutions have been developed, prototyped, and tested at SOLEIL. The report will give an overview of the insertion devices portfolio which will be installed from the SOLEIL II start.

Speaker: OLIVIER MARCOUILLE (SOLEIL Synchrotron)

90 Front End Absorbers Review and Upgrade with Copper-Zirconium CuCr1Zr Apertures for ESRF-EBS

Abstract. A significant amount of cryogenic permanent magnet undulators (CPMUs) were deployed in the past at the ESRF with significantly more overall emitted spectral power and reduced gaps [1, 2]. Further insertion device (ID) upgrade plans exist with double (2x2m) CPMU arrangements and possible high-temperature superconducting IDs.
The drastically increased emission of photons and linked thermal power leads to higher thermal stresses on heat load absorbing elements in the front end. This poses challenges related to low-cycle fatigue (LCF) which is characterized by thermo-mechanical stress cycling that exceed the material yield point and occurring plastic strain [3]. Linked to the drastically reduced emittance of the new forth generation ESRF-EBS machine, new front end beam sizing components were introduced with reduced exit aperture to cut unwanted spectral energies. These were not properly validated in terms of lifetime in the run for the EBS upgrade. A review was conducted to estimate the lifespan of these new components alongside the existing 30-year-old standard front end absorbers, considering powerful current and future ID upgrades.
Alternative designs based on the copper alloy CuCr1Zr are proposed for the components that failed this review. CuCr1Zr links high thermal conductivity of copper with increased strength and hardness. Many recent ESRF-EBS heat load absorbers are almost exclusively based this material and its advantageous properties [4]. ESRF specifications for CuCr1Zr were carefully developed in the past to guarantee a minimum hardness. This enables the possibility to easily machine UHV compatible components in bulk material that include Conflat flanges with purely classic machining procedures (milling, turning, EDM-wire cutting). Complicated brazing of flanges with materials such as GlidCop-Al15 or Cu-OFHC is therefore not necessary. Few data exists about the LCF behavior of CuCr1Zr. We launched LCF tests for material produced according to the ESRF specs to obtain strain-lifetime data for reliable component lifetime prediction.

REFERENCES
[1] J. Chavanne, G. Le Bec, and C. Penel, Synchrotron Radiation News 24, 10–13 (2011).
[2] P. Falaise, P. Raimondi, C. Benabderrahmane, R. Versteegen, G. LeBec, S. Lagarde, S. White, B. Ogier, J. Chavanne, and S. Liuzzo, Proceedings of the 14th Int. Particle Accelerator Conf. IPAC2023, 3177–3180 (2023).
[3] S. Takahashi, M. Sano, T. Mochizuki, A. Watanabe, and H. Kitamura, Journal of Synchrotron Radiation 15, 144–150 (2008).
[4] F. Thomas, J.-C. Biasci, D. Coulon, Y. Dabin, T. Ducoing, F. Ewald, E. Gagliardini, and P. Marion, Proceedings of Mechanical Engineering Design of Synchrotron Radiation Equipment and Instrumentation MEDSI2016, 257–261 (2016).

Speaker: Philipp Brumund (European Synchrotron Radiation Facility, 38043 Grenoble, France)

91 Undulator Light Source with a Compact, Slender and Lightweight Frame Based on a Magnet Technology Developed for the Very-Short-Period Undulators

We have been exploring a novel method to fabricate undulator magnets having a very short period length of a few mm. Plate monolithic magnets (PMM) made of Nd-Fe-B, 100mm long with 4-mm period length have been successfully fabricated[1-4]. The 4-mm period length allows us to obtain 12-keV radiation with the first harmonic of this undulator in the 2.5-GeV light source accelerator. A connection method of these magnet plates has also been successfully developed to fabricate longer undulator magnets[5-6].
As a next step of the development, we are developing a magnetic cancellation method of an attractive force produced by the undulator main magnets by using repulsion magnets. The attractive force is effectively cancelled out by them placed outward in the magnet gap. We found that the repulsion magnets made of PMM were easily optimized in the present system where the main magnets were also made of PMM in contrast to the previous work[7].
We are also developing a compact undulator frame, in which magnetic attractive force between the main undulator magnets is effectively cancelled out by the above cancellation method using repulsion magnets. This undulator is designed as a light source for an XUV-FEL development which has been undertaken in the experimental plat-form at SP-8 for the JST-MIRAI project[8]. Target parameters of the undulator for this experiment are: period length, u=25mm, field strength K=1.4 at the gap=5mm or larger, and number of period=80. The magnet array is divided into two segments 1m long each, gap of which can be controlled independently. The weight of the undulator system is as light as 500kg/m.

References
[1] S. Yamamoto, Journal of Phys.: Conf. Ser. 425 032014, 2013.
[2] S. Yamamoto, WEOAA02, Proc. IPAC2014, 1845-1857, Dresden, Germany, 2014.
[3] S. Yamamoto, Synchrotron Radiation News 28 No.3, 19-22, 2015.
[4] S. Yamamoto, et al., J. Synchrotron Rad. 26, 1902-1910, 2019, https://doi.org/10.1107/ S1600577519013031
[5] S. Yamamoto, AIP Conf. Proc. 1741, 020029, 2016, doi: 10.1063/1.4952808.
[6] S. Yamamoto, WEXGBD1, Proc. IPAC2018, 1735-1739, Vancouver, BC, Canada, 2018, doi:10.18429/JACoW-IPAC2018-WEXGBD1.
[7] R.Kinjo, et al., S.Yamamoto, T.Tanaka, Review Scientific Instrum. 88, 073302 (2017), doi:http://dx.doi.org/ 10.1063/1.4991652.
[8] S. Yamamoto, et al., THOT10, Proc. PASJ2020, 145-149, 2020, in Japanese.

Speaker: Shigeru Yamamoto (High Energy Accelerator Research Organization, KEK)

92 Novel magnet lattice for the high-brightness upgrade of NSLS-II

Speaker: Victor Smalyuk

Mikrosymposium MS 12/1: Time Resolved Techniques: MS12/1

93 X-ray cross-correlation analysis of crystalline defects using femtosecond X-ray pulses

The liquid-to-solid phase transition is a complex process that is difficult to investigate experimentally with sufficient spatial and temporal resolution. X-ray Free Electron Lasers (XFELs) offer new opportunities for probing very small length- and short times-scales and make entirely new experiments possible. We employ femtosecond x-ray diffraction from microscopic liquid jets to study crystal nucleation in supercooled liquids of the rare gases argon and krypton. Our results provide stringent limits to the validity of classical nucleation theory in atomic liquids. Additionally, we demonstrate the advanced characterization opportunities for probing the three-dimensional reciprocal space of crystalline structures by X-ray cross correlation analysis (XCCA), which allows to distinguish different forms of stacking faults and follow their metastability during the crystallization process.

Speaker: Johannes Moeller (Eur.XFEL (European XFEL))

94 Improving the Time-Resolution for Time Resolved Solution Phase Chemistry at XFELs

The arrival of x-ray free electron lasers (XFELs) routinely made x-ray experiments with sub-500fs time-resolution possible, while additional diagnostics in combination with shot-to-shot analysis rapidly pushed this limit down to sub-100fs.
Following a decade of ultrafast time-resolved chemistry at XFELs there is a general interest to further push these temporal boundaries. ~100fs time-resolution is readily achievable by combining the nominal durations of XFEL pulses, laser pulses, timing diagnostics as well as the group velocity mismatch of a typical liquid sample jet. However, improving upon this limit has proven to be increasingly challenging and requiring developments in all aspects: compressed x-ray and laser pulses along with diagnostics and characterization, improved experimental timing diagnostics and procedures as well as thinner samples.
Here we will discuss the limitations and efforts to improve on them, including different laser compression schemes, sample delivery methods, time-tool targets and response as well as diagnostics for such experiments.
With the goal of routinely achieving ~30fs time-resolution while maximizing the signal-to-noise necessary for hard x-ray solution phase experiments often utilizing a combination of solution scattering (XSS), x-ray emission spectroscopy (XES) and x-ray absorption spectroscopy (XAS) in a multimodal setup. The improvements in temporal resolution would allow for more detailed studies of coherent dynamics, molecular vibrations, and quantum phenomena in photochemistry.

Speaker: Tim van Driel (SLAC National Accelerator Laboratory)

95 High-Throughput and High-Resolution Instrumentation for Time-Resolved Resonant Inelastic X-ray Scattering at SCS, European XFEL

The European X-ray Free-Electron Laser Facility (European XFEL) in Schenefeld, Germany enables research with free-electron laser (FEL) radiation of unique properties. The superconducting accelerator can deliver up to 27,000 electron bunches per second, used to generate ultra-short and highly coherent x-ray pulses of high average brilliance [1]. European XFEL hosts currently seven instruments for soft, tender and hard x-ray studies. The soft x-ray Spectroscopy and Coherent Scattering (SCS) instrument is optimized for x-ray spectroscopy and x-ray diffraction.

The User Consortium Heisenberg RIXS (hRIXS) spectrometer was designed and built in order to explore photoexcitation dynamic with Resonant Inelastic X-ray Scattering (RIXS) close to the transfer limit of a monochromatic FEL source [2]. RIXS is powerfull tool for microscopic studies of condensed matter, because it reveals details on charge, spin, orbital and nuclear degrees of freedom. At FEL facilities photoexcitation dynamics and novel transient states can be explored [3-6]. Initial studies were suffering from limitations due to low signal levels.

The high-repetition rate of the European XFEL, together with the unique properties of the SCS instrument, provide the ideal conditions to host a high-resolution RIXS instrument [1,2,6,7]. The mechanical design of the hRIXS spectrometer enables studies in the photon range from 400 eV up to 1500 eV and variation of the scattering angle. First results demonstrate the high stability of the instrument and feasibility of time-resolved RIXS down to 100 fs in time resolution and up to 10,000 in energy resolving power. SCS and hRIXS offer sample environment for two large user communities, one with focus on quantum materials (e.g. high-temperature superconductors) and one with focus on chemical systems/ liquid jets (e.g. photoactive catalysts). The instrument has been in regular user operation since 2022-II.

References
1. T. Tschentscher et al., Appl. Sci. 7, 592 (2017).
2. J. Schlappa at al., arXiv:2403,08461 (2023).
3. P. Wernet et al., Nature 520, 78 (2015).
4. M. P. M. Dean at al., Nature materials 15 601 (2016).
5. M. Mitrano et al., Science advances 5, eaax3346 (2019).
6. E. Paris et al., NPJ Quantum materials 6:51 (2021).
7. N. Gerasimova at al., J. Synchrotron Radiat. 29, 1299 (2022).
8. https://www.xfel.eu/facility/instruments/scs/index_eng.html

Speaker: Justine Schlappa (Eur.XFEL (European XFEL))

96 Extended Time-Resolved Experimental Capabilities and Performance at the MAX IV FemtoMAX Beamline

The FemtoMAX beamline is a unique LINAC-driven time-resolved laser pump/x-ray probe beamline dedicated to study solids and liquids. The beamline is designed to explore dynamics in condensed matter materials at time scales ranging from femtoseconds to microseconds [1]. The sub-50 fs x-ray pulses are generated in two in-vacuum undulators, with a photon energy tuneable between 1.8 – 15 keV at a repetition rate of 10 Hz. The femtosecond laser excitation source spans wavelengths of 400 nm-1.6 µm and THz frequencies. A Pilatus time-over-threshold single photon counting detector and a collection of sCMOS detectors are employed to capture SAXS/WAXS and diffraction signals. In addition, ultrashort x-ray pulses in combination with fast detectors can be used to study x-ray time resolved fluorescence from fast scintillators, nanofilms and organic materials.
Here, we present recent advances in providing methods and capabilities to the user community, this includes solution scattering and transient x-ray spectroscopy, which is under development and will be ready for general user experiments year 2024. We also present a novel approach to do timestamping and sorting pump/probe data, based on optical cross-correlation, leading to a significant increase in achievable time resolution.
With these efforts, we are widening the scientific scope of the FemtoMAX beamline and open up for building a large user community.

References
1. Enquist Henrik, Jurgilaitis Andrius, Jarnac Amelie, Bengtsson Asa U. J., Burza Matthias, Curbis Francesca, Disch Christian, Ekstrom J. Carl, Harb Maher, Isaksson Lennart, Kotur Marija, Kroon David, Lindau Filip, Mansten Erik, Nygaard Jesper, Persson Anna I. H., Van Thai Pham, Rissi Michael, Thorin Sara, Tu Chien-Ming, Wallen Erik, Wang Xiaocui, Werin Sverker, Larsson Jorgen
FemtoMAX - an X-ray beamline for structural dynamics at the short-pulse facility of MAX IV
JOURNAL OF SYNCHROTRON RADIATION 25 570-579 (2018)

Speaker: David Kroon (MAX IV Laboratory)

97 Speckle contrast from the split-and-delay unit with seeded X-ray pulses of the MID instrument at European XFEL

The split-and-delay unit (SDL) at the MID (Materials Imaging and Dynamics) instrument of the European XFEL enables the splitting of a single FEL pulse into two fractions and delay one fraction in the range of femtoseconds to 800 ps [1]. This allows the investigation of dynamic processes on a molecular level in a temporal window that is difficult to access experimentally [2]. Especially the study of small molecular liquids, such as water and aqueous solutions, will benefit from this opportunity because many temperature and concentration dependent dynamics take place on the picosecond timescale. A prime example is the intermediate scattering function of molecular water, which from molecular dynamics simulations is expected to show the formation of a two-step relaxation process that strongly depends on temperature. For room temperature, the second step is found in the time window around 1 ps [3] which is exactly centered in the accessible region of the SDL unit of MID. The feasibility of such type of experiments has been shown by a measurement on pure water with SACLA split-and-delay optics [4]. Here, we report on the speckle contrast extracted from the scattering patterns and pulse splitting characteristics with seeded beam operation, which allows a high throughput of the SDL unit and reduced beam-induced dynamics in the sample. We further discuss the first experimental results from probing water in a jet, highlighting the invaluable potential of the SDL unit in advancing our understanding of fundamental processes of ultrafast phenomena in molecular liquids like water and aqueous solutions.

[1] W. Lu et al., Rev. Sci. Instrum., 89, 6, 063121 (2018).
[2] F. Lehmkühler, et al. Appl. Sci., 11, 13, 6179 (2021).
[3] P. Gallo, et al., J. Chem. Phys., 139, 20, 204503 (2013).
[4] Y. Shinohara et al., Nat. Commun., 11, 6213 (2020).

Speaker: Claudia Goy (FS-SMP (Spectroscopy of molecular processes))

98 In Operando Observation for Dynamic Evolution of Pt Nanocatalysts in Pulsed Electrolysis

Pulsed electrochemical method has emerged as a simple and responsive knob to increase catalyst durability and improve product selectivity. However, mechanistic understandings mostly come from traditional experimental techniques or theoretical calculations, only providing ex situ information and preventing accurate analysis of electrode processes. Herein, we developed a novel pulsed modulation XAS (EM-XAS) acquisition system for operando observation of dynamic evolution of Pt nanocatalysts in pulsed electrolysis at molecular level. The near-surface layers of the Pt catalyst are oxidized and reduced periodically with maintained metallic core structure in pulse chemistry. Besides, the oxidation state could be tuned by varying parameters, containing pulse potential and during times. The present study provides a new mechanism of the pulse electrochemistry reaction, and the strategy developed in this work offers a promising approach to unravel the reaction mechanisms of diverse and complex pulsed process.

Speaker: Huan Huang (Institute of High Energy Physics)

ABSTRACT-huang.docx

99 Sub-10nm Hard X-ray Transient Grating and its Application in Crystalline Samples

Atomic collective motions on the sub-10 nm length scales in condensed phase samples, including crystals, glasses, and liquids, are of significant interests for both applications including heat management in information technology, and fundamental research such as glass heat capacity anomalies. While transient grating (TG) with conventional lasers has been widely utilized to measure macroscopic heat dissipation dynamics, and EUV free electron laser (FEL) based TG has been used to measure collective excitations on the length scales of a few tens of nanometers [1], for sub-10 nm length scales, a direct observation of the atomic collective motion has been very challenging.

To resolve this technical challenge, we combine the hard X-ray split-delay optics (SDO) at the X-ray Pump Probe instrument at LCLS with total reflection mirrors and demonstrate the capability of generating TG with a period of 5 nm with 9.5 keV hard X-ray pulses. The TG signal is measured with diffuse scattering from a third X-ray pulse with the same photon energy and a controlled delay time between 0 to 14 ps with a time resolution of 10 fs. Due to the complexity of the optics, a digital twin of this setup is implemented to analyze the installation accuracy requirement, alignment procedure, and TG visibility with the simulated electric field. By adjusting optics, we perform TG measurement with periods of 5, 10, 20, and 50 nm on a series of crystalline samples, including STO and Ge in Bragg geometry. The measured signal is compared with our previous X-ray pump X-ray probe measurement on the same sample.

Reference:

[1] F. Bencivenga, et al., Sci. Adv., 5.7 (2019): eaaw5805.

Speaker: Haoyuan Li (Department of Mechanical Engineering, Stanford University)

Mikrosymposium 2/3: Beamline Innovations: MS2/3

100 The combined soft and hard x-ray beamlines in SSRF and applications in the energy chemistry

With the increasing demands of in-situ/operando spectroscopy investigations of energy mateirals with the high energy resolution, it is substantially vital to setup a beamline in SSRF with the wide energy range and high energy resolution. Consequently, the Energy Material beamline (E-line), spanning soft and hard x-ray with the photon energy from 130 eV to more than 18 keV, has been succussfully constructed in SSRF. Focus on the surface/interface/bulk physics and chemistry in catalysis, energy conversion and energy storage, E-line holds rich spectroscopy techniques: Resonant Elastic scattering Spectroscopy(REXS), Resonant Inelastic X-ray scattering (RIXS), (resonant)X-ray emission spectroscopy(R/XES), X-ray Raman scattering spectroscopy, Ambient pressure X-ray photoemission spectroscopy (AP-XPS), and Hard X-ray photoemission spectroscopy (HAXPES). Key issues of interfacial/bulk atomic fine structures and electronic structures/evolution are unfolded during reactions, including occupied, valence band and unoccupied states. With the layer-by-layer detection abiltiy via varying photon energies, it is expected more sciences of energy materials can be discovered in E-line in the future.

Speaker: Fei Song (SSRF)

101 Commissioning Results of the SAPOTI Cryogenic Nanoprobe at the CARNAÚBA Beamline at Sirius/LNLS

SAPOTI will be the second nanoprobe to be installed at the CARNAUBA (Coherent X-Ray Nanoprobe Beamline) beamline at the 4th-generation light source Sirius at the Brazilian Synchrotron Light Laboratory (LNLS) [1]. Working in the energy range from 2.05 to 15 keV, it has been designed for simultaneous multi-analytical X-ray techniques, including absorption, diffraction, spectroscopy, fluorescence and luminescence, and imaging in 2D and 3D. Highly-stable fully-coherent beam sizes between 30 and 120 nm, with monochromatic flux up to 1e11ph/s/100-mA/0.01%BW, are expected with an achromatic KB (Kirkpatrick-Baez) focusing optics, whereas a new in-vacuum high-dynamic cryogenic sample stage has been developed aiming at single-nanometer resolution images via high-performance 2D mapping and tomography [2].
A Loading Chamber (Figure 1) was designed to: i) preserve the vacuum level and cleanliness of the Main Chamber, with the KB system and a cryogenic nanopositioning sample stage, and ii) store up to six samples in cryogenic condition (around 100 K), using a Pulse Tube Cryocooler, in a carousel with an angular range of about 75°. The samples are preliminarily loaded in the Loading Chamber using a load-lock system (VCT500 Leica Microsystems) and a customized sample cartridge, which can carry up to three samples and gets engaged in the carousel. Then, for sample loading, a linear stage with a custom cryogenic gripper based on thermal inertial, gets a sample and goes toward the sample stage in the Main Chamber through an embedded gate valve, designed to separate the environments and with a 40mm diameter opening for the gripper tip. The key advantages with this cryogenic design are: i) the independence of complex liquid nitrogen circuits and infrastructure, ii) the avoidance of long conductive straps, which might be prone to fatigue and wear, including the release of particle debris on the sample and mirrors; and iii) compliance with high-throughput possibilities, given a loading-time target of a few tens of seconds, and robust and redundant automation. The overall alignment budget and the temperature-related limited amount of time required for this procedure were the biggest technical challenges for this project. This work presents the mechanical design, thermal models, alignment requirements, automation and operational procedures, including the assembly and offline commissioning results.
[1] Tolentino, H.C.N. et al., (2023). J. Electron Spectrosc. Relat. Phenom. 226 (147340).
[2] Geraldes, R.R. et al., (2023). AIP Conf. Proc. 2990 (040017).

Speaker: Renan Ramalho Geraldes (BRAZILIAN SYNCHROTRON LIGHT LAB - LNLS/CNPEM)

SRI2024_abstract_SAPOTI_LoadingChamber_fig1.PNG

102 POLYX: a new compact beamline at SOLARIS for X-ray microimaging and microspectroscopy in the 4 – 15 keV energy range

POLYX is a newly constructed compact bending magnet beamline at the SOLARIS National Synchrotron Radiation Centre in Kraków. The design of POLYX was motivated by the high demand among Polish synchrotron radiation users for experiments at hard X-ray energies. The operating range of POLYX, 5 – 15 keV, is well above the 2 keV critical energy of the 1.5 GeV SOLARIS source. To compensate for the relatively low flux of the SOLARIS bending magnet at higher energies, POLYX can utilize polychromatic X-rays and achromatic polycapillary and monocapillary optics for efficient X-ray focusing.
A water-cooled hybrid double multilayer/Si(111) monochromator with a constant offset is used to generate beams with bandwidths of 2% and 0.02%, respectively. Due to the short length of the beamline (source-to-sample distance equal to 14.5 m), compact achromatic polycapillary and single-bounce monocapillary optics are used to achieve beam spot sizes ranging from approximately 3 µm to 100 µm. The end-station (Figure 1) is designed for micro-XRF mapping, micro-XAS spectroscopy, and micro-tomography experiments.
Switching between focused and unfocused beams can be performed within several seconds, and switching between white or monochromatic modes in several minutes. White beam commissioning of the beamline was carried out in 2022 [1], and the monochromator was commissioned in 2023. Since fall 2023, POLYX has supported user experiments in what is referred to as expert commissioning mode. Regular experiments are scheduled to start in fall 2024.
In this talk, the performance of the beamline will be presented along with the results of the first user experiments. Development plans related to multibeam X-ray imaging will also be discussed [2].
We acknowledge the support of Polish Ministry and Higher Education ( "Support for research and development with the use of research infra-structure of the NSRC SOLARIS” , 1/SOL/2021/2)

[1] . M. Sowa, P. Wróbel, T. Kołodziej, W. Błachucki, F. Kosiorowski, M. Zając, P. Korecki, PolyX beamline at SOLARIS—Concept and first white beam commissioning results, Nuclear Instruments and Methods in Physics Research Section B 538, 131 (2023)
[2] K. M. Sowa, B.R. Jany, P. Korecki, Multipoint-projection X-ray microscopy, Optica 5, 577 (2018).

Figure 1. Experimental table at POLYX. The beamline enables micro-XRF mapping, micro-XAS spectroscopy as well as micro-tomography experiments. Beam focusing is achieved by compact polycapillary and monocapillary optics.

Speaker: Tomasz Kolodziej (SOLARIS, Jagiellonian University)

Figure1.jpg

103 Highlights of the X-ray Nanoprobe CARNAÚBA Beamline at the SIRIUS/LNLS

This contribution presents the main developments and science outcomes of the CARNAÚBA X-ray nanoprobe beamline, recently installed at the new SIRIUS 4th-generation synchrotron source at the Brazilian Synchrotron Light Laboratory (LNLS). The beamline has operated since November 2020 for technical and scientific commissioning and since 2022 for standard user proposals. Its design uses high-resolution multi-analytical and coherent X-ray imaging techniques over the energy domain of 2.05 to 15 keV. An all-achromatic mirror-based optics provides the nano-focused beam. The normal beamline operation employs a monochromatic beam in a high-energy resolution mode using a 4-bounce Si(111) crystal monochromator [1].
The first nanoprobe station, TARUMÃ, provides diverse sample environments for in situ, operando, cryogenic, and in vivo experiments. The sample environment is raster-scanned through the nanoprobe to generate fast two-dimensional maps of simultaneous contrasts, which can then be combined with a rotation for computed tomography. The performance has attained the main specifications, with the predicted flux of 1010 photons/s/100-mA/0.01%BW and a focus size of 180x180 nm2, measured at 10 keV in fluorescence and transmission modes. X-ray ptychography with a monochromatic beam provides a resolution down to 12 nm.
We will briefly discuss the main technical characteristics of the X-ray nanoprobe instrument, emphasizing the first deployed experimental station, TARUMÃ, and showcases results in a broad range of areas that benefit from diverse sample environments. Research domains like photovoltaics, photonics, electrocatalysis, geoscience, and environment are investigated from the viewpoint of chemistry, atomic structure, morphology, and redox dynamics phenomena covered by the beamline techniques [2-6].
[1] H.C.N. Tolentino, et al., The CARNAÚBA X-ray nanospectroscopy beamline at the Sirius-LNLS synchrotron light source: developments, commissioning, and first science at the TARUMÃ station, J. Electron Spectros. Relat. Phenom. 266 (2023) 147340.
[2] I.T. Neckel, et al, Development of a sticker sealed microfluidic device for in situ analytical measurements using synchrotron radiation, Sci Rep. 11 (2021) 23671.
[3] J.A. Barbosa, et al, Biocompatible Wearable Electrodes on Leaves toward the On-Site Monitoring of Water Loss from Plants, ACS Appl Mater Interfaces. 14 (2022) 22989.
[4] G.C. Sedenho, et al, Investigation of Water Splitting Reaction by a Multicopper Oxidase through X‐ray Absorption Nanospectroelectrochemistry, Adv Energy Mater. 12 (2022) 2202485.
[5] R. de Oliveira, et al, High throughput investigation of an emergent and naturally abundant 2D material: Clinochlore, Appl Surf Sci. 599 (2022) 153959.
[6] V. C. Teixeira et al., X-ray excited optical luminescence at Carnaúba, the Sirius X-ray nanoprobe beamline; Optical Materials: X 20, 100278 (2023).

Speaker: Hélio Tolentino (BRAZILIAN SYNCHROTRON LIGHT LAB - LNLS/CNPEM)

104 A Next-Generation Hard X-ray Microscope for Sub-10 nm Imaging: 2D MLL optics for Rapid Nano-Tomography

We have developed a next-generation scanning X-ray microscope RASMI (RApid Scanning Microscopy Instrument) for high-throughput tomographic imaging. RASMI is installed at the Hard X-ray Nanoprobe (HXN) beamline at NSLS-II, and is capable of housing 1D multilayer Laue lenses (MLLs) and 2D optics (both zone plates and monolithically assembled 2D MLLs). The sample scanning stage utilizes line-focusing interferometry as an encoder while performing fly-scanning data acquisition. During the presentation, technical details of the system, including fly-scanning architecture and implementation, will be discussed. In addition, a brief introduction and review of the developed 2D MLL structures will be provided along with the details of design, assembly, and characterization of MEMS-based 2D MLLs. Lastly, we will demonstrate a successful collection of a nano-tomography dataset, where a microelectronics sample of 2 m diameter and 3m height has been imaged within 1 hour with sub-10 nm pixel size and data acquisition rate of 625 Hz. RAMSMI can be adopted for in-vacuum applications and will become a foundation for the next-generation microscopy systems to be developed and commissioned at NSLS-II.

Speaker: Evgeny Nazaretski

SRI_2024_Abstract_final.docx

105 The Mechanical Design and Construction of Transmission X-ray Microscopy (TXM) Endstation at TPS 31A2

The Transmission X-ray Microscope (TXM) endstation at the Taiwan Photon Source (TPS) shares similar functionalities with the Projection X-ray Microscope (PXM) endstation. Both endstation serve as potential scientific tools for micro-computed tomography (micro-CT) and prove invaluable for non-destructive industrial inspections.The TXM endstation's foundation diverges from the conventional approach by being situated on the second layer, approximately 150 mm lower than the standard ground level. This strategic placement provides the benefit of mitigating environmental vibrations arising from various activities, such as human movement, pump operation, and other sources of ground-related vibrations.The TXM endstation comprises seven major modules: (1) Beam stop module, (2) Condenser stage, (3) Aperture module, (4) Sample system, (5) Zone plate stage, (6) Berten lens module, and (7) TXM base stage. Additionally, the wobble of the rotary stage is monitored using two sets of laser interferometers and a specially crafted diamond-turned reflective mirror. One set of laser heads gauges horizontal variations in the rotary stage,while the other detects shifts along the x-axis.

Speaker: Bo-Yi Chen (National Synchrotron Radiation Research Center (NSRRC))

SRI 2024_BYChen_Abstract_Rev02.docx

106 Demand on Advanced Operando Characterization on Industrial Relevant Catalysts Using Combination of X-rays Based and Other Methods

Advanced operando techniques like X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) are powerful tools in field of catalysis to observe structural changes [1]. Certain limitations in catalyst mass, product formation and/or applicable pressure and temperature has to be considered. To extend the portfolio of reactions that can be investigated operando an infrastructure within CAT-ACT beamline at KIT Light Source [2] that allows using a high catalyst mass, high pressure and elevated temperatures is developed.

The key to achieve a substantial reduction of CO2 emissions is the use of renewable energy resources. One scenario is to produce sustainable energy carriers based on green H2 generated via water electrolysis and CO/CO2 provided via "carbon capture" processes or from local CO2-emission sources. One promising approach for renewable energy storage is “Power-to-Liquid” concept (www.spp2080.org). For instance, methanol is mostly produced from a fossil syngas as feedstock (CO, CO2 and H2), using a Cu/ZnO/Al2O3 catalysts (CZA). Switching to pure CO2 brings new challenges as CO2-hydrogenation is thermodynamically less favored compared to CO one, leads to higher water formation and deactivate the CZA catalyst. Using the approved high-pressure and high catalyst mass cell [3] the deactivation of the CZA catalysts were studied under industrial relevant conditions and the role of promoters [4] is uncovered. The hydrocarbons as a basic for the aviation fuel can be produced via Fischer-Tropsch synthesis (FTS) using suitable catalysts [5,6]. With adapted setup operando XAS and XRD studies during FTS were conducted. This studies served as a basis for the successful cooperation in frame of CARE-O-SENE consortium (https://care-o-sene.com/en) for the development of cobalt-based FT catalysts for production of sustainable aviation fuel (SAF). As a carbon-free energy carrier, H2 can be produced by reforming of methane [10]. The main drawbacks of common Ni based catalysts are coke deposition and sintering due to the high temperatures. The suitable continuous flow reactor was developed [13] and role of the Pt promoter was studied using the combination of XAS, XRD and Raman spectroscopic methods. This project has received funding from the EU Horizon 2020 Research and Innovation program (https://www.bike-msca.eu/).

The development of the specified catalytic setup suitable for the advanced operando methods is essential for systematic studies and together with dedicated synthesis could close the knowledge gap between the fundamental research and industrial application.

[1] K.F. Kalz, R. Kraehnert, M. Dvoyashkin, … J.-D. Grunwaldt, J.-D. et al., ChemCatChem 9, 17 (2017)
[2] A. Zimina, K. Dardenne, M. A. Denecke, … J.-D. Grunwaldt et al, Rev. Sci. instrum. 88, 113113 (2017)
[3] M. Loewert, M.-A. Serrer, T. Carambia, … J.-D. Grunwaldt et al., React. Chem. Eng. 5 1071 (2020)
[4] F. Studt, I. Sharafutdinov, F. Abild-Pedersen, … J. K.Nørskov et al, Nat. Chem. 6, 320 (2014)
[5] P.B. Webb, I.A. Filot, in: Reference Module in Chemistry, Molecular Sciences and Chemical Engineering, Elsevier, 2021.
[6] D. Moodley. et al., in: Catalysis for Sustainable Aviation Fuels: Focus on Fischer‐Tropsch Catalysis. Catalysis for a Sustainable Environment: Reactions, Processes and Applied Technologies, 73-116 (2024)
[10] J. Mogensen J.-D. Grunwaldt, P. V. Hendriksen … K. Dam-Johansen et al., J. Chem. 2014, 710391 (2014)
[13] D. Eggart, A. Zimina, G. Cavusoglu, … J.-D. Grunwaldt at al., Rev. Sci. Instrum. 92 (2), 023106 (2021)

Speaker: Anna Zimina (KIT)

Abstract_Zimina_operandoXAS_SRI24.pdf

Mikrosymposium 6/1: FELs: New facilities and Opportunitites: MS6/1

107 Status of the EuXFEL

Hard X-ray Free Electron (XFEL) lasers produce extremely intense and ultra-short X-ray pulses, perfect for investigating the structure and dynamics of matter at atomic length and time scales. Operating for over a decade, these lasers have demonstrated a wide range of applications in physics, chemistry, materials science, and structural biology.

The European XFEL, one of the latest large-scale research infrastructures in Europe, has recently celebrated five years of successful user operations. The facility features a 3.5 km long tunnel, including a 2 km long superconducting accelerator, stretching from DESY in Hamburg to Schenefeld in Schleswig-Holstein, where the experimental hall houses seven instruments. These instruments offer a broad range of experimental capabilities.

Since beginning operations, numerous exciting user experiments have been conducted in fields such as physics, chemistry, bio-crystallography, and material science. In my talk, I will present the main principles of the science performed at the European XFEL, with a focus on high energy density science. I will also provide examples from recent experiments in various scientific areas.

Speaker: Thomas Feurer (Eur.XFEL (European XFEL))

108 FEL machine development and experiments

The FERMI free-electron laser (FEL) facility has recently reached an important milestone with the successful implementation of the echo-enabled harmonic generation (EEHG) scheme in the FEL-1 amplifier line. The maximum photon energy of FEL-1 has been doubled and the spectral quality of this FEL has been significantly improved. FERMI FEL-1 is now the first FEL operating in the 20-10 nm spectral range using the EEHG scheme for user applications. In this communication we review some of the operating modes and recent experiments carried out at FERMI before the upgrade and the prospects offered by the new EEHG configuration, which is part of a wider upgrade strategy to extend the spectral range of the facility to cover the water window and beyond.

Speaker: Luca Giannessi (Elettra - Sincrotrone Trieste S.C.p.A.)

SRI_GIANNESSI.pptx

109 Background-Free Intensity Autocorrelation Measurements for Hard X-ray Free-Electron Lasers Using Second Harmonic Generation in Diamond

Pulse duration of X-ray free-electron lasers (XFELs) is a key parameter for measurements with XFEL pulses. Recent efforts have enabled a direct diagnostics of pulse duration of XFEL pulses thorough an intensity autocorrelation (IAC) technique using two-photon absorption (TPA) [1] where two XFEL pulse replicas are mixed on a metal thin foil as the TPA medium, and then the nonlinear TPA signal intensity (that is here the yield of X-ray fluorescence following TPA) is measured as a function of the time delay between the two replicas. The TPA method has some issues: (1) incoherent nature of TPA where the signal is spread over 4π and insensitive to the phase of the incident wave, (2) inevitable background signals from individual pulse replicas, and (3) a destructive manner where the TPA medium has to be scanned fast enough to illuminate fresh areas shot-by-shot.
To overcome the above issues, we demonstrated another IAC technique with phase-sensitive second harmonic generation (SHG) in a single-crystal diamond at SACLA. The signal of SHG is concentrated in a narrow angular range because of a narrow phase-matching condition of the order of 100 µrad or less [2]. Although the narrow condition typically makes the measurement difficult, it is made possible to eliminate the constant background from individual replicas even on an almost collinear geometry with a tiny angular mismatch of sub-mrad between the two replicas. Furthermore, non-destructive measurements can be realized owing to the radiation hardness of diamond crystals. Through this scheme, we successfully measured autocorrelation traces without constant base at 10 keV. Also, the results clearly showed the difference in autocorrelation traces with and without a Si(311) monochromator, indicating a promising way towards temporal tailoring of XFEL pulses through Bragg diffraction in perfect crystals.
[1] T. Osaka et al., Phys. Rev. Research 4, L012035 (2022).
[2] S. Shwartz et al., Phys. Rev. Lett. 112, 163901 (2014).

Speaker: Taito Osaka (RIKEN SPring-8 Center)

110 Switchable X-ray OAM from a Free-Electron Laser Oscillator

X-ray vortices carrying tunable Orbital Angular Momentum (OAM) are an emerging tool for X-ray characterization technology. However, in contrast to the generation of vortex beams in the visible wavelength region, the generation of X-ray vortices in a controlled manner has proved challenging. Here, we demonstrate an X-ray free-electron laser oscillator (XFELO) can adjust only the kinetic energy of the electron beam to produce vortex beams that can be programmed to dynamically change between different OAM modes, without the need for additional optical elements. With the nominal parameters of currently constructing 1 MHz repetition rate facility (i.e. SHINE), the active formation of the OAM modes of l = ±1 and l = ±2 and the rapid switching between them by detuning the electron beam energy of the XFELO are numerically illustrated. The real-time switching can be achieved within 200 μs, while the output pulse energy can reach the 100 μJ level. This result extends the capabilities of XFELOs, and paves the way for advanced at-source applications using X-ray vortex beams.

Speaker: Nanshun Huang (Shanghai Optoelectronic Science and Technology Innovation Center)

111 LCLS-II Gas Based Intensity and Spectral Diagnostics for the Soft X-ray Range

Marcio Paduan Donadio, Marc Campell, Vincent Esposito, Philip Heimann, Dawood Alnajjar, Yuantao Ding, Thi Le, Alberto Lutman, Heinz-Dieter Nuhn, William Schlotter, Jan Gruenert, Kai Tiedtke, Fini Jastrow, and Stefan Moeller
Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025, United States
* European XFEL, Holzkoppel 4, Schenefeld, 22869, Germany
*Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany

The LCLS-II superconducting accelerator has started operations after successful commissioning last August/September of 2024. Some of the initial performance parameters are photon energy range from 250 eV to 3.8 keV and a maximum repetition rate of 1 kHz. In the soft x-ray energy range (250-1000eV) we used a set of Gas-based Monitor Detectors (GMD) to measure first lasing photons and to transition to operations. Besides providing FEL intensity measurements we calibrated the photon energy and FEL bandwidth with a simple method by using a pair of GMDs while scanning the undulator gap. Results in the soft x-ray range are presented that complement the results in the hard x-ray range.

Speaker: Stefan Moeller (SLAC)

112 RF Direct Sampling Processor Brings Revolutionary Progress to Beam Diagnostics

Analog down-conversion structures have been used for beam diagnostics, especially in the processing of GHz frequency signals such as cavity BPM/BAM and bunch-by-bunch feedback. But the RF front-end module in the structure contains a large number of analog devices, which reduces the system performance, complicates the system, difficult to design and cost much. Digitizing the RF signal directly and processing them in the digital domain has always been our goal. For the first time, we have developed an RF direct sampling processor for cavity BPM/BAM systems in XFEL. The processor bandwidth reaches 6GHz and sampling rate 2.6GSPS, no front-end module needed and gets better performance compared to analog down-conversion structure. This is a stand-alone processor that enables complete cavity pickup signal processing. It can meet the signal processing needs of different of cavity pickups and also can be used in bunch-by-bunch feedback system on synchrotron radiation facility. It brings great progress to the beam diagnostics of XFEL and synchrotron radiation facilities.

Speaker: Longwei Lai (Shanghai Advanced Research Institute, Chinese Academy of Sciences)

113 Tunable-Bandwidth Monochromator for Hard X-rays with Wavefront Preserving Crystal Optics

A new monochromator concept has been developed that allows tuning the bandwidth of the hard X-rays. The design is based on the 4f Fourier pulse shaping principles used in the table-top optical laser field. Very briefly, the X-ray beam is spatio-spectrally dispersed at the Fourier plane, where high-precision slits define the bandwidth that is encoded along the dispersive direction. The monochromator spans a 40-meter space along the beam path, which is required to achieve the necessary resolving power and to recover the transform-limited pulse durations without wavefront tilt or distortions.

The monochromator covers a wide spectral range between 5 keV and 20 keV without swapping crystals and delivers a tunable bandwidth as narrow as a few meV across the entire range. The upper boundary of the continuously tunable bandwidth range is between a few tens of meV and hundreds of meV, depending on the photon energy. This monochromator will be supporting the inelastic X-ray scattering and X-ray photon correlation spectroscopy experiments after the LCLS-II-HE upgrade at SLAC National Accelerator Laboratory in California.

Speaker: Hasan Yavas (SLAC National Accelerator Laboratory)

13:00 Lunch Break

114 Lunch seminar: DECTRIS - Cloud Launch

115 Lunch seminar: Lightsources.org - Careers lunchtime session

Your opportunity to pose career questions to some of the most successful professionals in the light source community
Isabelle Boscaro-Clarke, Diamond Light Source (Chair)
Laurent Chapon, Argonne’s Associate Laboratory Director for Photon Sciences and director of the APS
Gianluigi Botton, CEO, Diamond Light Source
Sakura Pascarelli, Scientific director at European XFEL
Gerd Materlik, Emeritus Professor at UCL, former CEO of Diamond and former Head of HASYLAB at DESY and later Deputy Director

14:00 Poster Session incl. Coffee

116 Computed X-ray microtomography

Ptychography is a coherent lensless imaging technique that incorporates scanning of the sample. As such, it relies heavily on computations and has benefitted from advances in algorithms since its original conception in 1969 [1] and its more modern iterative implementation from 2004 [2]. Leveraging the coherence of X-ray sources, it does away with imaging lenses and their limitations in resolution and efficiency, that are inherent to their challenging manufacturing. It has been shown to work with perfect as well as aberrated, or partially coherent, illuminations, as well as being able to correct for multiple scattering effects, and even figure out and correct for inaccurate positioning of the sample due to scanning-stage errors.
It may seem that for ptychography all that matters is the reconstruction algorithms and all instrumental errors and other imperfections can be accounted for in post-processing. This is to some extent true due to the richness of information in a ptychogram. However, these postprocessing corrections come at the cost of signal-to-noise ratio, or in other words, of photon statistics. Joint improvements both in algorithms and instrumentation can yield significantly more efficient imaging.
Years of research into optimizing ptychographic tomography [3, 4] have led to important advances in instrumentation that enable high throughput and resolution. These include using optical interferometry for accurate sample positioning, design X-ray illuminations with engineered wavefront aberrations, and implementing hybrid scanning approaches of optics and sample. In this presentation I will showcase some important advances in instrumentation as well as algorithms that have allowed a sustained improvement in imaging throughput at the cSAXS beamline of about 3 times per year over 10 years.
References
[1] W. Hoppe, "Beugung im inhomogenen Primarstrahlwellenfeld. I. Prinzip einer Phasenmessung von Elektronenbeungungsinterferenzen," Acta Crystallographica Section A 25, 495-501 (1969). https://doi.org/doi:10.1107/S0567739469001045
[2] H. M. L. Faulkner and J. M. Rodenburg, "Movable aperture lensless transmission microscopy: A novel phase retrieval algorithm," Physical Review Letters 93, 023903 (2004). https://doi.org/10.1103/PhysRevLett.93.023903
[3] M. Holler, M. Guizar-Sicairos, E. H. R. Tsai, R. Dinapoli, E. Müller, O. Bunk, J. Raabe, and G. Aeppli, "High-resolution non-destructive three-dimensional imaging of integrated circuits," Nature 543, 402-406 (2017). https://doi.org/10.1038/nature21698
[4] M. Holler, M. Odstrcil, M. Guizar-Sicairos, M. Lebugle, E. Müller, S. Finizio, G. Tinti, C. David, J. Zusman, W. Unglaub, O. Bunk, J. Raabe, A. F. J. Levi, and G. Aeppli, "Three-dimensional imaging of integrated circuits with macro- to nanoscale zoom," Nature Electronics 2, 464-470 (2019). https://doi.org/10.1038/s41928-019-0309-z

Speaker: Manuel Guizar-Sicairos (PSI/EPFL)

Abstract.pdf

16:00 Break

Mikrosymposium 10/2: New Lattices and IDs: MS10/2

117 IVU-II: high-performance and cost-effective in-vacuum undulator for SPring-8-II

In-vacuum undulators (IVUs), in which permanent magnets are placed inside the
vacuum chamber to allow for a narrower gap operation, have two technical
challenges; one is a strong attractive force between acting on magnetic arrays,
and the other is a stringent requirement on magnetic materials to avoid
demagnetization during the bake-out process and long-term operation. The former
imposes a complicated design on mechanical and vacuum structures, while the
latter limits the possibility of using permanent magnets with high remanence. To
solve these issues, several technical developments have been made, such as the
force cancellation, modularization of magnetic arrays, and enhancement of
resistance against demagnetization by means of a special magnetic configuration.
In this talk, performances of new IVUs built upon these technologies are
presented to reveal their effectiveness for constructing high-performance IVUs
in a cost-effective manner.

Speaker: Takashi Tanaka (RIKEN SPring-8 Center, Japan Synchrotron Radiation Research Institute)

118 Lattice for the SOLEIL II Upgrade

In order to continue to provide world-class capabilities and cutting-edge tools to support scientific endeavors, SOLEIL launched its upgrade program, known as SOLEIL II, in 2020. This project is based on a very aggressive accelerator design aiming at an ultra-low emittance of about 80 pm.rad at 2.75 GeV, providing a 10 m RMS round electron beam and more than 100 times brighter photon beams. This performance is based on the use of a circular copper vacuum chamber with an inner diameter in the arcs as small as 12 mm fully NEG coated, which enables the achievement of strong quadrupole gradients (120 T/m) and very strong sextupole strengths (8500 T/m2). These technical challenges have pushed engineering technologies to their limits and their validation has required an intensive R&D program. The project also relies on innovative developments such as a new high-performance non-linear kicker and new insertion devices together with extensive use of permanent magnets. We believe that the choices used and validated in our project represent a new paradigm in storage ring design that we would like to share at this conference.

Speaker: Amor NADJI (SYNCHROTRON SOLEIL)

119 The PETRA IV Machine Project

DESY is planning a major upgrade of the existing PETRA III synchrotron light source to an ultra-low emittance ring PETRA IV

We describe the status of machine project with highlights on the expected performance, a description of the main subsystems,

and the current prototype programme.

Speaker: Riccardo Bartolini (MPY (Beschleunigerphysik))

Bartolini_PIV-MProjectRep_SRI_2024_08_28.pptx

120 A Bi-Periodic Undulator for SOLEIL II: The Prototype and the First Beam Tests at SOLEIL

The recent improvements in the field of synchrotron light sources push the limits of brightness and pave the way for new scientific research. The upgrade of Synchrotron SOLEIL, called SOLEIL II, aims at optimizing photon production by reducing the natural horizontal emittance of the electron beam to less than 100 pm.rad, compared to 3.9 nm.rad currently. However, the new lattice [1] imposes a 30% reduction in the space reserved for some insertion devices. SOLEIL is presently looking for technical solutions such as compact radiation sources to take into account this space constraint.

An innovative device called “bi-periodic undulator” [2] is studied at SOLEIL. It is a compact device with special magnet arrangement, made of a vertical superimposition of magnet that permits changing the period of the magnetic field [3]. The magnetic period can be changed by its triple value using longitudinal shifting of the magnetic system. Such a capability makes possible the spectral range extension of the undulator by changing the operating mode and permits replacing two juxtaposed undulators by only one insertion device.

We will report on the design, the results of simulation of the magnetic performance, the impacts on beam dynamics and the expected emitted radiation. The construction of the bi-periodic undulator prototype will also be detailed, as well as its magnetic characterization, the applied correction methods and its limits. The installation on the present storage ring and the results from the first beam tests will be presented.

[1] A. Loulergue et al., “TDR baseline lattice for the upgrade of SOLEIL”, in Proc. IPAC’22, Bangkok, Thailand, Jun. 2022. doi:10.18429/JACoW-IPAC2022-TUPOMS004

[2] O. Marcouille, A. Mary, M.-E. Couprie, and K. Tavakoli, Onduleur bi-périodique, dispositif, installation et procédé associé, Patent no. FR3125670. https://patents.google. com/patent/FR3125670A1/

[3] A. Potet et al., « bi-périodic undulator : innovative insertion device for SOLEIL II », in Proc. FLS2023, Luzern, Switzerland, Aug 2023. doi:10.18429/JACoW-FLS2023-TH1D4

Speaker: Angela Potet (Synchrotron Soleil)

121 Advancement of Superconducting Undulators Towards Plug and Play Systems

Speaker: Philipp Revilak (Bilfinger Nuclear and Energy Transition GmbH)

122 Recent Activities of National Synchrotron Light Source-II Insertion Device Group

Insertion Device (ID) Group at the National Synchrotron Light Source-II has been involved in the following activities: Installation and maintenance of the HEX-Superconducting Wiggler (SCW)[1], Development of SC 2T-three pole wiggler (3PW) for NEXT-III project, Laboratory Directed Research and Development (LDRD) for SC adaptive gap undulator (AGU)[2], NSLS-II Experimental Tools II (NEXT-II) project IDs [3]. Improvement of in-vacuum flip coil bench, development of in-vacuum pulsed wire bench and upgrade of regular flip coil bench. This paper describes the specifics of each activity.

References:
[1] Tanabe, T., Hidas, D. A., Musardo, M., Rank, J., Corwin, T., Migliorino, D., Rank, J., Hidaka, Y., Todd, R., Seegitz, M., Breitenbach, M., Hobl, A. and Grau, ”Development of the high energy engineering X-ray (HEX) superconducting wiggler, magnetic measurement, installation, and commissioning”, Review of Scientific Instruments 94, (2023):. https://doi.org/10.1063/5.0146964
[2] O Chubar, J Bengtsson, A Blednykh, C Kitegi, G Rakowsky, T Tanabe, J Clarke, “Segmented Adaptive-Gap In-Vacuum Undulators - Potential Solution for Beamlines Requiring High Hard X-Ray Flux and Brightness in Medium Energy Synchrotron. “ Sources, J Phys.: Conf. Ser., 425, 032005 (2013). [102081]
[3] https://www.bnl.gov/nsls2/beamline-development.php

Speaker: Toshiya Tanabe (Brookhaven National Laboratory)

123 Development of an Elliptically Polarizing X-Type Undulator for Fourth Generation Light Sources

The small beam size at the straight sections of for fourth generation light sources has opened the possibility to use small-diameter circular vacuum chambers for insertion devices. An elliptically polarizing X-type undulator with a small circular vacuum chamber and symmetric placement of the magnet rows around the vacuum chambers is being developed at LBL. This type of undulator is suitable for fourth generation light sources and linac based free electron lasers. Salient features of the X-type undulator include the mechanical construction with compact crossed roller bearings and fully hydraulic motion control system.

Speaker: Erik Wallén (Lawrence Berkeley National Laboratory)

Mikrosymposium 2/4: Beamline Innovations: MS2/4

124 PTB's new microfocus beamline for Tender X-ray dipole radiation at BESSY II with a monochromator combining a multilayer-based PGM and a DCM

In PTB’s laboratory at BESSY II, we have set up a new beamline at a bending magnet. It provides monochromatized radiation in the tender X-rays range from 1.5 keV to 10 keV focused typically to a 20 µm x 20 µm spot.
A new concept has been developed and implemented for the monochromator. It consists of a plane grating monochromator (PGM) with a multilayer-coated blazed grating and plane mirror on the one hand and an integrated double crystal monochromator (DCM) module with two Si(111) crystals on the other hand. Either the PGM (below 3.5 keV) or the DCM module (above 2.45 keV) can be used. Other components of the beamline are a toroidal and a cylindrical mirror for the collimated PGM, a slit system with a horizontal and a vertical slit at the intermediate focus and a Kirkpatrick-Baez optical system with plane-elliptical mirrors. The toroid has a Pt- and a C-coating, while the other mirrors only have a Pt-coating.
The new beamline is intended to increase our beamtime capacity in the tender X-rays range, where the requirements increased significantly and cannot be met anymore with the existing four-crystal monochromator (FCM) beamline. Providing a microfocus will simplify and improve X-ray spectrometric measurements such as µ-XRF (X-ray fluorescence) and XES (X-ray emission spectroscopy) with a von Hamos spectrometer.
Currently, the beamline is in the commissioning phase and will be available for full user operation from August 2024. We will present the concept of the monochromator and the optical design of the beamline. We will discuss the advantages and disadvantages of the concept and the present first results about the performance of the beamline concerning e.g. the available photon flux, the obtained spot size and the spectral purity including the higher order contributions.

Figure: The figure shows the photon flux provided by the new microfocus beamline in PGM and DCM mode at 300 mA ring current. Different coatings of the toroidal mirror and thin metal filters have been used to improve the spectral purity.

Speaker: Matthias Müller (Physikalisch-Technische Bundesanstalt)

SRI2024_Abstract_MMüller_figure.png

125 Synchrotron infrared nanospectroscopy in fourth-generation storage rings

Fourth-generation synchrotron storage rings mark a significant advancement in synchrotron technology, providing exceptionally bright and precisely focused X-ray beams crucial for diverse scientific pursuits. Yet, their tightly configured magnetic lattices historically presented obstacles for accessing lower-energy radiation, like infrared (IR) and THz. Here, we unveil the inaugural IR beamline installed and operational within a fourth-generation synchrotron storage ring. Our efforts encompass several key breakthroughs, including a comprehensive analysis of the new IR source at Sirius, a detailed description of the radiation extraction method, and a validation of our optical framework through meticulous measurements and simulations. This optimized optical configuration has facilitated an impressively broadband range for our nanospectroscopy endeavors. By employing synchrotron IR nanospectroscopy on samples of biological and hard matter, we effectively showcase the practicality and efficacy of this beamline. We underscore the advantages of fourth-generation synchrotron IR sources, now capable of operating with unparalleled stability owing to the exacting standards for generating low-emittance X-rays.

References:
[1]. Santos, T. M., Lordano, S., Mayer, R. A., Volpe, L., Rodrigues, G. M., Meyer, B., Westfahl, H., & Freitas, R. O. (2024). Synchrotron infrared nanospectroscopy in fourth-generation storage rings. Journal of Synchrotron Radiation, 31(Pt 3), 547–556. https://doi.org/10.1107/S1600577524002364

Speaker: Raul de Oliveira Freitas (Brazilian Synchrotron Light Laboratory (LNLS))

abstract_RaulFreitas.pdf

126 Frontiers in Nano-ARPES research at the ALS MAESTRO beamline and outlook towards ALS-U

Angle-Resolved Photoemission Spectroscopy (ARPES) is the premier tool to determine a quantum
material’s momentum-dependent electronic states and their energy and lifetime renormalization due to many-body interactions. Nanoscale ARPES (nanoARPES) has recently greatly expanded the practical reach of ARPES to submicron samples. The MAESTRO nanoARPES instrument at the ALS has achieves ~100 nm resolution and has opened the door to a rapidly growing user community. I will give a brief review of the status and recent work of the nanoARPES program at the ALS and then discuss the future of the program, highlighting the importance of the ALS-U upgrade. Finally, I will introduce a novel approach to push nanoARPES resolution beyond today’s practical limits to a fundamentally new regime, 10 nm and below. This ultimate nanoARPES could open a new frontier for understanding interactions and the electronic structure origin of emergent properties at the length scales where they develop.

Speaker: Aaron Bostwick (Lawrence Berkeley National Laboratory)

127 Towards Tender X-rays by Means of Multi-Layer Coated Gratings as Monochromator Optics

State-of-the-art soft X-ray beamlines use collimated plan-grating monochromators (cPGM) [1] as monochromatizing devices. Multi-Layer (ML) coated plane gratings and mirrors allow to extend the available photon energy range of cPGM’s towards the so-called tender X-ray photon energy range (up to 5 keV) providing a significantly higher photon flux [2]. This X-ray energy regime covers L- and M-absorption edges of most of the transition and rare-earth metals as well as K-edges of lighter elements such as silicon, sulfur and phosphorus. Recently such a ML based monochromator setup became operational at the U41-PGM1-XM beamline at the BESSY-II storage ring in Berlin [3]. This beamline upgrade enabled high resolution spectro-microscopic applications using photon energies up to 3keV. And extend its possibilities to support research e.g. on the field of life-science, semiconductor development and battery research. We will report on the design, commissioning and performance of this beamline and discuss possible options for new developments on the field of beamlines and end-stations in the tender-X-ray energy range (up to 5keV) at existing and future new accelerator-based photon sources.

1 Rolf Follath, Friedmar Senf, “New plane-grating monochromators for third generation synchrotron radiation light sources”, Nucl. Instr. and Meth. in Phys. Res. A 390 (1997) 388-394
2 A. Sokolov, Q. Huang, F. Senf, J. Feng, S. Lemke, S. Alimov, J. Knedel, T. Zeschke, O. Kutz, T. Seliger, G. Gwalt, F. Schäfers, F. Siewert, I. V. Kozhevnikov, R. Qi, Z. Zhang, W. Li, and Z. Wang, “Optimized highly-efficient multilayer-coated blazed gratings for the tender X-ray region” Opt. Express 27(12), 16833–16846 (2019)
3 Stephan Werner, Peter Guttmann, Frank Siewert, Andrey Sokolov, Matthias Mast, Qiushi Huang, Yufei Feng, Tongzhou Li, Friedmar Senf, Rolf Follath, Zhohngquan Liao, Kristina Kutukova, Jian Zhang, Xinliang Feng, Zhan-Shan Wang, Ehrenfried Zschech, and Gerd Schneider, “Spectromicroscopy of Nanoscale Materials in the Tender X-Ray Regime Enabled by a High Efficient Multilayer-Based Grating Monochromator”, Small Methods 7 (2023), 2201382, DOI: 10.1002/smtd.202201382

Speaker: Frank Siewert (Helmholtz Zentrum Berlin)

128 Commissioning of a Collimated Plane-Grating Monochromator with Ultra-High Resolution and Evaluation by Resonant Auger Spectra

Modern soft x-ray spectroscopies such as resonant inelastic x-ray scattering require stable x-rays with high energy resolution. To realize such a grating monochromator, the state-of-the-art optics have to be installed without any distortion on precise scanning stages in ultra-high vacuum. Their attitude must be precisely aligned by the beam. Instability of photon energy due to vibration and thermal drift can result in reduced energy resolution, so the optical elements must be cooled quietly and efficiently. We have upgraded a soft x-ray monochromator with moderate resolution at SPring-8 into a collimated plane grating monochromator with ultra-high energy resolution of over 30,000 based on the fundamental technologies, including vibration measurement, optical metrology, and beam evaluation.
As shown in Figure 1, a plane grating monochromator with variable line spacing [1] was reconstructed as a plane grating monochromator operating with parallel beams [2]. The advantage of this monochromator is that it always satisfies the focusing condition. Thus, photon energy can be scanned by simply rotating the grating without any reduction in resolution. The optical elements were replaced with state-of-the-art optical components. To reduce the effects of vibration, environmental vibration was minimized and the coolant flow path was optimized using low-vibration flexible tubes.
Collimation and focusing of M0 and M3 respectively are necessary to maintain resolution over a wide energy range. The collimation and focusing conditions of these two mirrors were confirmed by Foucault tests using total ion yield spectra. Misalignment of the mirrors was corrected using the results of ray tracing. The energy resolution was estimated from resonant Auger electron spectra of noble gases. Since the energy width of the excited photon is smaller than the natural width of the core-excited state, the Auger line is not affected by the lifetime width. Therefore, the energy resolution can be estimated with high accuracy in a relatively short time. The energy resolution was estimated to be 39,000 at 867 eV from the Ne resonant Auger spectrum, which is almost the same as the design value.
Details of the upgrade, how the monochromator was adjusted, and the evaluation of the energy resolution will be presented.
[1] Y. Senba et.al, Nucl. Instr. And Meth. A 649, 58 (2011).
[2] R. Follath and F. Senf, Nucl. Instr. Methods A 390, 388 (1997).
Figure 1. Optical layout of a collimated plane-grating monochromator.

Speaker: Yasunori Senba (Japan Synchrotron Radiation Research Institute, RIKEN SPring-8 Center)

129 Tender X-Ray RIXS at PETRA-III

Resonant inelastic x-ray scattering (RIXS) [1] is a momentum resolved x-ray spectroscopy technique that requires high energy resolution around specific atomic absorption edges. This usually means the L2,3-edges of the transition metals (3d, 4d, and 5d TMs) and a resolution on the order of ΔE~50 meV, making it possible to measure spin-waves and atomic multiplets in d-electron systems. However, the L2,3-edges of the 4d TMs compounds – located in the tender x-ray regime (2-4 keV) – are not easily accessible or compatible with operating soft and hard x-ray RIXS instruments. In light of this problem, the Max-Planck Institute in Stuttgart and beamline P01 at Petra III DESY constructed in 2017 a new RIXS instrument dedicated solely to tender x-rays [2]. The instrument, dubbed IRIXS (intermediate x-ray energy RIXS), was originally intended for the Ru L3-edge (2840 eV) [3,4] but has since then been expanded to other 4d edges, including Rh L2,3-edge (3004 and 3146 eV) and Ag L2,3-edge (3351 and 3523 eV), as well as edges beyond the TMs such as U M4,5-edge (3550 and 3725 eV) [5] and S K-edge (2470 eV). Here I will argue that all of this is now possible thanks to our renewed interest in developing and making spherically bent and diced x-ray analysers (quartz [6] and LiNbO3), a work that has been partially carried out in collaboration with the Advanced Photon Source at Argonne [7]. Finally, I will present the IRIXS Spectrograph [8], a concept based on a flat silicon crystal analyser, and show how such a detection scheme can profit from the PETRA-IV project.

[1] Luuk J. P. Ament et al., Rev. Mod. Phys. 83 705 (2011)
[2] H. Gretarsson et al., J. Synchrotron Rad. 27 538-544 (2020)
[3] H. Gretarsson et al., Phys. Rev. B 100 045123 (2019)
[4] H. Suzuki et al., Nat. Commun. 14, 7042 (2023)
[5] A. Marino et al., Phys. Rev. B 108, 045142 (2023)
[6] D. Ketenoglu et al., J. Synchrotron Rad. 25 537-542 (2018)
[7] A. H. Said et al., J. Synchrotron Rad. 25 373-377 (2018)
[8] J. Bertinshaw et al., J. Synchrotron Rad. 28 1184 (2021)

Speaker: Hlynur Gretarsson (FS-PETRA-S (FS-PET-S Fachgruppe P01))

130 Recent Developments in the Soft X-ray RIXS Programme at the ESRF

During the last 5 years the RIXS instrumentation at the ESRF soft X-ray beamline ID32 has undergone a major upgrade which greatly improved the resolution and the through-put of the instrument compared to its first period of operation from summer 2015 to the ESRF-EBS shutdown. This upgrade included the replacement of refocusing optics, spectrometer gratings and also the installation of new undulator sources. At the same time, the arsenal of sample environments available to users has also been continuously developed. In addition to the standard cryogenic sample environment we can now also offer setups for uniaxial strain, high temperatures or electric and magnetic fields to users. In this talk, we will present technical aspects of the various upgrades and sample environments for the high resolution RIXS spectrometer together with commissioning results and examples from user experiments.

In early 2024, the high-resolution RIXS program at ID32 was complemented with a compact, high through-put RIXS spectrometer that is operated at the XMCD branch of the beamline and has seen first user experiments in February and March 2024. This spectrometer is mobile and can be attached to several end-stations: the ID32 high-field magnet for RIXS measurements in fields up to 9T and down to 4K, a compact material science end-station for materials research, and in the future a pulsed field magnet granting access to fields of 50+ Tesla. In the second part of this talk, we will discuss the design of this spectrometer and show commissioning results as well as some first scientific examples of RIXS measurements in high-magnetic fields.

Speaker: Kurt Kummer (ESRF)

Mikrosymposium 5/1: Operando Investigations: MS5/1

131 Development of in-operando capabilities in TPS 19A High-resolution Powder Diffraction beamline

The TPS 19A beamline signifies a substantial leap forward in powder X-ray diffraction (PXRD), providing outstanding capabilities for both static structure determination and studies in structural kinetics across a broad spectrum of crystalline samples, including micro and nano materials, even under non-ambient conditions. Outfitted with state-of-the-art instrumentation such as the cryogenic in-vacuum undulator (CU15) for generating highly collimated X-ray beams, the Double Crystal Monochromator (DCM) for precise energy selection, and a micro-focusing system employing Kirkpatrick-Baez mirrors, the beamline ensures efficient data collection and user interaction through a hybrid EPICS, Bluesky, and Python system. Detectors like the Multi-crystal analyzer, MYTHEN 18K, and XRD 1611 enable high resolution and rapid data acquisition, supporting specialized experiments. Moreover, the beamline's versatility extends to accommodating various sample environments, including high/low temperatures, gas adsorption/desorption, electrochemistry, and high-pressure setups with diamond anvil cells. With a focus on in-situ experiments, researchers can investigate structural dynamics in real-time, thereby enhancing our understanding of material behavior. Furthermore, the integration of X-ray diffraction (XRD) and pair distribution function (PDF) analysis techniques provides a comprehensive approach to characterizing material structures, facilitated by advancements in experimental techniques. Leveraging 30keV high-energy X-rays and the large-angle one-dimensional detector MYTHEN 18K enables simultaneous acquisition of high Q and delta Q resolution data, significantly enhancing the analysis of both crystalline and amorphous materials. Overall, the TPS 19A beamline serves as a beacon of innovation in PXRD research, propelling advancements in materials science and fostering scientific exploration through its advanced capabilities and dedication to comprehensive structural characterization.

Speaker: Yu-Chun Chuang (National Synchrotron Radiation Research Center)

SRI2024_CYC.docx

132 Tender X-ray Photon-In/Photon-Out Spectroscopy at ESRF ID26

The energy range between 1.5 and 4.5 keV (tender X-rays) covers the K-edges of Al, Si, P, S, Cl, K and Ca, the L-edges of 4d transition metals and the M-edges of actinides. 4d transition metals and actinides can also be measured in the hard x-ray range but the smaller lifetime broadening and favorable selection rules to probe the valence orbitals directly make the tender X-ray range interesting also for those elements. X-ray emission spectroscopy (XES) in combination with X-ray absorption spectroscopy (XAS), photon-in/photon-out spectroscopy, can provide sharper spectral features and allows studying the occupied and unoccupied density of electronic states thus providing a wealth of information.
Tender X-ray emission spectrometers have been realized in dispersive and scanning geometries at various synchrotron radiation end-stations and at laboratory X-ray sources. Beamline ID26 at the ESRF features an instrument in non-dispersive, scanning geometry that employs eleven Johansson crystals in combination with a gas proportional counter or a pixel detector [1]. The 80 mm long Si crystal wafers are cylindrically bent to 1m radius in the meridional plane. The sagittal dimension is 25mm requiring a large detector surface of 50 x 25 mm2. The angular range of the instrument is 35 to 85 degrees. This tender X-ray spectrometer (TEXS) is currently by far the most efficient instrument for high-energy-resolution fluorescence-detected (HERFD) XAS studies in the world.
With the energy transition the requests for in situ and operando studies of materials has dramatically grown. Carrying out such studies in the vacuum chamber of the ID26 tender X-ray instrument has thus become a top priority. To this end, an operando cell for catalysis experiments was developed and commissioned [2]. The presentation will present some fundamental considerations for tender X-ray photon-in/photon-out spectroscopy as well as the ID26 spectrometer with the operando cell.
[1] Rovezzi et al. https://doi.org/10.1107/S160057752000243X
[2] Suarez Orduz et al. https://doi.org/10.1002/cmtd.202300044

Speaker: Pieter Glatzel (ESRF)

TenderXray.png

133 Instrumentation to Promote In-Situ Experiments at the Powder X-ray Diffraction Beamline (PAINEIRA) at SIRIUS

PAINEIRA beamline at the SIRIUS synchrotron laboratory in Brazil is a facility dedicated to the X-ray diffraction characterization of polycrystalline materials. In addition to the high photon flux, it presents an arc-shaped 2D detector covering 109° in 2theta (in-house development). These provide high-quality and fast acquisition of the XRD pattern at the beamline, which is suitable for in-situ experiments. Thus, several systems were designed and implemented to enable kinetics while acquiring the structural data. First, two types of capillary cell reactors were projected to be installed on the center of the 3-circle diffractometer of the beamline. One operates for ambient pressure experiments and the other for up to 100 bar. Second, a module (Fig.1 and 2) presenting five mass flow meters, pneumatic valves with automatic actuators, one-way valves, a saturator, a heating system, pressure sensors, and back pressure (Fig. 2) was developed to select and control fluids used in the experiments up to 100 bar. It is installed close to the diffractometer (Fig. 1) and connected to the capillary cells via peek tubes. A vapor phase can be delivered to the experiment through a controlled flow of He, which carries the vapor pressure of a liquid inside the saturator. A liquid phase can be supplied with an injection pump. All fluids can flow through the capillary cell or bypass. A PyQt interface from the beamline controller computer automatically controls the module. Finally, open-source software (Iguape) is being developed to allow instantaneous visualization of the XRD patterns acquired during kinetic or static experiments. Iguape will also plot auxiliary graphs exhibiting the peak position, the full width of the height maximum (FWHM), and the peak area evolution of a specific diffraction peak selected by the user. This set of instruments is a user-friendly system that improves the efficiency of in-situ experiments at the Paineira beamline.

Speaker: Cristiane B. Rodella (LNLS-CNPEM)

PNR_SRI_2024.pdf

134 Algorithm-Accelerated Six-Dimensional WAXD Tensor Tomography

We propose a novel 6D X-ray wide-angle diffraction (WAXD) tensor tomography method which only requires a conventional 3D scanning tomography acquisition protocol. The new method can increase the acquisition efficiency of the 6D WAXD tensor tomography by at least one order of magnitude by fully exploring the hidden 3D reciprocal information in the 2D WAXD pattern.
X-ray scattering/diffraction tensor tomography techniques are promising methods that can acquire the 3D texture information of heterogeneous biological tissues at micrometer resolution. However, the methods suffer from a long overall acquisition time due to the multi-dimensional scanning across the real and reciprocal space. Here we introduce a new approach to obtain 3D reciprocal information of each illuminated scanning volume using mathematical modeling, which is equivalent to a physical scanning procedure for collecting full reciprocal information required for the voxel reconstruction. The virtual reciprocal scanning scheme was validated by a simulated 6D WAXD tomography experiment. The theoretical validation of our method represents an important technological advancement for the 6D diffraction tensor tomography and a crucial step toward pervasive applications in the characterization of heterogeneous materials.

Speaker: Zheng Dong

135 The Nano-Diffraction Instrument of the NanoMAX Beamline at MAX IV

The nano-diffraction instrument was the first nanoprobe endstation of the NanoMAX beamline at MAX IV and has been in user operation since 2017 [1]. It is based on a diffraction-limited KB mirror system with a long working distance of 100 mm and delivers a highly coherent nano-focused beam down to 40-200 nm, depending on the photon energy [2,3]. The alignment of the KB mirrors is routinely verified and adjusted based on the ptychographic reconstruction of a lithographic test structure [3,4]. The sample alignment is facilitated by a two-circle goniometer, a set of custom-built, long-stroke XYZ positioners, and a high-load XYZ piezo scanner. The entire sample positioning stack is optimized to accommodate sample environments weighing of up to 1000 g. In-situ optical microscopes, providing both on-axis and top-view perspectives, that assist in pre-aligning samples within the X-ray focus. A pixel detector inside an evacuated flight tube measures the forward-scattered signal. A robotic arm allows for the flexible positioning of a state of the art pixel detector in 3D for coherent diffractive imaging or Bragg ptychography [5]. Wide-angle scattering experiments can utilize a large-area detector positioned near the sample. The fluorescence signal emitted by the samples is captured by an energy-dispersive detector. The instrument is frequently used for experiments involving samples environments such as nano-indenters [6], electro-chemistry cells, XBIC setups [7], heaters, high-pressure cells [8], or other user-supplied setups.
We will present its capabilities, recent instrument improvements and upgrades, current sample environments, and results of selected user experiments.

Keywords: Nanoprobe, Ptychography, Cohrent Diffractive Imaging, Nano-Diffraction, X-Ray Fluoresecnce.

References
[1] D. Carbone, et al., Journal of Synchrotron Radiation, 29 (2022), 876-887, doi: 10.1107/S1600577522001333
[2] U. Johansson, et al., Journal of Synchrotron Radiation, 28 (2021), 1935-1947, doi: 10.1107/S1600577521008213
[3] A. Björling, et al., Opt. Express 28, (2020), 5069-5076, doi: 10.1364/OE.386068
[4] M. Kahnt, et al., Opt. Express 30 (2022), 42308, doi: 10.1364/OE.470591
[5] L. Peng, et al. Light: Science & Applications 11 (2022) 73, doi: 10.1038/s41377-022-00758-z
[6] G. Lotze, et al., Journal of Synchrotron Radiation 31 (2024) 42-54, doi: 10.1107/S1600577523010093
[7] J. Keller, et al., Solar RRL 2301018 (2024) 1, doi: 10.1002/solr.202301018
[8] J. Cheng, et al., Matter and Radiation at Extremes 5 (2020) 038401, doi: 10.1063/5.0003288

Speaker: Sebastian Kalbfleisch (MAX IV Laboratory)

136 Current Status of NanoTerasu BL02U: beamline for ultrahigh resolution resonant X-ray inelastic scattering

NanoTerasu BL02U is an ultrahigh energy resolution resonant inelastic soft X-ray scattering (RIXS) beamline. Construction of the beamline started in January 2023 and was completed by September 2023. Construction of the RIXS spectrometer began in October 2023 and was completed by February 2024. Commissioning will start from April 2024 and be open for users from 2025. This beamline is dedicated to a “2D-RIXS spectrometer”, utilizing the energy-dispersive X-ray from the beamline [1]. The designed total energy resolution (combined energy resolution of the beamline and RIXS spectrometer) is sub-10 meV (E/ΔE > 100,000) in the energy range of 500 to 1000 eV. Ongoing development and improvements to the facility are planned to gradually work towards achieving this challenging ultimate goal.
Figure 1 shows a photograph of the constructed beamline and RIXS spectrometer. The beamline is equipped with a vertically dispersing focusing varied-line-spacing plane-grating monochromator with an entrance slit. The sample is placed where an exit slit would typically be installed in a conventional beamline, allowing the vertically dispersed X-rays from the monochromator to directly irradiate the sample. Incident X-ray is horizontally focused by a Wolter mirror just before the sample. Scattered X-ray is vertically imaged by another Wolter mirror to keep the energy information of the incident X-rays. The energy of the scattered X-rays is horizontally resolved, and the energies of both the incident and scattered X-rays are obtained two-dimensionally on the detector. In the presentation, we will provide an overview and report on the current status of BL02U.

[1] J. Miyawaki et al., J. Phys.: Conf. Ser. 2380, 012030 (2022).

Speaker: Jun Miyawaki

figure_s.jpg

137 Toward high-speed and high-accuracy single crystal X-ray diffraction measurements using the integration-type detector CITIUS

Photon-counting two-dimensional (2D) detectors have been widely employed in X-ray diffraction experiments at many synchrotron facilities, contributing to improved signal-to-noise ratio and experimental efficiency. Recently, there has been a growing interest in in-situ and operando measurements, taking advantage of high-intensity synchrotron X-rays to observe transient phenomena. For instance, time-resolved measurements using high frame-rate photon-counting 2D detectors, operating at several kHz, have been explored. However, these detectors suffer from counting loss of strong X-rays, affecting data accuracy. While count-loss corrections are employed, their effectiveness is limited to intensities up to a few Mcps/pixel for commercially available photon-counting 2D detectors, posing challenges in accurately measuring X-rays with peak intensities exceeding this limit. Conversely, the integration-type detector CITIUS, which operates without counting loss and exhibits high saturation count rates, demonstrates linear measurement capabilities up to approximately 900 Mcps/pixel (at 10 keV). Deploying CITIUS detectors for X-ray diffraction measurements is anticipated to yield precise data even for highly intense X-ray diffractions.
At the synchrotron facility SPring-8, an upgrade to the low-emittance ring SPring-8-II is planned, expected to increase X-ray flux by approximately two orders of magnitude for experiments using focused X-rays. This increase in X-ray flux is anticipated to enhance resolution in structural analysis of micro-single crystals, enabling measurement of weaker reflections at higher angles, and thereby improving resolution in structural analysis. In addition, the ability to acquire data in a shorter time is expected to enable high-throughput experimentation, facilitating measurements on a larger number of samples with limited access to beam times. To achieve enhanced resolution and throughput, accurate measurement of diffraction intensities with high peak intensities is imperative. Therefore, we aim to integrate CITIUS into a newly designed micro-single crystal structural analysis system for an undulator beamline. We conducted measurements using a prototype CITIUS detector at SPring-8 BL29XUL, employing a standard ruby sample to reveal various challenges. Figure 1 shows a rocking curve of X-ray diffraction by the ruby ball measured with the CITIUS detector. The presence of two peaks, separated by about 0.05 degrees, is likely due to a partial fracture in the sample. We intend to discuss the results of this proof-of-concept experiment and the identified challenges in the presentation.

Figure 1 X-ray diffraction intensity profile of a ruby ball measured by the CITIUS detector with 30 keV X-rays.

Speaker: Yasuhiko Imai (Japan Synchrotron Radiation Research Institute (JASRI))

SRI2024_Abst2_Fig1_Imai.png

Mikrosymposium 6/2: FELs: New facilities and Opportunitites: MS6/2

138 PAL-XFEL beamline updates and Plans for the second HX beamline

The PAL-XFEL at Pohang Accelerator Laboratory in South Korea provides the best performance and stability for atomic—and femtosecond-level spatiotemporal resolution. Currently, one FEL line each at the hard X-ray and soft X-ray beamlines is in operation, and ten experimental techniques are available for XFEL sciences in physics, materials, chemistry, and biology.
After seven years of user operation, the PAL-XFEL's fundamental research programs have been stabilized and well established. We now need more specialized experimental setups and measurement techniques to facilitate future sciences and industrial applications of XFELs in energy, quantum materials, etc. In addition, the PAL-XFEL reached the maximum available user beamtime after the second half of 2023 with 24-hour-based support. However, the competition for user beamtime remains high due to the limited number of beamlines and insufficient user beamtime at the PAL-XFEL.
To resolve these issues, we have strongly proposed adding the second hard X-ray FEL line (HX2) to the PAL-XFEL to enhance its operational efficiency and scientific capability. Construction of the HX2 line is expected to begin in 2025.
I will share the latest detailed design results for the HX2 and explore ways to enhance the competitiveness of the PAL-XFEL by adding the FEL line.

Speaker: Intae Eom (Pohang Accelerator Laboratory)

139 Generation of ultrashort pulses in the Hard X-Ray range at the European XFEL

Despite significant advancements in generating attosecond pulses in the extreme ultraviolet and soft X-ray regimes, achieving high-power attosecond pulses at Ångstrom wavelengths has remained a considerable challenge. The generation of intense attosecond hard X-ray pulses is pivotal for probing the structural and electronic dynamics of matter with unprecedented precision. Recently, we proposed a self-chirping mode to generate terawatt-attosecond pulses at Ångstrom wavelengths using X-ray free-electron lasers (FEL). This presentation will detail our experiments at the European XFEL, showcasing the successful production of stable high-power single-mode hard X-ray FEL pulses.

Speaker: Jiawei Yan (Eur.XFEL (European XFEL))

140 Status of the FLASH2020+ Project

The free-electron laser FLASH at DESY delivers femtosecond pulses of light from the vacuum ultraviolet to the soft X-ray domain at an average repetition rate of 5kHz. Pulses from the free electron laser can be split and delayed and combined with other sources such as optical lasers and an undulator THz source to perform ultrafast time-resolved experiments. The FLASH facility allows for a large variety of experiments across various science disciplines and offers specially tailored combinations of beamlines and experimental instrumentation. The short-wavelength radiation of FLASH allows to deduce site- and element specific information on electron dynamics.
FLASH is currently undergoing an upgrade within the FLASH2020+ project, which will result in an externally seeded FEL source at high repetition rate. In the current shutdown, a complex electron optics, laser and undulator infrastructure is installed to accomplish this new source via high gain harmonic generation and echo enhanced harmonic generation. This presentation will highlight the technical challenges and opportunities. In addition, the talk will explore methods and science applications of the high coherence, stability, and increased spectral flux of this worldwide unique source.

Speaker: Markus Gühr (DESY)

141 Real-Time Kinetics of Nanogels Driven by XFEL Pulses with MHz Repetition Rate

Stimuli-responsive polymers are an important class of materials with many applications in nanotechnology and drug delivery. The most prominent one is poly-N-isopropylacrylamide (PNIPAm) which has a lower critical solution temperature (LCST) around 32 °C. Below the LCST the polymer is swollen with water, while at higher temperatures the water is expelled from the polymer. The characterization of the kinetics of this configurational change after a temperature jump is still a lively research topic, especially at nm-length scales where it is not possible to rely on conventional microscopic techniques. In this contribution we show results from a real-time experiment of the collapse of a PNIPAm shell on silica nanoparticles with MHz X-ray photon correlation spectroscopy (XPCS) at the European XFEL [1]. Here, the X-ray pulses act both as pump for heating the sample and probe to determine the sample’s structure and dynamics [2], see figure. We characterize the changes of the particles’ diffusion constant as a function of time and consequently local temperature on sub-μs time scales. We developed a phenomenological model to describe the observed data and extract the characteristic times associated to the swelling and collapse processes. In contrast to previous studies tracking the turbidity of PNIPAm dispersions and using laser heating, we find collapse times below μs time scales and two to three orders of magnitude slower swelling times. Finally, we discuss consequences for µs dynamics studies on soft and biological matter at MHz XFEL facilities.

[1] F. Dallari, I. Lokteva, J. Möller, W. Roseker, C. Goy, F. Westermeier, U. Boesenberg, J. Hallmann, A. Rodriguez-Fernandez, M. Scholz, R. Shayduk, A. Madsen, G. Grübel, and F. Lehmkühler. Science Advances 10, eadm7876 (2024).
[2] F. Lehmkühler, F. Dallari et al. PNAS 117, 24110 (2020).

Speaker: Felix Lehmkuehler (DESY)

pnipam_xfel.png

142 Closing the Gap - Integrated Time-Resolved Crystallography at the SwissFEL and Swiss Light Source

The SwissFEL currently provides the hard X-ray endstations Alvra, Bernina, and Cristallina. Especially Alvra is a forerunner in the crystallographic community, having successfully performed many serial femtosecond crystallography experiments, using both, high-viscosity extruders (HVE) and GDVN jets as the sample delivery method [1-3]. With the recently commissioned SwissMX experiment based at Cristallina, there is now also a dedicated setup for fixed-target experiment, both in high-throughput and pump-probe mode, with a mixing setup on the horizon. However, available beamtime at FELs is sparse and entry barrier for new teams is high.

To alleviate these issues and close the probe-time-gap in the millisecond-to-second regime, we build the VESPA endstation at the Swiss Light Source (SLS), dedicated to multi-time-resolved serial millisecond crystallography [4], acoustic levitation goniometry [5], and kilohertz data acquisition serial crystallography [6]. The latter allowed us to push the achievable time resolution at a synchrotron source to microseconds, without the need for choppers. In combination with different pump methods, including dedicated cw and nanosecond Lasers, as well as temperature control, and ligand mixing, this will enable our research community to investigate an even larger array of protein samples.

We will introduce the recently formed PSI focus team for time resolved crystallography, which is dedicated to facilitating easy access to facilities and instruments, as well as providing training and support for research teams interested to get into the field. We will also present an overview of available techniques and expertise, including results from our experimental portfolio, at both SwissFEL and the SLS, and will present an outlook on novel techniques and instruments, especially in light of the upcoming SLS 2.0 upgrade.

---

[1] Skopintsev, P. et. al. (2020) Nature 583, 314
[2] Nass, K. et. al. (2021) IUCrJ 8, 905
[3] Mous, S. et. al. (2022) Science 375, 845
[4] T. Weinert et al. (2019) Science, 365, 61
[5] M. Kepa et. al. (2022) Scientific Reports, 12, 5349
[6] F. Leonarski et al. (2023). IUCrJ 10, 729

Speaker: Florian Dworkowski (Paul Scherrer Institute)

20240409_SRI2024_Figure1.png

143 Crystal Optics Thermal Deformation: Transient Analysis and its Impact to Cavity Based X-ray Free-Electron Laser

Thermal deformation and performance of the crystal optics for high-repetition-rate Free Electron Lasers (FEL) critically depends on the pulse energy and repetition frequency among many other parameters. Time-domain modeling of the thermal deformation of the crystal can help to define acceptable operational parameters across the pulse-energy repetition-rate phase space. In this paper, we present results on pulse-by-pulse full transient thermal deformation of 50-μm thick diamond crystals for a Q-switched Cavity [*Tang et al, 2023] Based X-ray Free Electron Laser (CBXFEL) simulated by using finite element analysis (FEA). The cavity is composed of four diamond crystals. The photon energy was chosen at 9.831 keV to enable high-efficiency Bragg reflection from the diamond (400) reflection at 45.0°. X-ray pulse repetition rate varies from 50 kHz to 1 MHz. Two critical times for the good operation of the crystal are (1) at the time the XFEL makes the 1st-turn so that the crystal sees the recirculated XFEL in the cavity; (2) at the time that the next electron beam arrives for the amplification, so that the crystal outcouples the amplified FEL power. The 1st-turn time (tcavity) is, critical for CBXFEL, related to the total optical path length of the cavity. The electron beam repetition time (tper) is, critical for the X-ray optics in beam transport in the beamline downstream, inversely proportional to the repetition rate (frep): tper = 1/ frep. For the same average power, simulation results show that the crystal thermal deformation seen by the beam decreases with repetition rate at the 1st-turn time of a 300-m long cavity, increases with repetition frequency at the electron beam repetition time. For the wavefront preservation requirement of the crystal, the pulse energy limits at both critical times decreases with repetition rate, especially at the electron beam repetition time. The upper bound of the thermal deformation of the crystal at the electron beam repetition time for any repetition frequency can be estimated from the CW case.

Speaker: Lin Zhang (SLAC National Accelerator Lab)

Abstract_CBXFEL_LinZHANG.pdf

144 Photocatalysis at TiO2 Surface on its Real Time

An acute understanding of photocatalytic reaction dynamics on metal oxides is crucial for the efficient development of technology used for self-cleaning surfaces and for air and water purification. By utilizing femtosecond X-ray laser pulses synchronized with an optical laser (1.6 eV) at FLASH in Hamburg we were able to directly follow the reaction dynamics during photocatalysis at the surface of anatase TiO2 (101) for different prototypical systems; CO/O2/TiO2 and H2O/TiO2. This technique allowed us to monitor the dynamics of reaction product formation with high chemical sensitivity and in real ultrafast time scale.
The femtosecond resolution soft X-ray photoemission spectroscopy results are combined with theoretical calculations to provide crucial insight concerning reaction mechanisms and dynamics. Furthermore, the observation of subtle transient core level shifts provides information on interfacial charge transfer during the initial steps of the reaction immediately following the formation of the photogenerated charge carriers [1,2].

References
[1] Photoinduced Dynamics at the Water/TiO2(101) Interface, Phys. Rev. Lett. 130 (2023) 108001.
[2] Ultrafast Real-Time Dynamics of CO Oxidation over an Oxide Photocatalyst, ACS
catalysis 10 (2020) 13650 – 13658.

Speaker: Heshmat Noei (FS-NL (FS-NL Fachgruppe Spektroskopie))

Thursday 29 August

145 The LCLS-II: High Repetition Rate Free Electron Laser driven by a Superconducting CW Linac

A major upgrade to the Linac Coherent Light Source (LCLS) Free Electron Laser facility has recently been completed. The LCLS-II project delivered a 4 GeV superconducting CW linac, capable of supplying pulses at up to 1 MHz rates in a continuous stream, marking the culmination of a 10-year, $1 billion project.

This beam is used to drive a pair of undulators capable of delivering FEL pulses from 250 eV to 5000 eV, with pulse durations down to the sub-femtosecond level.

A suite of instruments has been built to make use of the new beam, including TMO (time-resolved atomic, molecular and optical science instrument), ChemRIXS (liquid-phase chemical sciences using Resonant Inelastic X-ray Scattering), qRIXS (materials science using time- and momentum (q)- resolved RIXS), and TXI (a dual-beam tender X-ray instrument).

This talk will provide an overview of the current status of the LCLS facility with these new developments, including data from the commissioning and early science programs at the level of 8 to 32 kHz.

The talk will also describe the next phase of upgrades that are currently underway, including the extension to 8 GeV via the LCLS-II-HE Project.

Finally, the talk will offer a perspective on future plans for a next-generation facility known as LCLS-X, and commentary on the anticipated directions for FEL science.

Speaker: Mike Dunne (SLAC National Accelerator Laboratory)

146 Application of Deep Learning Methods for Beam Size Control at the Advanced Light Source

Past research at the Advanced Light Source (ALS) provided a proof-of-principle demonstration that deep learning methods could be effectively employed to compensate for the significant perturbations to the transverse electron beam size induced by user-controlled adjustments of the insertion devices. However, incorporating these methods into the ALS' daily operations has faced notable challenges. The complexity of the system's operational requirements and the significant upkeep demands have restricted their sustained application during user operation. In this talk, we introduce the development of a more robust neural network (NN)-based algorithm that utilizes a novel online fine-tuning approach and its systematic integration into the day-to-day machine operations.

Speaker: Thorsten Hellert (MPY (Beschleunigerphysik))

147 Big data handling

Speaker: Jana Thayer (SLAC National Accelerator Laboratory)

2024 SRI Thayer Big Data Handling.pptx

10:15 Coffee Break

Mikrosymposium 11/3: SR facilites: Updates and New Facilities: MS11/3

148 PETRA IV project

Speaker: Harald Reichert (MPY (Beschleunigerphysik))

149 The New 4th Generation Synchrotron Radiation Source in Korea

The Korea-4GSR (Korea Fourth-Generation Synchrotron Radiation) Project, initiated in July 2021, is a multipurpose synchrotron radiation facility. Led by the Korea Basic Science Institute (KBSI), the project collaborates with the Pohang Accelerator Laboratory (PAL) as a partner institution. The facility will be situated in Ochang, Republic of Korea, an area known for its concentration of industrial companies in fields such as bio-pharmacy, battery cell manufacturing, and semiconductor production. The Korea-4GSR features an 800-meter circumference, operating at 4 GeV energy with a 400 mA current and a 62 pm∙rad emittance. The main ring lattice adopts the hybrid 7 multi-bend achromat type (H7MBA) design, comprising 28 cells. The LINAC and booster/storage ring operate at frequencies of 3000 MHz and 500 MHz, respectively. Out of the 28 straight sections, 24 are reserved for insertion devices, while most of the 28 center bend magnets can accommodate beamlines. In the initial phase, 10 beamlines will be prepared, including 9 insertion device sources and 1 bending beam. Of the long beamlines, one focuses on high-energy microscopy using bending beams, while another enables nano-coherent imaging and nano-scanning microscopy with an in-vacuum undulator. By 2024, the technical designs for the accelerator, beamlines, and conventional facilities will be completed, following acceptance processes by the Project Evaluation Council and the Ministry of Science and ICT. Construction is scheduled to begin in early 2025.

Speaker: Younguk Sohn (Korea Basic Science Institute, KBSI)

150 SPring-8-II Latest Accelerator Design Overview

Takahiro Watanabe
Japan Synchrotron Radiation Research Institute (JASRI)
RIKEN SPring-8 Center (RSC)

SPring-8 major upgrade, SPring-8-II, is undergoing, where we have recently updated our accelerator design aiming at even brighter light source performance. The latest design includes the five-bend lattice at the electron energy of 6 GeV, damping wigglers, and newly develop undulators. The revised five-bend lattice is supposed to produce the bare lattice emittance of 110 pmrad, and the additional damping from damping wigglers and undulators can further reduce the emittance down to 50 to 60 pmrad at minimum. Such an extremely small emittance light source is expected to produce two orders of magnitude brighter x-ray than current SPring-8.
The underlying conditions and strategies for our light source design are (i) to construct a whole new storage ring in the existing accelerator tunnel, (ii) to keep ID beamline axes, (iii) to cover the same spectral range of x-rays as SPring-8, and (iv) to suppress power consumption as low as possible. For (ii), the new lattice is designed while keeping ID positions and angles so that existing ID beamlines will not have to be significantly moved. For (iii), a compact in-vacuum undulator equipped with a magnetic force cancellation, called IVU-II, and a helical-8 undulator have been newly developed covering the same spectral range as SPring-8. For (iv), we plan to install permanent magnet to several kinds of dipole magnets such as longitudinal gradient dipoles. The reduction of the electron energy from 8 to 6 GeV also helps reduce power consumptions. Most of the lattice design and related hardware developments are in the final stage, and we are now preparing for making a prototype cell in fiscal year 2024. Soon after, we expect to start procurements of accelerator components, anticipating the full replacement of accelerators sometime in 2027-2028. The current project plan, the latest accelerator design, expected light source performances, and critical issues will be presented.

Speaker: Takahiro Watanabe (Japan Synchrotron Radiation Research Institute (JASRI) RIKEN SPring-8 Center (RSC))

151 What is Brilliant and BRIGHT at the Australian Synchrotron

The Australian Nuclear Science & Technology Organisation (ANSTO) operates, maintains, and develops a wide range of research infrastructure (worth ~$1 billion) for the benefit of all Australians, including some of the largest research facilities in the country. The Lucas Heights campus in Sydney hosts the Australian Centre for Neutron Scattering, the Centre for Accelerator Science and the National Deuteration Facility. The Clayton campus in Melbourne is home to the Australian Synchrotron, a 3 GeV electron accelerator that is used to generate brilliant beams of infrared and X-ray light for use in a vary array of scientific research – studies in radiotherapy, biomedical imaging and 3-D computed tomography; macromolecular crystallography for the study of the biomolecular basis of disease and the development of new medicines; agricultural, environmental and climate change research; studies in advanced electronics and advanced energy materials; planetary sciences; engineering; advanced manufacturing; and cultural heritage studies. The Australian Synchrotron currently hosts over 1000 experiments per annum across its 14 operational beamlines and is currently in the middle of the ~$100 million BRIGHT Program to design, build and commission the new suite of next-generation beamlines at the facility.

This presentation will showcase recent capability upgrades, as well as a range of impactful research outcomes from the Australian Synchrotron in the fields of health, advanced and energy materials, environmental and climate change research, engineering materials and cultural heritage studies. I will also highlight the new research capabilities from our next-generation BRIGHT Beamlines and look to the future of Synchrotron research capabilities for Australia.

Speaker: Michael James (Australian Nuclear Science and Technology Organisation)

Australian Synchrotron Images.jpg

152 Overview of the Mogno Beamline: Commissioning, Early Scientific Outcomes and Future Installations

Mogno, the micro and nanotomography X-ray beamline at Sirius, was designed to operate in zoom tomography mode, high-throughput, and for in situ experiments. With a nano-focus source, Mogno promises unprecedented resolution for nanostructural analysis at a high-energy beamline, reaching up to 150 nm with energy levels of 22, 39, and 67 keV. Currently partially open to users, the nano-station is attracting researchers from around the world, while the micro-station installation is underway. Mogno's scientific potential spans diverse fields, including groundwater studies, soil characterization, biomaterial research, and fossil examination. As a forthcoming installation, a HPHT (high pressure, high temperature) environmental cell will be available for studying rocks under Brazilian reservoir conditions, a capacity unprecedented in any other beamline and which has the ability to collaborate on very important topics, such as CO2 storage in depleted reservoirs.

Speaker: Nathaly Lopes Archilha (Brazilian Center for Research in Energy and Materials, Brazilian Synchrotron Light Laboratory (LNLS))

153 Synchronized Non-Linear Motion Trajectories of the SCANIA-2D Spectrometer at the Balder Beamline, MAX IV Laboratory

Beamline end-stations often require components to move along non-trivial multi-dimensional trajectories in order to fulfill experimental requirements. These trajectories can often be realised through well synchronized combined motion of multiple axes with single degrees of freedom, such as linear and rotational actuators [1]. A good example of this is the SCANIA-2D (Segmented Crystal Analyzer with Image Acquisition in 2D) x-ray emission spectrometer [2] at the Balder beamline [3], MAX IV synchrotron. Here, five motorized axes are combined to precisely position the crystal assembly and area detector of a Rowland circle geometry x-ray emission spectrometer. Precise positioning is required in order to allow ground-bent (Johansson [4]) crystals to be used, thereby enabling both high efficiency and high resolution operation.

The motion of the five independent motorized axes is combined into an overall crystal assembly and detector trajectory parameterized by just two variables; Bragg angle, θ, and in-Rowland-circle shift, ΔZ. These two parameters are the primary user interface to the spectrometer, from which the constituent motorized axes positions are determined. Motion control is implemented using the IcePAP motion controller [5]. This provides independent closed-loop operation of the constituent axes, as well as synchronized motion along the trajectory defined by the θ and ΔZ. Constituent axis positions are dynamically computed by IcePAP from commanded positions in θ, greatly facilitating user operation. Trajectory configuration, scanning, and data acquisition are provided by the Tango control system orchestrated by Sardana.

---

[1]: P. Sjöblom, H. Enquist, A. Freitas, J. Lidon-Simon, M. Lindberg, and S. Malki, english “Synchronized Nonlinear Motion Trajectories at MAX IV Beamlines” in englishProc. ICALEPCS’23, International Conference on Accelerator and Large Experimental Physics Control Systems No. 19 (JACoW Publishing, Geneva, Switzerland, 2024) pp. 1160–1165
[2]: K. Klementiev, I. Preda, S. Carlson, K. Sigfridsson, and K. Norén, “High performance emission spectrometer at balder/max iv beamline” Journal of Physics: Conference Series 712, 012018 (2016)
[3]: K. Klementiev, K. Noren, S. Carlson, K. G. V. S. Clauss, and I. Persson, “The balder beamline at the max iv laboratory” Journal of Physics: Conference Series 712, 012023 (2016)
[4]: T. Johansson, “Über ein neuartiges, genau fokussierendes röntgenspektrometer,” Zeitschrift für Physik 82, 507–528 (1933)
[5]: N. Janvier, J. M. Clement, P. Fajardo, and G. Cuni, english“IcePAP: An Advanced Motor Controller for Scientific Applications in Large User Facilities,” in englishProc. ICALEPCS’13 (JACoW Publishing, Geneva, Switzerland) pp. 766–769.

Speaker: Marcelo Alcocer (MAX IV)

154 Overview of SSRF Phase-II Beamlines

SSRF Phase-II Beamline Project started from 2016. Its major goal is to establish a systematic, state-of-the-art experiment facility for the third-generation synchrotron radiation to solve problems in cutting-edge science and technology. At present, the construction has been fully completed. All the newly built 18 beamlines with nearly 60 experimental methods have passed acceptance testing by the Chinese Academy of Sciences and been put into operation.

Speaker: Mr Renzhong Tai (Shanghai Synchrotron Radiation Facility,Shanghai Advanced Research Institute, Chinese Academy of Sciences)

Mikrosymposium 3/1: Data, Automation and the Use of AI: MS3/1

155 Machine learning for online optimization and characterization of X-ray FELs: developments and operational experience

Scientific users of X-ray FELs require a wide range of custom photon beam parameters to be delivered within a limited window of time and maintained for the duration of the experiment. In addition, an increasing array of experiments require dynamic control over multiple aspects of the beam during the experiment. This requires precise adjustment of numerous coupled parameters in the accelerator, which is complicated by nonlinear, time-varying behavior and the large number of variables. Machine learning based approaches, such as Bayesian optimization and improvements to it, have enabled highly-efficient online optimization and characterization of particle accelerators and X-ray FELs. Improvements include, for example, addressing common issues such as magnetic hysteresis, accounting for physics-informed coupling between variables, tuning of multiple outputs simultaneously, handling learned output constraints (e.g. keeping a beam on a screen while optimizing), and dealing with nested optimization/measurement tasks. Simultaneously, a key component in bringing these algorithms into regular operation at X-ray FEL facilities is the availability of easy-to-use software that is readily transferable between facilities and tasks. We discuss an overview of these developments and experience at SLAC and collaborating facilities bringing these tools into operation, alongside the impact on operation. We also highlight community software tools that are under development and have been used at multiple light source facilities around the world, including LCLS/LCLS-II, NSLS-II, ESRF, and the European XFEL.

Speaker: Auralee Edelen

156 Robotics developments at SOLEIL

The synchrotron SOLEIL offers to its Users a diverse range of experimental techniques for characterizing various forms of matter in multidisciplinary environments. The upcoming SOLEIL II Project [1] aims to introduce enhanced performance and operational modes, not only in its accelerators but also in the experimental techniques on the beamlines. Automation has been prioritized to meet the evolving requirements and simplify user experiences at the beamlines and accelerator operations. SOLEIL objective is to design systems for flexible instruments control, from manual to fully automated control. This approach includes optimizing experimental procedures, increase beamline efficiency and enhancing sample and data throughput.

Embracing robotics as a strategic topic to improve automation, particularly 6-axis robot arms, SOLEIL is focusing on automating tasks that are repetitive, time-consuming and do not require high expertise levels, such as the constant switching between measurements and sample replacements. Recent applications include the automatic detector positioning for the NANOSCOPIUM beamline, liquid sample injection for the SWING beamline, and mechanical and magnetic adjustments for the insertion device modules. Through these advancements, SOLEIL is driving towards improved automation and operational efficiencies in its cutting-edge research facilities.

1 https://www.synchrotron-soleil.fr/en/future-soleil-soleil-ii-project

Speaker: Laura Munoz-Hernandez (Synchrotron SOLEIL)

6-axisRobotBasedAutomationDevelopmentsSOLEIL.pptx

157 Machine learning for surface scattering: Concepts, challenges, and solutions

Speaker: Frank Schreiber (Universität Tübingen)

158 The Introduction to Mamba Data Worker: The Data Streaming Software Framework for HEPS

The forthcoming deployment of the High Energy Photon Source (HEPS), a fourth-generation light source, is set to produce an unprecedented volume of data, with estimates reaching hundreds of terabytes daily. This development signifies a considerable shift in synchrotron radiation technology and experimental approaches, transitioning from the previously straightforward data transmission pipeline—a single-channel flow from detector to storage—to a complex network involving multiple data generators and applications. To maintain an optimal experimental experience, there is a critical need for effective data management and distribution mechanisms. In response to these challenges, the Mamba Data Worker (MDW) has been developed to fulfill crucial roles such as real-time detector data acquisition, managing interactions with complex dataflows, extracting metadata, reducing data, and facilitating online assembly, writing, and processing. This report details the architecture and developmental roadmap of MDW, outlines the core technologies involved, and showcases its application in settings such as the Beijing Synchrotron Radiation Facility (BSRF) and HEPS, underlining its significance in advancing experimental procedures through enhanced data handling and processing capabilities.

Speaker: Chenglong Zhang

159 ParSeq – a Tool for Creation of Comparative Data Analysis Pipelines

Package ParSeq is a python software library for _Parallel execution of _Sequential data analysis. It implements a general analysis framework that consists of transformation nodes – intermediate stops along the analysis propagation to visualize data, display status and provide user input – and transformations that connect the nodes. It provides an adjustable data model (a collection of data objects that supports grouping, renaming, moving and drag-and-drop actions), tunable data format definitions, plotters for 1D, 2D and 3D data, cross-data analysis routines and flexible widget work space suitable for single- and multi-screen computers. It also defines a structure of Python modules to implement particular analysis pipelines as relatively lightweight Python packages.

ParSeq is intended for synchrotron based techniques, first of all spectroscopy.

In this contribution, I present the basic ideas about the analysis framework, go through the list of centralized facilities (data import/export, plotting, project saving/restoring, undo, dynamically built html help pages etc) and show examples of a few ready pipelines for XAS, XES and XRD.

The main ParSeq package and a few analysis ParSeq pipelines are available on GitHub [github.com/kklmn/ParSeq]. Its online documentation can be viewed on parseq.readthedocs.io .

Fig 1. A screenshot of ParSeq-XAS (an EXAFS analysis pipeline, github.com/kklmn/ParSeq-XAS) as an application example that builds on top of ParSeq framework. The XAS pipeline itself is a relatively lightweight package of less than 2500 lines; it includes all standard EXAFS analysis steps up to EXAFS FT/BFT with atomic shell fitting.

Speaker: Konstantin Klementiev (MAX IV Laboratory)

ParSeq.png

160 InfraRed Adaptive Optics and Machine Learning Optimization for HyperSpectral Imaging

InfraRed Adaptive Optics and Machine Learning Optimization for HyperSpectral Imaging
Vishnu Muruganandan, Samuel Pinilla^, Jaehoon Cha^, Siu-lun Yeung^, Jeyan Thiyagalingam^,
Douglas Winter, Oliver copping, Robert Rambo, and Gianfelice Cinque*⁰

• Diamond Light Source, Harwell Science and innovation Campus, Chilton-Didcot OX11 0DE - U.K.
  ^ Scientific Machine Learning at STFC, Harwell Science and innovation Campus, Chilton-Didcot OX11 0DE - U.K.
  ⁰(honorary) Engineering Science at University of Oxford, Oxford OX1 3PJ - U.K.
  The Multimode InfraRed Imaging And Microspectroscopy (MIRIAM beamline B22) at Diamond Light Source in the UK has been at the forefront of IR micro/nano-spectroscopy research since 15 years. Diamond IR beamline enables a diverse range of applications from life to physical sciences at international level as documented in published literature (B22 publications).
  IR hyperspectral imaging uses a Focal Plane Array (FPA) (pixellated) detector for large field-of-view, Synchrotron Radiation (SR) as a bright IR source, and high magnification optics for enhanced resolution: but the method is hindered by inhomogeneous and anisotropic illumination at the sample plane [1] by SR IR. The resulting IR maps are marred by lesser pixel-level spectra quality, reducing the molecular sensitivity and microimage resolution.
  At MIRIAM, a unique Adaptive Optics (AO) system [2] has been developed for FPA imaging via SR IR. This system is composed by two 97-actuators deformable mirrors, a room-temperature microbolometer diagnostic, and a graphics user interface (GUI). These components work together to provide readout, control, and optimization of the microscope's IR illumination [1].
  Here, we present a pioneering machine learning (ML) development to solve the longstanding challenge of optimal illumination for FPA imaging. By harnessing a Covariance Matrix Adaptation Evolution Bayesian strategy, seamlessly coupled with ad hoc figures-of-merit, this real-time code implementation is integrated within the GUI to learn how to maximize flux and make IR illumination homogeneous. The IR AO system and software optimization algorithm are shown, with first results obtained and maps discussed based on microspectra quality and image fidelity.

Fig. 1. Left: IR AO scheme at MIRIAM. Right: Optimized illumination (bottom) of the initial MIR source (top) using ML method.
[1] Azizian et al. “Beamshaping for infrared hyperspectral imaging: a sequential optimization for infrared source coupling” Optics Letters 47 (2022) doi:10.1364/OL.456049
[2] Azizian et al. “Characterization of double-deformable-mirror adaptive optics for IR beam shaping in hyperspectral imaging” SPIE Photonics Europe proceedings (2020) doi:10.1117/12.2554162

Speaker: Gianfelice Cinque (Diamond Light Source)

SRI2024_SciML_DLS_v3.docx

161 Image Processing for Exascale Synchrotron Science

Today, light source facilities worldwide are evolving into the fourth generation, equipped with diffraction-limited storage rings that have much higher brightness, much lower emittance, and much better coherence. Thanks to such evolution, experiments are transitioning from two-dimensional static characterization into high-throughput, multimodal, ultrafast, and in-situ experiments with dynamic loading, which pushes the temporal and spatial resolution of experimental images to new limits and enables characterization of dynamic structural and functional changes across multiple length scales and modalities.

However, such transition inevitably imposes immense challenges on the software and algorithm end at these facilities. The volume of data, which could reach exascale (billions of gigabytes) each year, is becoming a serious concern. Although welcome progress in image processing techniques, including implementations using machine learning algorithms at light sources facilities has been made, the field remains far from being able to tackle the escalating challenges. In this talk, we first investigate how advanced image processing methods developed in other data-intensive fields such as neuroimaging, cryogenic electron microscopy (cryo-EM), surveillance and autonomous driving, can help address the big data challenge encountered at light source facilities. Then, we present our latest results in developing and applying cutting-edge noise reduction, super-resolution and data reconstruction algorithms on scientific big data. Lastly, we conclude that to address the big data challenge, we are integrating effective algorithms into our self-developed experimental control and data acquisition software framework Mamba to collect, manage, visualize and process big data. We envision Mamba as the operating system of High Energy Photon Source (HEPS). Together, we contend advanced image processing algorithms have all the potential to tackle the exascale big data challenge at next-generation light source facilities.

Speaker: Chun Li (Institute of High Energy Physics)

SRI2024-Abstract.pdf

Mikrosymposium 4/1: New Detector Developments: MS4/1

162 Detector Development at PSI - Past, Present, and Future

The photon science detector group at PSI has more than 20 years of experience in the development of hybrid pixel and microstrip detectors. Initially the focus was on single photon counting detectors and then moved to dynamic gain switching detectors for the upcoming XFELs. Our current developments are driven by Athos the low energy branch of SwissFEL and the upgrade to SLS2 of the SLS. In order to measure low photon energies down to 250eV using our hybrid detectors we work together with FBK on the development of sensors with a thin entrance window and gain in the sensor (iLGADs). These sensors can be used for detectors with single photon counting and charge integrating architectures. Apart detectors for Athos a main goal for the sensor development is also to make single photon counting down to 300-400eV possible. To address the higher expected photon rates at SLS2 we started to develop Matterhorn a new single photon counting detector with the goal to achieve a photon count rate of 20M counts/s per pixel at 80% efficiency which is comparable to today’s charge integrating detectors like Jungfrau.
In my presentation I will give an overview over our current and future developments.

Speaker: Bernd Schmitt (Paul Scherrer Institute)

163 XIDyn: A Charge Cancellation Detector for high Timing and Flux Measurements at 4th Generation Synchrotrons

XIDyn is a hard X-ray detector that will measure fluxes up to 10$^1$$^2$ photons/mm$^2$/s with >100 kHz continuous frame rate and capture bursts of frames at up to 5.7 MHz. The detector will have 144 x 192 pixels on a 110 $\mu$m designed to operate with CdZnTe detector material and operate at energies of 10 - 100 keV.

The XIDyn ASIC is a two-stage charge cancellation and digitisation design. The first “coarse” stage integrates, cancels and counts integer numbers of photons at a time. The second “fine” stage is operated in a pipeline with the coarse stage and resolves single or fractions of a photon using the same charge cancellation method. The "sub-frames" measured on coarse and fine stage counters are merged and stored in the pixel RAM. The pixel RAM can be flexibly programmed so that the sub-frames can be summed, averaged, stored in a sequence, and vetoed before readout. The data is readout as 66b64b aurora encoded packets by serialisers operating at 14.1 Gbps. There are 6 serialisers along one edge of the chip and there is an option to operate all serialiser or one, depending on required frame rate.

The chip has two main modes of operation but retains functionality for other modes. In continuous mode the sub-frames are summed or averaged in the pixel RAM and readout a regular intervals. For example, with a sub-frame rate of 533 kHz to match the orbit of Diamond, and a pixel count of 16 bits, the ASIC could operate with a frame rate of 133.5 kHz. In burst mode, the RAM can be used to capture sequences of sub-frames at rates higher than the output rate of the chip. For example, a sub-frame rate of 5.7 MHz to match the 16-bunch mode of ESRF could be used with an 8 bit value per pixel. The RAM could capture a sequence of 256 sub-frames that are readout at the end of the collection.

In addition to progress in the design of the XIDyn ASIC, results will be presented from a 16x32 pixel MPW ASIC. The electrical performance and measurements made with HF-CdZnTe detectors will be discussed and how these findings may impact the design of the full-scale detector.

Speaker: Matt Wilson (Science & Technology Facilities Council)

SRI2024 - Wilson - XIDyn FINAL.pptx

164 Progress in Developing Novel Germanium Detectors at NSLS-II

At NSLS-II we have a program to develop new detectors based on germanium, to satisfy a demand for detectors with better efficiency at higher x-ray energies. These detectors range from few-element devices with individual readout electronics, to 384-element monolithic strip detectors with multichannel ASIC readout. These have found application on NSLS-II beamlines for a range of applications. We will describe the detectors and their readout systems, and discuss some of the applications.

Speaker: David Siddons (Brookhaven National Laboratory)

165 Advanced X-ray PIxel Detector (AXPiDe v2.0): New Modular Multichannel Detector Based on SDD Available at the XAFS Beamline of Elettra

This contribution will report on a detection system specially designed and developed to fulfil the needs of X-ray Absorption Spectroscopy (XAS) experiments at the XAFS beamline of the ELETTRA synchrotron. It composed of 8 monolithic multipixel arrays of Silicon Drift Detectors (SDDs), each comprising 8 cells (3x3 mm2) fabricated on 450-μm-thick n-type high-purity silicon wafers with a Tungsten collimation system. This results in 64 independent cells for a total collimated area of 500 mm2. All arrays are connected to separate back-end electronics and calibrated, aligned and summed through the acquisition software. Moreover, the system includes custom-made ultra-low-noise front-end electronics, a dedicated acquisition system, digital filtering, temperature control and stabilization. The sensor is optimized to operate in the energy range 3-30 keV. A dedicated acquisition software, Fluorescence Instrumentation Control Universal Software (FICUS), developed using NI LabVIEW allows the instrumental performances to be controlled, fine-tuned and monitored, and is fully integrated with the control system of the beamline for the data acquisition. Accurate characterization performed at room temperature at the XAFS beamline in Elettra demonstrated very interesting results in terms of energy resolution with a FWHM below 170 eV at the K line of Mn 5.9 keV for the sum of all cells, high count rate and excellent peak-to-background ratio. All these specifications make it possible to collect high-data-quality XAS spectra on diluted elements embedded in heavy matrices, to improve the throughput of the beamline or to follow slow kinetic.

Speaker: Giovanni Agostini (Elettra synchrotron)

SRI_2024_Abstract_v3.docx

166 HEPS-BPIX4 : Process in 6M Hybrid Pixel Detector Design and Engineering Prototype for HEPS

Abstract: HEPS-BPIX4 is a new engineering generation hybrid pixel detector prototype with 6M pixels with 140um×140um following the previous one with a pixel size of 150um×150um and frame rate up to 1.2kHz at 20-bit dynamic range. The 6M pixel detector is design for the Biological macromolecule experiment station of HEPS(BA beamline), which will be operational by 2025. The BPIX chip, fabricated in a radiation tolerant design with a standard 0.13um CMOS process, was used to construct multichip modules with a active size of 82.2X36.8mm2 comprising 256X576pixels.
The BPIX4 readout chip was improved in terms of pixel size, electronic noise, number of threshold compared with the previous ones. The comparator threshold of each pixel is adjusted with a global threshold voltage (VCMP) and can be individually trimmed with a 5 bit digital-to-analog converter (5 bit DAC). There are two comparators and two counters in each pixel and a digital pulse from the comparator increments the each 16bit counter, leading to completely digital storage of the number of detected X-rays in each pixel.
The silicon sensors used for the modules were designed at IHEP and fabricated by inhouse fab. Each pixel consists of a pn-junction realized by a highly doped p-electrode implanted into a high-resistivity n-bulk. The sensors with a thickness of 450um are fully depleted at about 60 V and normally biased with 100 V.
A detector module consists of a single, fully depleted monolithic silicon sensor bump-bonded to an array of 2X6 ROCs. A model of the hybrid architecture is shown in Fig.1. Each sensor pixel is electrically connected to its corresponding ROC pixel with an Sn-Cu bump ball of 25to 35 m diameter. Wire-bonds are used to connect the pads on the side of the ROC to further readout electronics.
One module together with a detector control board (DCB), a data acquisition computer and a power supply forms a standalone detector system with 1.2KHz readout frame rate. A multi-module setup of 6M engineering prototype can be realized by mounting modules on a high-precision mechanical frame. The 6 M is an array of 5×8 modules comprising 5898240 pixels on an active area of 411 mm 294 mm achieving 200 Hz maximum frame rate. It is used at the macromolecular crystallography beamline BA at the HEPS.
All presented calibrations and characterizations were carried out at the BSRF using monochromatic X-rays since better results were achieved with X-rays than with the internal calibration signal of the readout chip. Either the direct synchrotron beam in combination with absorbing filters or an elastic scatter for homogeneous detector illumination were used.

Speaker: Zhenjie Li (Institute of High Energy Physics)

X-ray fish.png

微信图片_20230406154300.jpg

167 Development of a New Generation Multi-Element Monolithic HPGe for XAFS Applications

X-ray Absorption Fine Structure spectroscopy (XAFS) is crucial to investigate the electronic and atomic structure of different kinds of samples [1]. The efficacy of this technique, widely deployed at synchrotron facilities, is constrained by the performance limitations of the current generation of Ge detectors. To perform XAFS measurements, energy-resolving detectors capable of handling high count rates are essential [2]. While efforts have been focused on developing arrays of Silicon Drift Detectors (SDDs), less attention has been given to enhancing the performance of High Purity Germanium (HPGe) detectors for synchrotron applications. HPGe detectors offer better detection efficiency at high energies compared to SDDs.
To address this, a detector consortium under the European project LEAPS-INNOV [3] launched an ambitious R&D program aimed at developing a new generation of multi-element monolithic HPGe detectors specifically tailored for X-ray detection [4]. Two detector prototypes are currently under development and are anticipated to undergo characterization in early summer 2024. Simulations of the detector prototypes have been conducted to optimize the detector performance. Each prototype is equipped with a 10-element monolithic HPGe sensor, one with a 5 mm2 area pixels and another with 20 mm2 area pixels. Additionally, a novel electronic chain has been engineered, allowing crosstalk and charge-sharing correction, and enabling the processing of higher count rates ranging from 20 kcps/mm2 up to 250 kcps/mm2, while preserving reasonable energy resolution and minimizing dead time within the required energy range.
This work presents a comprehensive overview of the detector prototypes, encompassing mechanical design details, HPGe sensor specifications, electronic configurations, and their individual performance. Furthermore, results from simulations aimed at optimizing the detector's functionality are presented and analysed. Currently, the prototypes are undergoing assembly, with forthcoming laboratory and beamline tests planned before Summer 2024 to evaluate their performance. First results of the detector characterization will also be reported.
[1] G. Bunker, ”Introduction to XAFS: A Practical Guide to X-Ray Absorption Fine Structure Spectroscopy”. Cambridge, U.K., Cambridge Univ. Press, 2010.
[2] N. Tartoni, et al., ”Hexagonal Pad Multichannel Ge X-Ray Spectroscopy Detector Demonstrator: Comprehensive Characterization,” in IEEE Transactions on Nuclear Science, vol. 67, no. 8, pp. 1952-1961, Aug. 2020.
[3] LEAPS pilot to foster open innovation for accelerator-based light sources in Europe, European Union’s Horizon 2020, Grant Agreement No. 101004728.
[4] F. Orsini, et al., “XAFS-DET: a new high throughout X-ray spectroscopy detector system developed for synchrotron applications”, Nucl. Instrum. Meth. A, Volume 1045, 2023, 167600, https://doi.org/10.1016/j.nima.2022.167600.

Speaker: Eva Gimenez (DLS)

168 TEMPUS, a Timepix4-Based Detector for Photon Science

DESY in Hamburg, operates one of the brightest storage ring (SR) light sources in the world: PETRA III. The upcoming upgrade of the facility to a 4th generation SR, the PETRA IV project, will increase the brilliance by orders of magnitude and put pressure on existing instrumentation, including detectors. In order to take full advantage of the elevated flux, DESY has engaged in the development of fast and efficient x-ray detectors. A new readout chip has been recently produced by the Medipix4 collaboration: Timepix4, which combines photon-counting full-frame readout mode and event-driven time-stamping mode, with greatly enhanced performance over both Medipix3 and Timepix3. The single chip TEMPUS (Timepix4-based Edgeless Multi-Purpose Sensor) detector is being developed as a replacement to LAMBDA.
When running at full speed, the 16 gigabit wireline transmitter (GWT) responsible for sending the data out of the chip, will reach a total bandwidth of over 80 Gbps. Dealing with this large amount of data is one of the main challenges ahead. The chip was also designed to take full advantage of the through silicon via (TSV) technology and therefore we will be able to fully remove the wirebond connections on the sides, decreasing the dead areas when placing several chips together, which is also planned for future iterations of the prototype.
With 512 x 448 pixels, 55 µm pixel size, the chip offers a larger pixel area than its predecessors, 10 times higher count rate in the the photon-counting mode and up to 40 kHz frame rate, as well as 200ps time resolution in the event-driven mode. All the tests discussed here were done using this latter mode. In this mode, a relatively high time resolution can be achieved. Also, under moderate incoming flux, a large reduction in the data volume is possible. Two experiments took place at PETRA III and ESRF. We were able to capture the electron bunch structure of both facilities. Also, when using a 300 µm p-on-n Si sensor fully biased, time resolutions as low as few ns were achieved. The combination of high time resolution and fast readout bandwidth will be crucial for many applications at 4th generation SR and also FELs.

Speaker: Jonathan Correa (FS-DS (Detektorsysteme))

SRI_2024.pdf

Mikrosymposium 6/3: FELs: New facilities and Opportunitites: MS6/3

169 Towards pulses with Orbital Angular Momentum at the European XFEL

High-power attosecond X-ray pulses carrying orbital angular momentum (OAM) are promising tools for various scientific applications, including imaging and spectroscopy. Self-seeded free-electron lasers (FELs) with OAM (SSOAM) offer an attractive approach for producing these pulses. In this work, we discuss several aspects concerning the generation of XFEL pulses carrying OAM with a SSOAM setup, with in mind in particular the European XFEL. We examine the formation of helical microbunching and its interaction with the radiator, whether helical or planar, in determining the topological charge of the resultant radiation pulse. Then, assuming that the SSOAM seed signal is short (different methods, e.g. ESASE can be used for the goal of creating such a short seed), we consider the separate evolution of different FEL modes along the setup, according to semi-analytical theory. We discuss how the real and imaginary parts of the eigenvalues for different eigenmodes may be used to tune the relative final position and magnitude of different OAM modes at the exit of the setup.

Speaker: Gianluca Aldo Geloni (Eur.XFEL (European XFEL))

170 Recent results in ultrafast science at the LDM beamline

The FERMI Free Electron Laser in Trieste (Italy) has been designed and built as a seeded source, for precise control of the properties of its light pulses. Its excellent longitudinal coherence is inherited from the seed laser, and is its uppermost distinctive feature. In the realm of atomic, molecular and optical science, the use of longitudinal coherence of laboratory lasers as a time reference for precise measurements, as a control parameter for the synthesis of arbitrary waveforms, and for steering the outcome of a photophysical process, has a long history of achievements. One wishes to extend the same concepts to shorter wavelengths, because the latter provide higher spatial and temporal resolution, as well as chemical selectivity.

The Low Density Matter (LDM) beamline at FERMI has been serving the atomic, molecular and cluster science community since its opening at the end of 2012. Through the use of interchangeable supersonic jet sources, it offers the possibility of studying atoms and molecules (including aligned ones), as well as more exotic systems such as superfluid helium droplets or metallic nanoparticles. Ion and electron spectroscopies (time-of-flight; velocity map imaging) and coherent diffraction imaging are available in one of the few different standard configurations of the endstation. Users’ equipment can be accommodated as well, and several experiments have also been performed in non-standard configurations. A synchronized infrared laser (with second-, third-, and fourth-harmonic generation capability) is available for optical+FEL experiments. The LDM beamline has worked in close synergy with the Machine Physics team to help characterize FERMI, and develop new modes of operation.

In this talk I will present recent results related to recent technical developments, specifically on molecular dynamics explored with time-resolved core-level photoelectron spectroscopy, nonlinear applications of phase-locked harmonics, and diagnostics of FEL operation, as well as future opportunities.

The results originate from the joint effort of many international laboratories and of a large number of researchers, whose work is gratefully acknowledged.

Speaker: Carlo Callegari (Elettra - Sincrotrone Trieste)

171 Development of superradiant THz sources at NSRRC

Linac-based coherent THz radiation sources are being developed with the NSRRC high brightness photoinjector which has been installed in the Accelerator Test Area (ATA). The injector is equipped with a laser-driven photocathode rf gun and a 5.2-m long S-band traveling-wave linac for beam acceleration. A sub-picosecond electron bunch with 27-MeV beam energy has been produced from this injector by the so-called velocity bunching technique. Intense narrow-band superradiant THz radiation with tunable central frequency from 0.6 to 1.5 THz can be generated by injecting such ultrashort beam into a U100 planar undulator. The other broadband THz coherent transition radiation (CTR) generated by passing this beam through a metallic foil is used for measuring the bunch length by autocorrelation technique. Currently the electron bunch length is measured to be 240 fs with the field gradient 13.8 MV/m. Improvement of better beam quality of this photo-injector and construction of the THz user facility are under consideration.

Speaker: Ming-Chang Chou (National Synchrotron Radiation Research Center)

172 Enhancing Elastic X-ray Scattering via Transient Resonances

X-ray free electron lasers (XFELs) offer the capability to produce ultra-intense (>10e12 photons) and ultra-short (few and sub-femtoseconds) x-ray pulses. The exceptional intensity of these pulses enables the massive ionization of core electronic states, resulting in the creation of transient resonances. Despite the inherent challenge posed by the ultra-fast decay time of these transient states, typically governed by the Auger-Meitner process and lasting 1-2 fs, the brief duration of XFEL pulses allows for the exploration of transient states before their decay. This leads to collective emission phenomena, such as x-ray lasing and x-ray seeded emission spectroscopy. Our investigation focuses on using transient resonances to enhance the elastic scattering factor of individual atoms. Analogous to resonant scattering, where an x-ray pulse with a wavelength matching a core-to-valence transition experiences an increased scattering factor, we utilize a core-to-core transient resonance in this context.

During an experiment at the SCS beamline of EuXFEL, we studied the scattering properties of Cu atoms irradiated by intense XFEL pulses. X-ray pulses are tuned to the Cu-Lα transition (929.7 eV) and focused down to 20 µm onto a 150 nm thick multilayer ([B4C/Cu/SiC]n) target. Photoionization followed by rapid Auger decay produces hot unbound electrons in the sample. A subsequent cascade of electron-electron collisions generates highly charged ions with severe depletion of the Cu 3d shell. In a previous transient x-ray absorption experiment of Cu [1], the authors identified an absorption peak below the natural Cu-L3 edge (932.7 eV). This peak results from the resonant 2p-3d excitation (Cu-Lα transition) of the created 3d vacancies. Correspondingly to resonant absorption, the transient 2p-3d resonances reflect in additional resonant elastic x-ray scattering channels. This results in enhanced scattering strength of individual atoms. We demonstrated that the enhancement strongly depends on the intensity of the incoming pulse and can grow to one order of magnitude. Our findings encourage the application of the effect in innovative crystallographic methods where 3d metals may act as heavy scatterers in analogy with single-wavelength anomalous dispersion.

In this contribution, I will introduce the fundamental concept behind the enhanced resonant elastic scattering (ERES) process. Furthermore, I will present the results of the experiment conducted at the SCS beamline of the European XFEL, where we pursued ERES in a copper-based target.

[1] Mercadier L. et al., Preprint, 2023, 10.21203/rs.3.rs-2396961/v1.

Speaker: Daniele Ronchetti (FS-TUX (Theoretical ultrafast X-ray science))

173 SABINA and SISSI 2.0: Two Underway Projects for Innovative THz/IR Sources Based on Particle Accelerators

Terahertz/Infrared (THz/IR) radiation and technologies have witnessed incredible development in recent decades owing to their application in a great variety of fields, ranging from scientific research in physics, medicine and biology to research topics closer to our daily lives, such as communications, security or environmental science. In order to push the boundaries of research in all these fields, it is necessary to develop innovative technologies that enable the generation, manipulation and detection of THz/IR radiation, a task that is part of an existing framework aimed at filling the so called 'THz Gap'. Among the sources that embrace this spirit of innovation, those based on particle acceleration could provide high-power THz and IR radiation with tunable properties in terms of time duration, frequency spectrum and polarization.
Two Italian projects, SABINA and SISSI 2.0, are currently underway for the realization or the upgrade of innovative THz/IR sources based on particle acceleration. These projects include two of the most important research facilities in Italy, i.e. the SPARC_LAB linear accelerator at the National Laboratories of Frascati (INFN-LNF) and the third-generation synchrotron, Elettra, in Trieste.
The SABINA project aims to implement some major upgrades to the SPARC_LAB structure, including the practical goal of realizing a FEL, operating as an external user facility. A sequence of three APPLE-X undulators downstream a LINAC are used to produce pulsed monochromatic radiation in the spectral range 3-30 THz, with energy up to ∼100 μm/pulse, with time durations in the sub-ps/ps range and with tunable polarization (circular, elliptical and linear). The radiation is transported through an optical beamline to an external 'open-to-user' laboratory, equipped with appropriate set-ups to perform scientific experiments concerning non-linear and time-resolved optical spectroscopy.
In the same spirit of innovation, the SISSI 2.0 project is part of a more general upgrade, ELETTRA 2.0, that is intended to create an 'ultimate' light source, characterised by a substantial increase in brilliance and coherence, through the implementation of new magnetic optics designed to preserve the basic features of the accelerator. All the beamlines are involved in the upgrade, including SISSI (Synchrotron Infrared Source for Spectroscopy and Imaging), which is the line dedicated to the collection of THz/IR radiation emitted by magnetic dipoles. The SISSI 2.0 Project aims to characterize the radiation produced by this beamline focusing on the interference effects and on the emergence of new edge radiation contributions caused by the complex magnetic structure of the new multi-bend achromats.

Speaker: Lorenzo Mosesso (Sapienza, University of Rome)

Mosesso Lorenzo Abstract.docx

174 Thermal Stability of Multilayers for Use with High X-ray Intensities

Extreme focusing of XFEL beams is required to achieve power densities needed for applications like single-particle imaging or studies of nonlinear physics. However, focusing optics needs to have high radiation hardness and minimal absorption. We are developing multilayer Laue lenses (MLLs), diffraction-based X-ray optics with which we can focus X-rays to nanometer spot sizes. However, these multilayer-based lenses have so far included high atomic number materials such as tungsten or tungsten carbide. Numerical simulations predict that for high incident fluxes and pulse repetition rates these MLLs suffer from high heat load. Using materials with low atomic numbers would significantly decrease this heat load. In this presentation we will present our numerical and experimental study on screening various multilayer material pairs that could be used in MLLs for focusing XFEL beams. The most promising multilayer pair was then studied in more detail. This included annealing studies of different periods and material ratios using different heating rates. The annealing experiments indicate that MLLs made of lower atomic number multilayers are expected to withstand XFEL conditions with no deteriorations for an XFEL beam with an energy of 1 mJ per pulse, photon energy of 17.5 keV, and a repetition rate of 10 kHz.

Speaker: Margarita Zakharova (FS-ML (Multilayer))

175 High Photon Energy X-ray Absorption and Emission Spectrometers at the FXE instrument of European XFEL

X-ray probes, e.g., X-ray absorption and X-ray emission spectroscopies (XAS and XES, respectively) have the advantage of being sensitive to the electronic configurations and local structures around the absorbing element. They have routinely been employed to study photoexcited states of materials at synchrotron radiation and X-ray Free Electron Laser (XFEL) large-scale facilities. Time resolved (tr) X-ray spectroscopies have rarely been employed in very hard X-ray regimes, mainly due to the lack of X-ray sources. Femtosecond X-ray Experiments (FXE) has unique capability of delivering high photon energies, allowing X-ray spectroscopies to be performed above 18 keV 1, which covers the K-edges of 4d elements and L-edges of 5f elements. However, there are inherent challenges for high photon energy spectroscopic pump-probe techniques. To our knowledge, currently, there is no fs time resolution X-ray spectroscopic studies at such high energy. Very recently, FXE succeeded in collecting XAS spectra at niobium K edge (~19 keV). XAS at high X-ray energies is fundamentally limited by the large core-hole lifetime (CHL) broadening [2], which obscures the interpretation of near-edge features and comparison with theory. One way to overcome CHL broadening is to use high resolution detection (HERFD) mode, wherein an efficient X-ray spectrometer is necessary. Standard XES spectrometers operating in Bragg reflective geometry quickly loose efficiency at energies > 15 keV, thus new approaches are needed.
In this contribution, we will present our recent XES and XAS developments at the FXE instrument on high photon energies (>18 keV). A transmission-type spectrometer equipped with Laue analyzers made of silicon and quartz was recently commissioned at FXE, providing an energy resolution of about 2.5 eV (ΔE/E-1.2×10-4) at about 16-19 keV with improved photon collection efficiency [3,4]. Considering the natural linewidths of emission lines at 16-19 keV are usually 5-7 eV, our spectrometer will be able to well resolve the emission spectrum of 4d and 5f elements. Benefiting from the recent developments at FXE, we have recently performed tr-XAS measurements with ~100 fs time resolution on a photocatalyst nanoparticle Nb2O5 in solution. The first X-ray spectroscopic results provide a route for future tr-studies at high photon energies using high energy resolution. For example, HERFD-XAS measurements using our new Laue analyzers can enhance the XAS resolution to overcome the limitation imposed by CHL broadening, which is important for deconvoluting the states originating the pre-edge features and significantly improving the comparison with calculated spectra [2].

[[1]] D. Khakhulin et al. Ultrafast X-ray photochemistry at European XFEL: capabilities of the femtosecond X-ray experiments (FXE) instrument. Appl. Sci. 10, 995 (2020).
[2] F. Lima et al. High-resolution molybdenum K-edge X-ray absorption spectroscopy analyzed with time-dependent density functional theory. Phys. Chem. Chem. Phys. 15, 20911 (2013)
[3] P. Jagodzinski et al. A DuMond-type crystal spectrometer for synchrotron-based X-ray emission studies in the energy range of 15–26 keV. Rev Sci Instrum 90, 063106 (2019).
[4] X. Huang, et al., in preparation.

Speaker: Xinchao Huang (Eur.XFEL (European XFEL))

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Mikrosymposium 7/3: Imaging and Cohrerence Applications: MS7/3

176 Talbot imaging of laser shock driven lattice dynamics

Speaker: Bob Nagler (SLAC)

177 Hard x-ray imaging of shockwaves generated by a short-pulse high-intensity laser

Dynamic shock compression serves as a crucial tool for creating warm and hot dense matter under extreme conditions that exist throughout the universe such as the interior of planets, supernovae, and astrophysical jets. Converging shocks are particularly valuable as they deliver energy to a small volume, resulting in the compression of material to exceedingly high densities and pressures. The generation of converging shocks requires precise design and facilities enabling laser irradiation with multiple beams such as OMEGA, NIF, or LMJ, with 10 kJ to MJ energies.
We report the discovery of a robust new technique to compress material to extreme pressures and densities, comparable to condition achievable at major international 10kJ- to MJ-class laser implosion facilities, using a table-top Joule-class short pulse laser and diagnosed with a hard X-ray Free Electron Laser. Thanks to the highly spatial coherence, extreme short pulse length and high brilliance of the XFEL beam, it is now possible to image transient effects with sub-micrometer spatial resolution and sub-picosecond temporal resolution. We will show how compression of a copper wire up to hundreds of Mbar can be potentially achieved with a single beam, of 30fs and just 3 J of energy. We also show compression results of other materials of planetary and stellar astrophysics interest such as carbon and iron as well as CH mixtures.

Speaker: Alejandro Laso Garcia (Helmholtz-Zentrum Dresden - Rossendorf)

178 Operando Metal 3D Printing at X-ray Free Electron Lasers

While laser powder-bed fusion (LPBF) enables new design paradigms for metals manufacturing, uncertainties persist in connecting the process optimization to the apparently stochastic variability of the resulting properties. Operando X-ray radiography has revealed complex competition between multi-physics phenomena during the melt and solidification processes, resulting in variable turbulence during competition between keyholing, Marangoni flows, heat transfer, etc. Correlating these melt-pool phenomena with the fracture and phase segregation that can occur upon solidification is often not possible with the μm-resolution limits of radiographic imaging with >100-picosecond duration imaging pulses. We present the first LPBF experiments that use X-ray free electron lasers (XFELs) whose femtosecond-duration pulses and 1012 photons per pulse enable opportunities for new types of operando microscopy to reveal these critical phenomena during LPBF. The insights from our novel microscopes hold profound opportunities to access the next generations of length and timescales for LPBF physics.

Speaker: Leora Dresselhaus-Marais (Stanford University)

179 Advances in Quantum X-ray Imaging

Abstract
In this study, we explore the generation of entangled photon pairs through the process of nonlinear Bragg diffraction in the X-ray spectrum to perform X-ray spontaneous parametric down conversion (SPDC). SPDC is traditionally achieved using birefringent nonlinear materials in the visible and near-infrared regime[1]. By orienting the medium (single crystal diamond) and the X-ray pump to initiate Bragg diffraction and then slightly deviating from the ideal Bragg angle, we satisify phase matching condition as per the law of nonlinear diffraction[2].

Our breakthrough at the NSLS-II’s CHX (11-ID) beamline involves the successful detection of X-ray SPDC photon pairs at an unprecedented rate of approximately 6,100 pairs per hour, significantly surpassing the previously known highest rate of 317 pairs per hour[3]. Not only do we showcase the strong energy anti-correlation of these pairs[4], but we also introduce the first images of their spatial structure captured using a pixelated area detector. Our research includes quantum correlation images of both binary and biological subjects using this X-ray source, a discussion on the effect of crystal quality on the photon pairs, and an exploration of potential applications, backed by simulations.

This advancement in the production and identification of correlated X-ray states heralds a range of promising applications. The relatively high efficiency of this source paves the way for quantum X-rays applications using quantum/ghost imaging techniques. These include reducing radiation dosage while retaining image quality, achieving lensless magnification and super-resolution imaging, and delving into fundamental quantum physics within a previously lesser-explored part of the electromagnetic spectrum.
This project is supported through United States DOE-BER Bioimaging Science Program KP1607020, within Biological Systems Science Division BSSD’s Biomolecular Characterization and Imaging Science portfolio.

Figure Captions
1. Experimental setup.
2. SPDC X-ray detection rate progress over time.
3. SPDC X-ray selection observables and spatial properties.
4. Experimental X-ray SPDC ring, imaging mask, and energy non-degeneracy mappings.
5. Classical and quantum correlations images of E. cardamomum seed.

References
1. Christ, A., et al., “Parametric down-conversion. In: Experimental Methods in the Physical Sciences.” vol. 45, pp. 351–410. Elsevier, Amsterdam (2013).
2. P. Eisenberger, S. L. McCall, “X-ray parametric conversion.” Physical Review Letters 26, 684 (1971).
3. D. Borodin, A. Schori, F. Zontone, S. Shwartz, “X-ray photon pairs with highly suppressed background.” Physical Review A 94, 013843 (2016).
4. Goodrich, J. C., et al., "Imaging of X-ray Pairs in a Spontaneous Parametric Down-Conversion Process." arXiv preprint arXiv:2310.13078 (2023).

Speaker: Justin Goodrich (National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA.)

Advances in Quantum X-ray Imaging.docx

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180 Coupled Holo-Tomography: Improved 3D Object Reconstruction

Near-field inline holography enables imaging of microscopic objects, including biological specimens, offering rapid data acquisition based on full-field imaging. Object-induced phase shifts on a coherent illumination are encoded in interference patterns at the detector. Its intensity distribution is recorded in a hologram. However, the reconstruction of the phase shift from the (single-projection) hologram forms an ill-posed inverse problem and requires iterative phase retrieval. In holo-tomography, holograms are acquired at multiple angles under a 180° rotation to access the internal structure.

In conventional holo-tomography reconstruction, holograms are intensity-corrected for the illumination through flat-field correction. Phase shifts for all angles are calculated using an iterative phase retrieval algorithm, and cross-sections of the reconstructed object are determined via inverse Radon-transform. To improve the reconstruction quality, we propose the following coupled holo-tomography approach. Complex phase shifts are retrieved by simultaneously correcting for the complex illumination function, effectively removing any distortions stemming from the illumination. After a few iterations of phase retrieval, a preliminary tomogram is determined, supplemented with a loose support constraint to suppress reconstruction artifacts. From this first tomogram, updated projections are calculated and serve as an updated guess for further phase retrieval. By alternating between phase retrieval and the tomographic reconstruction, we obtain an improved 3D reconstruction in comparison to applying only one tomographic step consecutive to phase retrieval, and an artifact-free object is enforced through tomographic consistency through the data set.

This approach improves the holo-tomographic reconstruction by correcting for a complex illumination, reducing reconstruction artifacts and improving phase retrieval by updating its estimations from tomographic reconstruction projections. Simulation results, based on a 3D object consisting of strong induced phase-shifts and sharp edges, emphasise the efficiency of coupled holo-tomography compared to the standard approach. Our coupled holo-tomography approach promises significant improvements in the 3D object reconstruction for X-ray near-field holo-tomography experiments.

Speaker: Thea Engler (Center for X-ray and Nano Science CXNS, Deutsches Elektronen-Synchrotron DESY; Department Physik, Universität Hamburg UHH)

181 Dose-Efficient Propagation-Based X-ray Phase Contrast Imaging at High and Low Resolution by Bragg Crystal Optics

X-ray phase contrast imaging techniques can visualize weakly attenuating samples such as soft materials or biological tissues by exploiting the phase shift that the sample imprints on the incident wavefield. Propagation-based phase contrast imaging (PB-PCI) exploits the self-interference of the diffracted wavefield behind the sample, which gradually evolves into intensity contrast as the propagation distance between sample and detector increases. In principle, PB-PCI can be employed for imaging at both high, micrometer resolution as well as moderate resolutions of several tens of micrometers. However, both resolution regimes face severe constraints. On the one hand, conventional scintillator-based detectors with micrometer resolution suffer from decreasing efficiency with increasing resolution. On the other hand, imaging large samples at moderate resolution requires tens to hundreds of meters propagation distance to generate sufficient image contrast. Recently, a new beamline has been built at the ESRF to facilitate PB-PCI at remarkably long propagation distances of up to 36 m, tailored to the X-ray source size [1].

We overcome both above-mentioned limitations by employing Bragg crystal optics. For high resolution, a Bragg magnifier allows directly magnifying the X-ray wavefield and using a highly-efficient single-photon-counting detector (SPCD) while maintaining micrometer resolution. The developed system operates close to the theoretical limit of dose efficiency for PB-PCI [2]. We prove the superior imaging performance compared to conventional detector systems and show a substantial increase in dose efficiency for high spatial frequencies that comprise the relevant high-resolution components of the image. Further, we demonstrate the technique’s potential by a pilot in vivo study of submillimeter-sized parasitoid wasps (Fig. 1).

For imaging large, centimeter-sized samples at moderate resolution (several tens of micrometers), we present a new technique that allows achieving strong image contrast within a meter-scale setup, thereby eliminating the need for very long propagation distances [3]. Simultaneously, the technique reduces image blur caused by the finite X-ray source size. The strong increase in image contrast is demonstrated in a proof-of-concept experiment realized by a Bragg demagnifier (Fig. 2). This approach paves the way for low-dose studies of large radiation-sensitive samples, with potential applications ranging from biomedical soft tissue and small animal in vivo imaging up to medical diagnostics, e.g., the early detection of breast cancer.

References:
[1] T. Lang et al., "Multiscale Phase-Contrast Tomography at BM18", e-Journal of Nondestructive Testing 28 (2023)
[2] R. Spiecker et al., "Dose-efficient in vivo X-ray phase contrast imaging at micrometer resolution by Bragg magnifiers", Optica 10.1364/OPTICA.500978 (2023)
[3] R. Spiecker et al., "The Bragg demagnifier: X-ray imaging with kilometer propagation distance within a meter", arXiv:2310.16771 (2023)

Figure captions:
Figure 1: Dose-efficient in vivo imaging at micrometer resolution.
Figure 2: PB-PCI of a large sample at 1 m physical propagation distance for conventional PB-PCI (left) and with the proposed method (right).

Speaker: Tilo Baumbach (Karlsruhe Institute of Technology)

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182 Highly Sensitive Full-Field X-ray Absorption Spectro-Imaging via Physics Informed Machine Learning

Improving the spatial and spectral resolution of 2D/3D imaging of the X-ray near-edge absorption structure (XANES) has been a decade-long pursuit to probe local chemical reactions at the nanoscale. However, the poor signal-to-noise ratio in the measured images poses significant challenges in quantitative analysis, especially when the element of interest is at a low concentration. Recently, we have developed a post-imaging processing method using deep neural network to reliably improve the signal-to-noise ratio in the 2D-XANES images, collected at the FXI beamline at NSLS-II at Brookhaven National Laboratory (see Fig. 1). It is worth noting that the proposed neural network could be trained to adapt to new datasets by incorporating the physical features inherent in the latent space of the XANES images and self-supervised to detect new features in the images and achieve self-consistency. With examples, we will demonstrate the robustness of the model in analyzing the valance states of Ni, Co, Mn in the 2D XANES images with low signals. We will also discuss the generality of the model when applied to different types of elements which have not been seen during the network training. The neural network has been incorporated into the in-house developed PyXAS package and it is freely distributed for general usage.

Speaker: Mingyuan Ge (Brookhaven National Lab)

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13:00 Lunch Break

183 Lunch seminar: Lightsources.org - Science Communication lunchtime session

This interactive workshop will be run by science communication professionals from light sources in the US and Europe. Learn from their many years of experience, develop your skills and pick up some Top Tips to enhance your science communication activities.
Cindy Lee, Advanced Light Source (Chair)
Isabelle Boscaro-Clarke, Diamond Light Source
Silvana Westbury, Lightsources.org
Miriam Arrell, Paul Scherrer Institute PSI
Andrea Taylor, Advanced Light Source / Synchrotron Radiation News
Florentine Krawatzek, BESSY II

184 Lunch seminar: X-Spectrum - High Resolution, High Speed X-Ray Detectors for Synchrotron Applications

14:00 Poster Session incl. Coffee

185 Attosecond Pump-Probe Spectroscopy of Liquid Water

Electronic motion in nature underlies chemical reactions and occurs on the attosecond timescale. Attosecond snapshots of evolving electronic structure during light-induced chemical reactions have been captured with high-harmonic generation probes [1]. However, all x-ray attosecond-pump/attosecond-probe experiments that directly observe electron dynamics in real time with all nuclear motions frozen awaited the advent of intense, attosecond pulses from free-electron lasers [1] delivered as synchronized pairs [2]. Such x-ray pump-probe experiments represent a means to understand, with site- and chemical-selectivity, ionization-induced electronic dynamics in simple gas-phase to complex condensed-phase systems. Employing synchronized two-color x-ray pulse pairs we experimentally developed and theoretically modelled observables for all x-ray attosecond transient absorption spectroscopy (AX-ATAS) where spectroscopic snapshots free from nuclear motion are acquired [4]. Our initial study on pure liquid water resolved a long-standing debate concerning the interpretation of the 1b1 x-ray emission doublet, demonstrating the power of attosecond experiments to also reveal equilibrium structure information. An outlook for studying radiation-induced chemistry from sub-femtosecond to much longer timescales in complex aqueous systems will be presented.

[1] P. Kraus et al., Nature Reviews Chemistry 2, 82–94 (2018).
[2] J. Duris et al., Nature Photonics 14, 30–36 (2020).
[3] Z. Guo et al., Nature Photonics (2024).
[4] S. Li et al., Science 383, 1118-1122 (2024).

Speaker: Linda Young (Eur.UPEX)

16:00 Break

Mikrosymposium 1/4: Beamline Optics and Diagnostics: MS1/4

186 Beam transport optics at ESRF-EBS

Speaker: Raymond Barrett (ESRF)

187 Quick Scanning Channel-Cut Monochromator for Combined Time-Resolved X-ray Diffraction and X-ray Absorption Spectroscopy

The newly constructed Debye beamline at the Swiss Light Source (SLS), available for users after the SLS upgrade mid-2025, is aiming at X-ray absorption spectroscopy and X-ray diffraction analysis to probe the chemical and electronic structure of functional materials under operating conditions. As part of the optical system, a new quick scanning channel-cut monochromator with its control system was developed, providing quasi-simultaneous X-ray absorption spectroscopy (XAS) and X-ray diffraction analysis (XRD). The monochromator is equipped with liquid nitrogen cooled Si(111) and Si(311) channel-cut crystals giving an operational energy range of 4.5 keV to 60 keV. A cutting-edge motion control system provides a diverse range of control options, facilitating Quick-scanning Extended X-ray Absorption Fine Structure (QEXAFS) through sinusoidal motion and custom trajectories as well as precise step-scanning measurements, all seamlessly executed with the same direct-drive motor.

The Bragg axis is controlled by a direct-drive servo motor installed on the atmospheric side of the vacuum chamber and the motion is transferred into the vacuum chamber by a standard ferrofluidic-sealed rotary feedthrough. A rotary encoder mounted next to the crystal stage provides angular feedback to the control loop giving accurately the crystal orientation with a resolution of 0.13 µrad (Figure 1). The control system was evaluated to provide the best available angular accuracy resulting in a stand still position error of ± 1 encoder step after a settling time of well below one second, without the need of physical brakes or goniometers. To realize QEXAFS mode, precise motion with top speeds of up to 100 deg/s or 50 milliseconds per spectrum can be achieved.

A significant improvement on today’s monochromators is the software of the motion controller, resulting in complex motion sequences that are easy to program for the user (Figure 2). A standard set of controls are available, from manual control of the Bragg angle to sinusoidal oscillation for combined XAS/XRD measurements or step-scanning. An additional operational mode has been implemented to program customizable trajectories allowing for variable speeds during an XAS scan, thereby enhancing the data quality in the EXAFS region through progressively slowing the motion, envisioned to provide significant improvement for fluorescence detected XAS collected with continuous motion. To simplify the data acquisition and processing pipeline, precise position triggered signals are emitted from the motion controller for accurately delimiting the individual QEXAFS scans and triggering the XRD detector as well as real time data reduction of QEXAFS scans.

Speaker: Stephan Hitz (Paul Scherrer Institut)

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188 Development of Monolithic Piezoelectric Deformable Mirror Based on Single-Crystal Lithium Niobate

X-ray nanospectroscopy offers the capability to analyze various information such as elements and chemical states with high spatial resolution. Enhancing the sensitivity and spatial resolution requires the use of X-ray focusing optics. Among these optics, X-ray total-reflection mirrors are promising due to their high reflectivity, low chromatic aberration, and excellent radiation hardness. However, one limitation is that the optical parameters cannot be changed depending on the sample used or the experimental conditions.
To overcome this limitation, deformable mirrors (DMs) have been developed that can change the shape of their reflecting surfaces. In particular, high-precision piezoelectric bimorph mirrors, employing piezoelectric actuators bonded to the mirror substrate, have been widely used, and have successfully changed the X-ray beam size[1]. However, conventional DMs face problems related to the amount of deformation. In the DMs, the piezoelectric element must be bonded to the mirror substrate. Therefore, the thickness of the DM cannot be reduced, imposing limitations on the extent of deformation.
To overcome this problem, we propose a novel DM based on lithium niobate (LN). LN’ surface can be atomically smoothed, enabling the development of monolithic DMs where an LN plate serves as both the mirror surface and driving force for deformation[2]. We also utilized the domain inversion property of LN[3]. Heating LN near the Curie temperature allows for domain inversion along the substrate thickness direction. As a result, a practical bimorph structure could be generated within the monolithic LN (Fig.(a)). Consequently, an ultrathin bimorph mirror capable of dynamic deformation without adhesion could be constructed.
Figure (b) shows the LN DM with a thickness of 0.5 mm. The mirror was heated near the Curie temperature. The curvature of the deformation, calculated using the finite element method, was 0.14 km-1/V, which is at least 3 times larger than that of the conventional type. An experiment to change the X-ray beam size was performed at BL29XU of SPring-8. In the tightly focused X-ray mode, the mirror shape could be precisely controlled with a high precision of 3 nm, and a diffraction-limited focusing size of 200 nm in full width at half maximum was achieved (Fig. (c)). Furthermore, the DM also succeeded in forming a beam wider than 1 mm by significantly deforming into a convex shape.
References
[1] S. Matsuyama et al., Sci. Rep., 6, 24801 (2016).
[2] T. Inoue et al., Optica, Accepted (2024).
[3] K. Nakamura et al., Appl. Phys. Lett., 50, 1413 (1987).
Figure (a)Schematic diagram of the deformable mirror. (b) A picture of the deformable mirror.
(c) Measured beam intensity profile.

Speaker: Takato Inoue (Nagoya University)

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189 Operation of Photo Electron Spectrometers for Non-invasive Photon Diagnostics at the European X-ray Free-Electron Laser

Angle resolved photo-electron spectrometers with micro-channel plate detectors and combined with fast digitizer electronics are versatile and powerful devices for providing both soft and hard X-ray non-invasive single shot photon diagnostics at MHz repetition rate X-ray free-electron lasers.
Hard X-ray beamlines imposes specific design challenges due to poor photo-ionization cross-section and very high photo-electron velocities.
Furthermore, recent advancements in machine learning enables resolution enhancement by training the photo-electron spectrometer together with an invasive high resolution spectrometer which generates a response function model.

Speaker: Joakim Laksman (Eur.XFEL (European XFEL))

190 Advances in X-ray Optics Technology of HEPS

High Energy Photon Source (HEPS), the fourth-generation synchrotron radiation facility under construction in Beijing, is designed to operate at an electron energy of 6 GeV with an emittance lower than 60 pm·rad. The high-quality X-ray near diffraction limit presents unprecedented challenges for optical technology. This presentation will provide a comprehensive overview of the current state of research and development in X-ray optical technology at HEPS, including areas such as optical metrology, fabrication, and manipulation.

Speaker: Ming Li

191 Characterization of the LCLS-II X-rays with Imagers, Power Meters and Fluorescence Intensity Monitors

The LCLS-II superconducting accelerator has begun operations and has produced x-rays since August 2024. The initial parameters are a photon energy range from 250 eV to 3.8 keV and a maximum repetition rate of 1 kHz. The absorption edges of solid filters were used to calibrate the photon energy and evaluate the FEL bandwidth from the hard x-ray undulator. The observed aluminum K absorption edge is shown in figure 1. A power meter measured the pulse energy at 3 keV. Imagers have determined the x-ray beam dimensions and the divergence. Power meters have ascertained the beamline transmission at the TMO and RIX instruments. The Fluorescence Intensity Monitor (FIM) provides a normalization of the intensity at the RIX endstations. The accuracy of the FIM has been improved by an analysis of the entire detector waveforms.

Speaker: Philip Heimann (SLAC)

Al_edge_fig_v2.jpeg

192 Design, Fabrication, and Testing of Refractive Axicons for X-ray Microscopy Applications

Full-field Transmission X-ray Microscopy (TXM) is a powerful imaging technique widely used in material, energy, and biological sciences. Synchrotron-based TXM systems offer exceptional spatial resolution in the tens of nanometers range, along with remarkable three-dimensional non-destructive nanoimaging capabilities. A crucial component in TXM setups is the condenser, which can be of different type such as glass capillaries or diffractive beam shaping condensers. This optical component is responsible for converging the x-ray beam to illuminate the sample area.
With synchrotron facilities worldwide undergoing upgrades towards low-emittance sources, TXM systems face new challenges and opportunities. Shrinking x-ray beam dimensions demand innovative approaches in fabricating condenser elements to match their reduced size effectively. Additionally, reduced beam divergence from these advanced sources may constrain the numerical aperture of TXM systems, potentially affecting overall resolution.
This study introduces a novel approach utilizing refractive axicons to shape the incoming x-ray beam, matching it with the combined ring-shaped aperture of a condenser and the central stop. Through a comprehensive design approach, incorporating analytical methodologies and numerical simulations, we demonstrate the efficacy of cone and sawtooth axicons in shaping x-ray beams for optimal performance across a range of photon energies and source sizes.
Experimental validation, conducted at the TOMCAT beamline of the Swiss Light Source, showcases the practical implementation of cone and sawtooth axicons manufactured via cutting-edge two-photon polymerization 3D printing techniques. Our results indicate the relative merits of each axicon design, highlighting factors such as sensitivity to photon energy drifts and intensity distribution uniformity. Importantly, these findings serve as a blueprint for designing and optimizing TXM systems tailored for next-generation light sources, including upcoming facilities like I-TOMCAT and others undergoing synchrotron upgrades worldwide, to empower the broader synchrotron community in harnessing the full potential of TXM for advanced scientific investigations.
Reference

Speaker: Nazanin Samadi (DESY)

Mikrosymposium 12/2: Time Resolved Techniques: MS12/2

193 Few-femtosecond synchronisation at EuXFEL and FLASH

We report latest advancements in achieving drift-free, single-digit femtosecond synchronisation at the free-electron laser (FEL) facilities European XFEL and FLASH. Achieving this level of facility-wide stabilisation, and ultimately enabling femtosecond temporal resolution in user experiments at the scientific instruments necessitates not only tight synchronisation of optical lasers (e.g., pump-probe, photoinjector) but also the linear accelerator (linac) itself through LLRF reference control and active feedback on electron bunch arrival time, which, in turn, determines the X-ray photon pulse arrival time. Moreover, we have implemented novel optical laser pulse arrival time monitors for the compensation of drift at the interaction points of the experiments caused by laser pulse amplification, transportation, and manipulation. The entire synchronisation system, based on the distribution of an ultra-stable optical reference signal on an actively stabilised network of optical fibres, has not only been benchmarked independently, but additionally including the linac, and finally pump-probe experiments. Furthermore, the influence of natural and civilisation-induced seismic activities on the synchronisation performance has also been evaluated. Based on our findings, developments for sub-femtosecond synchronisation got under way for future utilisation of the accelerator’s capabilities.

Speaker: Sebastian Schulz (Deutsches Elektronen-Synchrotron)

194 Leveraging novel detector technology and new timing modes at CHESS for in-situ and time-resolved studies

Speaker: Katherine Shanks

195 Novel Experiments Employing Transverse Resonant Island Buckets (TRIBs)

We report here on the new scientific possibilities that have recently been opened up from new accelerator physics developments - the operation of a synchrotron radiation source in a so-called TRIBs mode [1]. Here, the electron beam moves on a different closed orbit in the storage ring, which only closes after several (e.g. 3) turns, but the electrons run on different paths through the storage ring on their way. Apart from the fact that single bunches with correspondingly longer repetition times can now be kicked to such a second orbit for time-resolved experiments, we show here, based on experiments at BESSY II and predictions for 4th generation sources such as BESSY III, how to significantly improve X-ray experiments such as XAS, XMCD and Imaging by TRIBs and by cleverly exploiting the properties of the beamlines and the time structure of the electron beam. By utilizing the full brilliance of the entire multibunch filling pattern we show here experimental results on MHz helicity flips at elliptical IDs [2], MHz pre-edge normalization for XAS, XMCD and Imagine applications [3] as well as I0 normalization from the previous turn for imaging spectroscopy and other methods. Most methods benefit from the fact that the pointing of the electron and, hence, the photon beam stands almost still at consecutive turns of electrons in the ring enabling new approaches to a quantitative characterization of samples. Simulations including ray tracing down to the final focus show the even improved suitability of the method for BESSY III [4] and other 4th generation light sources.

[1] M. Ries et al., Transverse Resonance Island Buckets at the MLS and BESSY II, Proc. IPAC 2015, Richmond, VA, USA, p.138, doi:10.18429/JACoW-IPAC2015-MOPWA021
[2] K. Holldack et al., Flipping the helicity of X-rays from an undulator at unprecedented speed Communications Physics, 3, 61 (2020), https://doi.org/10.1038/s42005-020-0331-5
[3] K. Holldack et al., Two-color synchrotron X-ray spectroscopy based on transverse resonance island buckets, Scientific Reports, 12, 14876 (2022), https://doi.org/10.1038/s41598-022-19100-z
[4] M. Arlandoo et al., A first attempt at implementing TRIBs in BESSY III design lattice, Proc. IPAC 2022, Bangkok, Thailand, p. 2560, doi:10.18429/JACoW-IPAC2022-THPOPT003

Speaker: Karsten Holldack (Helmholtz-Zentrum Berlin)

196 Time-Resolution and Timing Correction at the Femtosecond X-ray Experiments Instrument of the European XFEL

Hard X-ray free-electron lasers (XFELs) have been a powerful tool for investigating ultrafast dynamics for more than ten years, with ever-improving capabilities in measuring on faster and faster timescales. The unique combination of Angstrom wavelengths and sub-100 fs pulse durations has proven especially important for probing the interplay between electronic and structural dynamics in a broad variety of samples. To observe such subtle and complicated processes, an ultrafast optical pump pulse is often used to initiate the dynamics, with femtosecond laser sources covering the UV to visible spectral range commonly being used, followed by an X-ray probe pulse. European XFEL can provide high intensity X-ray pulses with around 109 to 1012 photons/pulse (bandwidth dependent), high repetition rates from 100 kHz up to 4.5 MHz femtosecond X-ray pulse with 10 trains per second1. These X-ray pulse durations are generally around 50 fs (FWHM) but can be made substantially shorter, to the few fs regime, with different accelerator configurations. The facility pump-probe laser system is also capable of dynamically matching the X-ray pattern, with two default operation modes of 50 and 15 fs (FWHM) 800 nm pulses ranging from hundreds of uJs to mJ level (repetition rate dependent)2. These excellent characteristics make EuXFEL an attractive facility to perform ultrafast femtosecond time resolution research. However, the femtosecond time delay between the X-ray and optical laser pulses needs to be monitored as precisely as possible to get a relatively more accurate value from which to improve the time resolution. This relative timing stability can be affected by both slow (drift) and fast (jitter) components that can originate from a number of sources. One standard approach to address this issue is to measure on a shot-to-shot basis the relative timing difference between the laser and X-rays. Once the pulse-resolved timing jitter has been measured, the pump-probe time delays of each pulse can then be corrected, removing this contribution from the measurement3.
In this talk, we will present the Femtosecond X-ray Experiments (FXE) instrument4,5, which is focused on measuring ultrafast dynamics in the condensed phase using a broad variety of hard X-ray spectroscopy and scattering techniques. We will present the results of several measurements on solution-phase metal-centered molecular complexes6 where the time resolution of the instrument is explored, and the contributions of the various sources of timing instability are identified and measured. The results will focus on the deployment of the pulse arrival monitor (PAM) laser-X-ray timing diagnostic7, with an explanation as to how it is integrated into the parallel measurement capabilities of the instrument, and how the complementary beam arrival monitor (BAM) accelerator diagnostic information can be used as a complementary timing diagnostic. The photochemical dynamics reported include the X-ray emission spectrum and X-ray scattering, measured in parallel with both BAM and PAM diagnostics, providing an improvement in the timing resolution. The presentation will conclude with a summary of the important elements for achieving good time resolution at the FXE instrument, and an overview of the experimental conditions for achieving this.

1. Decking, W. et al. A MHz-repetition-rate hard X-ray free-electron laser driven by a superconducting linear accelerator. Nat Photonics 14, 391–397 (2020).
2. Pergament, M. et al. High power burst-mode optical parametric amplifier with arbitrary pulse selection. Opt Express 22, 22202 (2014).
3. Hartmann, N. et al. Sub-femtosecond precision measurement of relative X-ray arrival time for free-electron lasers. Nature Photonics 8, 706–709 (2014).
4. Galler, A. et al. Scientific instrument Femtosecond X-ray Experiments (FXE): instrumentation and baseline experimental capabilities1. J Synchrotron Radiat 26, 1432–1447 (2019).
5. Khakhulin, D. et al. Ultrafast X-ray Photochemistry at European XFEL: Capabilities of the Femtosecond X-ray Experiments (FXE) Instrument. Appl Sci 10, 995 (2020).
6. Lima, F. A. et al. Experimental capabilities for liquid jet samples at sub‐MHz rates at the FXE Instrument at European XFEL. J. Synchrotron Radiat. 30, (2023).
7. M. R. Bionta, M. R. et al. Spectral encoding method for measuring the relative arrival time between x-ray/optical pulses. Rev. Sci. Instrum. 85, 083116 (2014).

Speaker: Hao Wang (Eur.XFEL (European XFEL))

197 Real-Time Observation of Intermediates at the Solid-liquid Interface of Catalyst Electrode Using Wavelength-Dispersive Soft X-ray Absorption Spectroscopy

A real-time measurement method by soft X-ray absorption spectroscopy (XAS) was developed to observe the chemical reaction under operando condition [1]. In addition, a dedicated cell for the method was prepared for real-time observation of the chemical reaction at the solid-liquid interface of the (photo)electrode for the oxygen evolution reaction (OER) of water electrolysis. Hydrogen generation through water electrolysis is one of the most popular research fields for achieving carbon neutrality. In particular, the electrode for OER is a performance bottleneck compared with the hydrogen evolution reaction electrode; therefore, improving the OER performance is important for enhancing the overall system performance. For the purpose, operando evaluation focusing on the solid–liquid interface conditions is key to elucidating the chemical states of the catalytic material surface and identifying the intermediate species at the surface.
In this study, CoO_x and TiO₂ as OER catalysts were observed in real time using fluorescence-yield soft X-ray XAS. Oxygen K-edge XAS was observed during linear sweep voltammetry for OER, and with UV light on or off (in the case of TiO₂). The spectra during the reaction were obtained every 3 s. Alternation of the spectra appeared during the potential sweep, and the peak intensity differed between the cases with UV light on and off for TiO₂. This spectral change can be attributed to the intermediates formed during the (photo)catalytic reaction at the solid–liquid interface.
The present technique can be applied to a wide range of analyses of (photo-) electrocatalysis and electrochemical reactions at solid–liquid interfaces to observe their products and intermediates during the reaction.

Figure 1 Schematic image of the dedicated electrochemical cell for measurement using wavelength-dispersive XAS. The XAS spectra of O K-edge were obtained in real time, and the spectrum changed according to the applied potential. The right side of the figure shows the change in intensity of O K-edge of CoO_x over time during the potential sweep. [2], [3]

References:
[1] K. Amemiya et al., Rev. Sci. Instrum. 91, 093104 (2020).
[2] K. Sakata, K. Amemiya, Chem. Lett. 50, 1710 (2021).
[3] K. Sakata, K. Amemiya, Electrochem. Commun. 157, 107627 (2023).

Speaker: Kaoruho Sakata (High Energy Accelerator Research Organization)

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198 Time-Resolved Luminescence Spectroscopy of Wide Gap Insulators under VUV Excitation at MAX IV and PETRA III Storage Rings

The international luminescence community is in an excellent situation concerning the experimental conditions for research of wide gap materials under VUV excitation. The FinEstBeAMS beamline at MAX IV equipped with a moveable luminescence end-station is in operation since 2019 [1]. The luminescence end-station of the P66 beamline at PETRA III has in permanent user operation since 2022. Although many technical features and solutions are analogous, there are several relevant distinct features from a user’s point of view. The FinEstBeAMS beamline has a grazing incidence (GI) optical scheme providing a high photon flux > 1011 ph/s in the energy range of 4.5 – 1000 eV from an elliptically polarizing undulator source. The P66 is built on a dipole magnet source with a 2 m NI monochromator equipped with Al and Pt coated gratings [2]. It operates in the energy range of 3.7 – 40 eV with photon flux < 1010 ph/s for Al and < 109 ph/s for Pt grating, respectively. Also, the focal spot sizes are typical for undulator and dipole magnet beamlines, being of nearly 0.2 x 0.2 mm and 4 x 0.5 mm slit shape, respectively. Thus, the samples studied at FinEstBeAMS are exposed to the incident radiation at much harsher conditions leading to their degradation and luminescence fading during the measurements. On the other hand, a suppression of higher order radiation due to GI is a bigger challenge for the FinEstBeAMS than for P66 beamline. The typical time resolution achieved  180 ps is comparable for both setups, but it is available only in a single bunch mode (time interval 320 ns) at MAX IV and in a timing mode (40 bunches at 192 ns intervals) at PETRA III. Such peculiarities must be taken into account while planning photoluminescence research at different beamlines.
Our research team investigates the properties of wide gap materials for various applications at both facilities. The wide gap fluoride scintillators are of interest for ultrafast timing applications due to intrinsic cross- and intraband luminescence [3]. The UV-C emissions of Pr3+ ions have also wide range of applications from increasing efficiency of radiotherapy in medicine to novel light sources for various purposes. In order to fulfil the expectations set by the applications, the basic relaxation processes of excitations populating Pr3+ states have been studied in various hosts [4, 5]. Our contribution will focus on findings in the studies of the above-mentioned wide gap materials by time-resolved luminescence and other methods at the P66 and FinEstBeAMS beamlines.
References
[1] V. Pankratov, R. Pärna, M. Kirm, et al., Radiation Measurements 121 (2019) 91–98.
[2] S. I. Omelkov, K Chernenko, J. C. Ekström, et al., J. Phys.: Conf. Series 2380 (2022) 012135.
[3] J. Saaring, A. Vanetsev, K. Chernenko, et al., J. Alloys Compd. 883 (2021) 160916.
[4] J. Kappelhoff, J.-N. Keil, M. Kirm, et al., Chemical Physics 562 (2022) 111646.
[5] I. Romet, É. Tichy-Rács, K. Lengyel, et al., J. Luminescence 265 (2024) 120216.

Speaker: Marco Kirm (Institute of Physics, University of Tartu)

Kirm et al _VUV_spectroscopy_SRI2024_final.pdf

199 New Insights Into the Laser-Assisted Photoelectric Effect from Solid-State Surfaces

Recent advances in high-intensity ultrafast X-ray sources enable a new era of time-resolved pump-probe experiments, revealing hitherto inaccessible information about the interactions of photons with surfaces and the electronic dynamics they induce. Femtosecond time-resolved laser-assisted photoemission (tr-LAPE) provides a deeper understanding of the very foundations of the surface photoemission process. When X-ray and optical laser pulses overlap in time and space, the photo-ejected electron is accelerated by the intense optical laser field, reflecting the dynamics of the laser-surface interaction. This leads to the creation of sidebands in the photoelectron spectrum corresponding to the absorption and stimulated emission of photons in the laser field.

We present a systematic femtosecond time-resolved investigation of the LAPE effect in two similar metallic solids - W(110) and Pt(111) single crystals - investigated by ultrafast X-ray photoemission spectroscopy at the soft X-ray free-electron laser FLASH at DESY in Hamburg (cf. Fig. 1). Surprisingly pronounced differences in the LAPE spectra of the two materials measured under identical conditions are observed. While tungsten exhibits strong sidebands up to the sixth order, sidebands in platinum are barely discernable beyond the second order. The unexpected observations are explained on a semi-quantitative level by analyzing the dynamic dielectric responses of the two materials, demonstrating new insight into the time-dependent IR field strength in the surface region of the metals, and the dynamics of the light-matter interaction. Calculations using the strong-field approximation show that an intrinsic, near-surface IR laser field enhancement by a factor of 4 is the root cause for the larger number of sidebands in tungsten compared to platinum.

These new insights demonstrate the exceptional sensitivity of femtosecond tr-LAPE measurements to the dielectric properties of solids in a sub-nm thick surface layer. The findings may inspire new techniques to monitor electronic and lattice dynamics in surface regions and help to gain a deeper understanding of surface electromagnetic fields including local fields near chemisorbed atoms and molecules.

Moreover, a detailed understanding of LAPE contributions in high-resolution pump-probe photoemission spectroscopy is a prerequisite for correctly interpreting a growing number of pump-probe experiments at next-generation, high repetition-rate light sources. Therefore, the new results provide new opportunities for even more challenging experimental and theoretical investigations utilizing ultrafast and intense laser fields.

Figure caption:
Fig. 1: Femtosecond time-resolved XPS spectra of the (A) W 4f and (B) Pt 4f photolines as a function of time-delay (vertical) and binding energy (horizontal).

Speaker: Friedrich Roth (XFEL_EET (Soft X-Ray Port))

Abstract_LAPE_SRI_V2.pdf

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Mikrosymposium 3/2: Data, Automation and the Use of AI: MS3/2

200 The mamba software and AI for science project for HEPS

Speaker: Yi Zhang (Institute of High Energy Physics)

201 Beamline-conscious Bayesian optimization for synchrotron facilities

Autonomous methods to align beamlines can decrease the amount of time spent on diagnostics, and also uncover better global optima leading to better beam quality. Bayesian optimization is a machine learning-based algorithm well-suited for high-dimensional, expensive-to-sample, and potentially noisy optimization problems, and it has been successfully implemented to autonomously align beamlines at several synchrotron facilities. However, there are beamline-specific obstacles that can hinder the robustness and efficiency of these efforts, meaning that most are tailored to a narrow context of optimization problems. In this talk, I outline these obstacles and their solutions, and show that it is possible to construct an adaptable, generalized framework for autonomous alignment that performs well at many different kinds of beamlines across different facilities. I present blop, a python package based on (but not exclusive to) the Bluesky framework for experiment orchestration. I outline its application to different optimization problems at several light sources (ALS, APS, NSLS-II, LCLS). I discuss the prospect of a unified, collaborative approach to beamline automation.

Speaker: Thomas Morris (Brookhaven National Laboratory)

202 Managing and Curating Data Flows at PETRA IV and III

The upgrade of the existing PETRA-III synchrotron at DESY to a fourth-generation light source, PETRA-IV, includes not only an increase in brightness but also a new and expanded portfolio of instruments and an updated business model delivering results to non-expert users more promptly than today. Indeed, this business model is already under development at select PETRA-III instruments.
The expectation that a majority of users will be experts in their own scientific fields but not necessarily experts in photon science data analysis highlights the need for the provision of high-level integrated data analysis and data management services to users. We envisage the provision of analytic services to the wider scientific community wherein the timely provision of analysed data to users at conclusion of the measurement is essential. With data volumes exceeding the logistical capacity of most users, and especially non-expert users, these services must be provided by the facility or similar large scale research infrastructure. Provision must also be made for commercial measurement services on top of the same core infrastructure where data must be treated in confidence rather than being destined for open publication.
Prompt analysis of data will become a practical necessity. In the near future a good fraction of the planned instruments will generate in excess of a petabyte of data per day during routine operation, a data volume that already occurs today at some select instruments. Retaining all data on disk for 6 months and on tape for 10 years is no longer economically feasible. Instead, rapid analysis using validated pipelines is required to reduce archived data volumes while providing faster turnaround of results to users performing routine measurements.
Integrated data analysis and data management services are required at the facility to support the full data life cycle from proposal through data taking and on to data analysis, publication, archiving. This includes integrated collection of metadata such as persistent sample identifiers alongside the data, through to infrastructure for enabling data to be open for re-use by the wider community according to FAIR principles (FAIR data stands for Findable, Accessible, Interoperable and Reusable data).

Speaker: Anton Barty (FS-SC (Scientific computing))

203 Multimodal Data Analysis by Artificial Intelligence for Synchrotron Radiation Experiments

Synchrotron radiation (SR) light sources provide precise and deep insights that have been driving cutting-edge scientific research. Facing to SR scientific big data challenge, it is urgent to develop artificial intelligence (AI) analysis methods to enhance research efficiency including novel material discovery[1]. In this talk, I will focus on AI analysis methods for multimodal SR data including image and diffraction data. First, regarding image data, we implement a novel localization quantitative analysis method based on deep learning to analyze X-ray nano-computed tomography (Nano-CT). We achieve localization three-dimensional quantitative Nano-CT imaging analysis of single-cell HfO2 nanoparticles and demonstrate the notable effect of the nanoparticles in tumor treatment[2]. Our approaches show the potential to explore the localization quantitative three-dimensional distribution information of specific molecules at the nanoscale level in Nano-CT. Second, regarding diffraction data, we develop two sets of data-driven and physics-knowledge-driven machine learning (ML) methods to analyze the X-ray diffraction and extract three-dimensional orientation information of nanofibers. The data-driven ML model achieves high accuracy and fast analysis of experimental data and is available to be applied in multi light sources and beamlines[3]. The physics-knowledge-driven ML method enables high-precision, self-supervised, interpretable analysis and lays the foundation for systematic knowledge-driven online scientific big data analysis. Overall, our work aims to analyze multimodal SR data accurately and quickly in real-time through AI algorithms, which support AI for SR-based Science strongly.

Reference:
[1] Qingmeng Li, Rongchang Xing, Linshan Li, Haodong Yao, Liyuan Wu, Lina Zhao. Synchrotron radiation data-driven artificial intelligence approaches in materials discovery. Artificial Intelligence Chemistry, 2(1): 2949-7477, (2024).
[2] Zuoxin Xi, Haodong Yao, Tingfeng Zhang, Zongyi Su, Bing Wang, Weiyue Feng, Qiumei Pu, Lina Zhao. Quantitative Three-Dimensional Imaging Analysis of HfO2 NPs in Single Cells Via Deep Learning aided Nano-CT. ACS Nano, under revision, (2024).
[3] Minghui Sun, Zheng Dong, Liyuan Wu, Haodong Yao, Wenchao Niu, Deting Xu, Ping Chen, Himadri S Gupta, Yi Zhang, Yuhui Dong, Chunying Chen, Lina Zhao*. Fast extraction of three-dimensional nanofiber orientation from WAXD patterns using machine learning, IUCrJ, 10, 3 (2023).

Speaker: Lina Zhao (The institute of High Energy Physics CAS)

204 Jungfraujoch: A System for 2 kHz Framerate Data Acquisition with Large Format Detector and Data Processing at 4th-Generation Synchrotrons and X-ray Free Electron Laser Facilities

The ongoing 4th-generation synchrotron source upgrades and new constructions around the world will provide a higher brilliance, enabling scientists to investigate the dynamics of biological structures at shorter timescales and with higher throughput than ever before. Large-area photon counting and integrating detectors with fast framing capabilities and large dynamic range have become a vital tool for cutting-edge synchrotron and XFEL science¹. The exponential increase of generated data, shown in Figure 1 (A), requires efficient methods to manage data online and offline^2,3. At PSI, we developed a single standard-sized server, called Jungfraujoch (Figure 1 (B))⁴, that is capable of handling 40 GB/s data stream and carrying out initial data analysis (spot finding, indexing, azimuthal integration, etc.) from a 9 Mpixel detector at 2 kHz⁵. After successful demonstrations of this powerful server with the new PSI JUNGFRAU 9M detector at the PXI beamline at the SLS, we now aim to push forward and show the potential of Jungfraujoch at other sources and with different applications. This drive is especially relevant, given the current upgrade of the SLS to SLS 2.0 – a 4th-generation light source.

To evaluate the compatibility and capability of Jungfraujoch, we present the process of integrating the Jungfraujoch system in a 4th-generation light source (MicroMAX, MAX IV) and an X-ray free-electron laser (XFEL) facility (Cristallina, SwissFEL) along with demonstrations of time-resolved serial crystallography experiments. As we investigate and optimize additional functionalities and gain more experience with integrating Jungfraujoch into different workflows and infrastructures, Jungfraujoch could be a broadly applicable solution for more types of detectors, more beamlines, and more techniques at both Synchrotrons and XFEL facilities.

1. F. Leonarski, S. Redford, A. Mozzanica, et al., Nat. Methods, 15, 799–804 (2018).
2. F. Leonarski, A. Mozzanica, M. Brückner, et al., Struct. Dyn., 7, 014305 (2020).
3. M. Galchenkova, A. Tolstikova, B. Klopprogge, et al., IUCrJ, 11, 190–201 (2024).
4. F. Leonarski, M. Brückner, C. Lopez-Cuenca, et al., J. Synchrotron Rad., 30, 227–234 (2023).
5. F. Leonarski, J. Nan, Z. Matěj, et al., IUCrJ, 10, 729–737 (2023).

Figure 1. (A) Rapid growth of data rates over the past and predicted into the future after the SLS 2.0 upgrade. (B) Jungfraujoch data flow.

Speaker: Jiaxin Duan (PSI)

Jiaxin Duan - SRI2024 - Abstract Figure1.png

205 Machine Learning Applied to Active Collimation in Monolithic Arrays of SDDs

Monolithic arrays of SDDs represent a promising solution for high-rate X-ray spectroscopy detectors at synchrotron beamlines. However, charge sharing near pixel boundaries represents an obstacle for multichannel X-ray fluorescence spectroscopy based on monolithic Silicon Drift Detector (SDD) arrays. While crosstalk is efficiently reduced by traditional mechanical collimation, active area and overall efficiency are compromised. In this work, we propose electronic collimation as a solution, and we will be presenting our research at the upcoming conference.
Experimental measurements were conducted using an ARDESIA-16 detection module, highlighting charge sharing effects through pulsed laser measurements and $^{55}$Fe X-ray source experiments. Following a quantitative evaluation of the entity of charge sharing between neighboring channels, we developed a discrimination and reconstruction algorithm to identify these events and ultimately estimate their total energy by taking into account significant parameters such as rise time and coincidence of events on neighboring channels. This algorithm was effective in minimizing the background continuum while preserving overall efficiency.
Moreover, we integrated machine learning into our approach, aiming to enhance crosstalk mitigation. The combination of discrimination algorithms and machine learning utilizes the shape of step-like events at the output of the charge sensitive amplifier (CSA), their rise time, and the detector timing capabilities for effective charge sharing event identification. This integrated approach not only minimizes background but also recovers useful signals that might be discarded with simpler filters.
Our approach eliminates the need for custom-made mechanical collimators, simplifying the mounting process on SDDs, especially when dealing with narrow pixel pitches. We maximize the effective area beyond what mechanical collimation could achieve via electronic collimation and machine learning, offering an opportunity for improving the performance of SDD-based spectroscopy detectors. Moreover, we recover valuable events from the background and integrate them into the photopeak, restoring active area that is naturally lost as a result of charge sharing effects.

Speaker: Beatrice Pedretti (Politecnico di Milano)

Abstract SRI 2024.pdf

206 Molecular Simulation-Driven Digital Twin Optimization for Synchrotron Radiation Characterization of Solid-State Batteries

All-solid-state lithium-sulfur batteries are hailed as one of the most promising candidates in the realm of battery materials, boasting higher energy density, lower extraction costs, enhanced safety, and improved cycling performance. While synchrotron radiation-based characterization techniques offer insights into the elemental distribution, bonding situations, and local coordination environments of all-solid-state lithium-sulfur batteries, capturing dynamic molecular functional motion remains a critical challenge. This project introduces a novel digital twin methodology to explore the molecular mechanisms governing discharge processes and the dynamic evolution of interfaces across multiple spatiotemporal scales in all-solid-state lithium-sulfur batteries using synchrotron radiation characterization systems. Initially, a potential function is trained for the all-solid-state lithium-sulfur battery system based on deep potential methods, facilitating the construction of an efficient, multiscale molecular simulation digital space conducive to real-time interaction. Additionally, a physical space dedicated to synchrotron radiation characterization experiments for all-solid-state lithium-sulfur batteries is successfully established. Furthermore, a real-time interactive integration of the molecular simulation digital space and the synchrotron radiation characterization physical space is achieved, forming a digital twin system platform, which enables microscopic characterization of multi-stage discharge reactions in all-solid-state lithium-sulfur batteries. Finally, it offers novel insights into the research paradigm of synchrotron radiation characterization for all-solid-state lithium-sulfur batteries.

Speaker: Deting Xu (Institute of High Energy Physics)

Figure.jpg

Mikrosymposium 4/2: New Detector Developments: MS4/2

207 Development of high-efficiency spin-resolved ARPES towards micrometer spatial resolution at HiSOR

Since the discovery of strong spin-orbit coupled materials such as Rashba systems, topological insulators, and Weyl semimetals, spin- and angle-resolved photoemission spectroscopy (SARPES) has become a very important technique to investigate spin-dependent electronic structures. A combination of the electron analyzer with the state-of-the-art spin polarimeter based on a very low energy electron diffraction (VLEED) scheme utilizing the ferromagnetic target allows us to reveal a detailed spin texture in solids. However, in the case of materials possessing magnetic domains or several surface terminations, the presence of multi-domain structures prevents us from obtaining true signals from a single domain. To overcome this problem, the spatial resolution should be improved below the domain size.
At Hiroshima Synchrotron Radiation Center (HiSOR), we constructed two VLEED-based SARPES instruments combined with vacuum ultraviolet (VUV) synchrotron radiation ($h\nu$ = 16 - 80 eV) and 6 eV laser light sources [1-3]. They run stably and are open for users. Recently, we have installed focusing mirrors to improve the spatial resolution. Consequently, the beam spot sizes are remarkably reduced to 500$\times$100 $\mu$m at the VUV beamline and 5$\times$9 $\mu$m at the laser system. These values are one or two orders of magnitude smaller than before the introduction of the focusing mirrors. In this talk, we will present several SARPES results utilizing our aforementioned high-efficiency SARPES systems.

References
[1] T. Okuda $\it et\ al$., Rev. Sci. Instrum. $\bf 82$, 103302 (2011).
[2] T. Okuda $\it et\ al$., J. Electron Spectrosc. Relat. Phenom. $\bf 201$, 23 (2015).
[3] T. Iwata $\it et\ al$., Sci. Rep. $\bf 14$, 127 (2024).

Speaker: Kazuki Sumida (Hiroshima University)

208 The Angular-Resolved Schottky CdTe (ARC) pixel detector for the I15-1 XPDF beamline at Diamond

on behalf of the WP2 LEAPS-INNOV consortium

X-ray Absorption Fine Structure spectroscopy (XAFS) is crucial to investigate the electronic and atomic structure of different kinds of samples [1]. The efficacy of this technique, widely deployed at synchrotron facilities, is constrained by the performance limitations of the current generation of Ge detectors. To perform XAFS measurements, energy-resolving detectors capable of handling high count rates are essential [2]. While efforts have been focused on developing arrays of Silicon Drift Detectors (SDDs), less attention has been given to enhancing the performance of High Purity Germanium (HPGe) detectors for synchrotron applications. HPGe detectors offer better detection efficiency at high energies compared to SDDs.
To address this, a detector consortium under the European project LEAPS-INNOV [3] launched an ambitious R&D program aimed at developing a new generation of multi-element monolithic HPGe detectors specifically tailored for X-ray detection [4]. Two detector prototypes are currently under development and are anticipated to undergo characterization in the second half 2024. Simulations of the detector prototypes have been conducted to optimize the detector performance. Each prototype is equipped with a 10-element monolithic HPGe sensor, one with a 5 mm2 area pixels and another with 20 mm2 area pixels. Additionally, a novel electronic chain has been engineered, allowing crosstalk and charge-sharing correction, and enabling the processing of higher count rates ranging from 20 kcps/mm2 up to 250 kcps/mm2, while preserving reasonable energy resolution and minimizing dead time within the required energy range.
This work presents a comprehensive overview of the detector prototypes, encompassing mechanical design details, HPGe sensor specifications, electronic configurations, and their individual performance. Furthermore, results from simulations aimed at optimizing the detector's functionality are presented and analysed.

Acknowledgement
This project has received funding from the European Union’s Horizon 2020 research and innovation
program under grant agreement No.101004728.

References
[1] G. Bunker, ”Introduction to XAFS: A Practical Guide to X-Ray Absorption Fine Structure Spectroscopy”. Cambridge, U.K., Cambridge Univ. Press, 2010.
[2] N. Tartoni, et al., ”Hexagonal Pad Multichannel Ge X-Ray Spectroscopy Detector Demonstrator: Comprehensive Characterization,” in IEEE Transactions on Nuclear Science, vol. 67, no. 8, pp. 1952-1961, Aug. 2020.
[3] LEAPS pilot to foster open innovation for accelerator-based light sources in Europe, European Union’s Horizon 2020, Grant Agreement No. 101004728.
[4] F. Orsini, et al., “XAFS-DET: a new high throughout X-ray spectroscopy detector system developed for synchrotron applications”, Nucl. Instrum. Meth. A, Volume 1045, 2023, 167600, https://doi.org/10.1016/j.nima.2022.167600.

Speaker: Eva Gimenez-Navarro (Diamond Light Source)

209 Detector Development at ELETTRA

This work reports on the recent activities carried out by the Detector and Instrumentation Laboratory of Elettra Sincrotrone Trieste. Since both the Elettra synchrotron and the Fermi free electron laser are generating photons in the low to medium x-ray energy range from some eV to tenths of keV the activities of the detector and instrumentation laboratory focuses on spectroscopic and imaging photon detectors, which feature high quantum efficiency from below the carbon edge and are operated also in UHV environments.
Regarding low energy imaging detectors the PERCIVAL CMOS (‘Pixelated Energy Resolving CMOS Imager, Versatile and Large’), currently under development by a collaboration of DESY, RAL, Elettra, PAL, DLS and Soleil, aims to address the need for such detectors for synchrotrons and free electron lasers in the soft X-ray regime. Its application to soft X-ray ptychography at the Twinmic beamline will be discussed.
Using the Twinmic beamline instrumentation, future possibilities in complementary imaging modalities, including in-situ atomic force microscopy and spectral imaging with custom-made monolithic and multi-element silicon drift detectors, will be discussed. It’s noteworthy that a 64-channel detector utilizing the latter has been successfully commissioned at Elettra’s XRF beamline.
Element-specific spectral imaging in the medium to hard X-ray energy range has garnered significant interest from the community. Examples of detector and optics based spectral X-ray phase contrast imaging and its translation to compact sources will be discussed briefly. Moreover, first results of a pixelated spectral THz imaging detector based on MEMs resonators will be presented as well.
The majorities of Elettra’s soft x-ray beam lines are employing fast (4 M counts / sec, time resolution of some 10th of ps) and spatially resolving ( < 60 µm) electron detectors and their associated readout electronics, which have been developed in-house and have been tailored to the specific needs of the respective beam line. In addition, devices for in situ beam diagnostics and dose monitoring for synchrotron radiation and FEL beams have been developed and are operated on a daily basis. Moreover, some recent results in basic research on room temperature semiconductors will be discussed.
In this presentation an overview of these devices and their application to specific scientific applications will be given and, in view of upgrade programs future directions, will be discussed.

Speaker: Ralf-Hendrik Menk (Elettra Sincrotrone Trieste, INFN Trieste, Midsweden University)

210 A Transition Edge Sensor Spectrometer at BESSY II for Impurity Level X-ray Absorption and Emission Spectroscopy of Solid State and Molecular Systems

A new experimental setup, which includes a highly photon sensitive spectrometer based
on superconducting transition edge sensors (TES) is under commissioning at BESSY II.
The setup is dedicated to XAS, XES and RIXS experiments in the soft X-ray regime with a
strong emphasis on the study of low concentration systems, which can be divided into two
main themes: 1) solids and low dimensional systems and 2) molecular systems in solution.
The principle of a TES detector is based on the abrupt normal metal –
superconductor transition edge of a superconducting sensor as an energy dispersive and
ultrasensitive photon detector with a collecting efficiency orders of magnitude higher than
grating-based spectrometers [1,2]. The present detector consists of an array of 256
sensors in a compact design mounted on a closed-cycle dilution refrigerator to reach the
operation temperature of 53 mK, and targets an energy resolution of 0.5 eV FWHM for
energies below 1 keV. The experimental setup is installed at the UE52-SGM beamline with
full polarization control. The relatively large (1-6 mm 2) beam size at the sample position
allows low sample damage measurements of fragile systems. The dedicated UHV sample
chamber is designed for the preparation of low-dimensional solid state systems as well as
for the insertion of molecular systems in frozen solutions.
In this presentation, after an introduction on the principle of the TES technology, I
will show the specific characteristics of the spectrometer deployed at BESSY II and the
results of the first tests with the full experimental setup.

Speaker: Régis Decker (Helmholtz-Zentrum Berlin)

abstract_decker_SRI.pdf

211 Development of Sensors for Soft X-ray Hybrid Detectors: Current Status and Future Improvements

Hybrid detectors for hard X-rays developed at the Paul Scherrer Institute (PSI) have demonstrated outstanding performance in terms of fast frame rate, large dynamic range, large area, stability, reliability, and ease of use. To enable these features also for soft X-rays, two main limitations of state-of-the-art detectors have to be addressed: low quantum efficiency and low signal-to-noise ratio. In collaboration with Fondazione Bruno Kessler (Trento, Italy) and PSI, we are trying to address these challenges by optimizing sensor technology. Two required technologies for soft X-ray sensors for hybrid detectors are currently under development: the thin entrance window (TEW) technology and the optimization of the Low Gain Avalanche Diode (LGAD) technology for X-ray detection. The former increases quantum efficiency in the soft X-ray energy regime, and the latter improves the detector's signal-to-noise ratio by increasing the signal amplitude inside the sensor through a charge multiplication process, which enables single photon detection. First measurement results are beyond expectations: the best quantum efficiency achieved so far is greater than 80% down to about 250 eV; the single-photon detection using the developed LGAD sensors has been demonstrated down to 390 eV. The first ptychography experiment using the developed LGAD sensor with the EIGER readout ASIC has been performed by our collaborators at the SIM beamline with 700 eV soft X-rays. It has shown outstanding results: a resolution of a few nanometres on magnetic structures is obtained. Another application that will profit from these developments is RIXS exploiting interpolation, the feasibility of which has also been demonstrated.

The presentation will discuss the status, achievements, and future improvements of soft X-ray LGAD sensors with TEW.

Speaker: Jiaguo Zhang (Paul Scherrer Institut)

212 Advancing Soft X-ray Spectroscopy with a High-Efficiency TES Spectrometer at SSRL

At SSRL, we employ a transition-edge sensor (TES) spectrometer for soft X-ray spectroscopy, including XAS, XES, and RIXS. While offering a moderate energy resolution of ~1.5 eV FWHM, the TES excels in detection efficiency and broad spectral coverage. These strengths have proven valuable in tackling challenging samples, such as those susceptible to radiation damage and extremely dilute frozen solutions (less than 1 mM), at a wiggler beamline. Importantly, the TES spectrometer is available to the general user program, enabling a wide range of scientific investigations. With the recent relocation of the TES spectrometer to an undulator beamline, our ongoing research aims to further explore and exploit the innovative capabilities of this spectrometer.

Speaker: Sang-Jun Lee (SLAC National Accelerator Laboratory)

213 MHz-rate Beam Position and Pulse Energy Measurements with a Diamond Sensor at European XFEL

The diagnostics of the X-ray beam properties has a critical importance at the European X-ray Free Electron Laser facility. Besides existing diagnostic components, utilization of a diamond sensor was proposed to achieve radiation-hard, non-invasive beam position and pulse energy measurements for hard X-rays [1]. In particular, at very hard X-rays diamond-based sensors become a useful complement to gas-based devices which lose sensitivity due to significantly reduced gas cross-sections. A semiconductor detector based on a single crystal chemical vapor deposition (scCVD) diamond with a duo-lateral configuration for position sensitivity was proposed and successfully used at the synchrotron environment [2]. The first results obtained with a similar diamond sensor placed in the photon tunnel of European XFEL demonstrates pulse-resolved X-ray beam position within less than 1% uncertainty at 2.25 MHz [3]. The measurements presented in this work were performed with diamond sensors having similar properties and structure but with a different resistive coating. Here pulse-resolved beam intensity and position measurements performed at the Material Imaging and Dynamics (MID) instrument [4] at the European XFEL are presented.

References:

1. T. Roth, W. Freund, U. Boesenberg, G. Carini, S. Song, G. Lefeuvre, A. Goikhman, M. Fischer, M. Schreck, J. Grünert & A. Madsen. J. Synchrotron Rad. 25 Vol 25 (2018), Pg 177-188.
2. K. Desjardins, M. Bordessoule, M. Pomorski. J. Synchrotron Rad.. Vol 25 (2018), Pg 399-406.
3. T. Çonka Yıldız, W. Freund, J. Liu, M. Pomorski and J. Grünert. Optica Vol 10(8) (2023) Pg 963-964.
4. A. Madsen et al. J. Synchrotron Rad. Vol 28 (2021) Pg 637–649.

Speaker: Tuba Conka Yildiz (Eur.XFEL (European XFEL))

19:30 Conference Dinner at River Elbe (on registration only)

Ship starts at 19:30 at Überseebrücke

Dammtor (Messe/CCH): S2 to Altona >>> to Sternschanze (Messe) [1 stop]
Sternschanze (Messe): U3 to Wandsek-Gartenstadt >>> Baumwall (Elbphilharmonie) [4 stops]
Floating docks, Elbpromenade, 20459 Hamburg

Friday 30 August

214 Catching Catalysts in Action

The ability to activate and functionalize C-H bonds in controlled and sustainable fashion remains one of the holy grails of chemistry. It is here that nature provides much inspiration, with enzymes such as methane monooxygenases enabling the direct and selective oxidation of methane to methanol - utilizing either a copper active site in the particulate form or a dinuclear iron site in the soluble form of the enzyme. Our understanding of the nature of these active sites and their mechanisms has greatly benefited from spectroscopic developments. Herein, I will present recent work utilizing both rapid freeze quench and microfluidic mixers to characterize these enzymatic intermediates in methane monooxygenases and lytic polysaccharide monooxygenases. In addition, recent static and time-resolved spectroscopic studies of homogeneous C-H bond activating catalysts will be presented. These will include 2p3d resonant inelastic X-ray scattering (RIXS) spectroscopic studies as a probe of two-state reactivity and femtosecond X-ray absorption (XAS) and X-ray emission (XES) spectroscopic studies of high-valent iron oxos. The implications of these studies for rational catalytic design will be discussed.

Speaker: Serena DeBeer (MPI CEC)

215 Overview Detector developments

While we observe continuous progression of x-ray facilities, detectors remain often a limiting factor in exploiting the potential of these improved sources.
This talk will provide an overview of detector developments with focus on new technologies and experimental needs. Further it will link the evolution of detector concepts to their success and impact in achieving science goals. The increased necessity to integrate approaches for data flow optimization will be discussed. At the end a perspective on the opportunities to develop a common vision and strategy between facilities as well as community building will be presented.

Speaker: Gabriella Carini (Brookhaven National Laboratory)

216 Science and Innovation at SIRIUS

SIRIUS, Brazil's fourth-generation storage ring light source, is managed by the Brazilian Synchrotron Light Laboratory (LNLS) at CNPEM and funded by the Ministry of Science, Technology, and Innovations (MCTI). As Latin America's only synchrotron, SIRIUS offers beamlines spanning from infrared to hard X-rays, accessible to researchers worldwide.

SIRIUS storage ring, operating at 3 GeV with a 100 mA current, features a 5BA magnet lattice designed for high transverse coherence. It supports up to 38 beamlines, with ten currently operational, two in commissioning and two in installation. The initial set of beamlines covers scientific programs and experimental techniques such as CDI, XPCS, μ and nano-CT, μ and nano-XRD, XAFS, SAXS, ARPES, RIXS, PEEM, and XMCD. Innovative advancements in optics, precision mechatronics, detectors, and computing technology support these experimental capabilities.

Since its inception in 2012, SIRIUS has leveraged expertise from UVX, Latin America's first synchrotron. By 2019, SIRIUS had achieved its first stored beam, and by the end of 2021, it had operated at 100 mA with six beamlines open for user commissioning. Regular operations for users began in 2023.

Aligned with Brazil's green economy strategy, SIRIUS prioritizes sustainable innovation and facilitates agriculture, energy, environment, and health research. Early publications highlight a commitment to sustainable development.

In 2023, the Brazilian government approved SIRIUS's second phase that will add ten more beamlines, extending SIRIUS's spectral range into the THz gap and harder X-rays; technical upgrades, such as the current increase to 350 mA; and infrastructure improvements.

Additionally, CNPEM's ORION project will establish Latin America's first Biosafety Level 4 (BLS4) laboratory, integrating advanced synchrotron X-ray bio-imaging techniques to allow scientists to see, in tri-dimensions, how pathogens infect animals and cause diseases, from the cellular up to the organism level.

This presentation will overview current and future advancements in synchrotron science enabled by SIRIUS, highlighting its potential for groundbreaking scientific breakthroughs.

Speaker: Harry Westfahl (Brazilian Synchrotron Light Laboratory (SIRIUS) / CNPEM)

10:15 Coffee Break

Mikrosymposium 14/2: Miscellaneous Topics: MS14/2

217 Angle resolved X-ray spectrometry for dimensional and analytical nanometrology

The rapid advancements in nanoelectronics have led to a profound increase in the complexity of three-dimensional nanostructures utilized in cutting-edge transistor architectures. As this complexity grows, the demand for precise metrology becomes paramount to ensure successful fabrication. X-ray fluorescence techniques, when employed in specific operational modes, emerge as a valuable tool, offering quantitative insights into semiconductor applications. Moreover, these techniques can be seamlessly integrated with metrology pads of typical sizes featuring homogeneous structures.
The implementation of reference-free XRF quantification schemes, alongside physically calibrated instrumentation and excitation spot sizes in the low micrometer [1] or even nanometer range [2], enables the quantitative determination of lateral elemental composition. Notably, this method surpasses electrons in terms of achievable information depth and can thus provide information about sub-surface features of nanoobjects, all achieved without the need for destructive sample preparation.
The application of Grazing Incidence [3] or Grazing Exit X-ray Fluorescence analysis [4] enhances sensitivity to sub-nanometer levels, allowing for precise measurement of dimensional properties in nanostructures. Critical parameters such as line widths or heights can be accurately determined through these techniques. Importantly, both approaches are non-destructive, offering statistically more relevant information compared to transmission electron microscopy, as they average over several nominally identical nanostructures.
In summary, we will show how employing advanced X-ray fluorescence methods can support navigating the intricate landscape of nanoelectronics metrology.

[1] P. Hönicke et al., Nanotechnology (2024) 35, 285702
[2] A. Wählisch et al., Small (2023) 19, 2204943
[3] P. Hönicke et al., Nanotechnology (2020) 31, 505709
[4] P. Hönicke et al., Small (2022) 18, 2105776

Speaker: Philipp Hönicke (Helmholtz-Zentrum Berlin)

Invited_SRI2024_Phoenicke.docx

218 Investigating Nanostructured Surfaces Using a Multi-Method Approach Based on CD-SAXS and GE-XRF

Properties of nanostructured surfaces are determined by their composition,
size and shape. In the semiconductor industry, the continuously shrinking
dimensions of the features and their increasing complexity require innovative metrology solutions. Non-destructive methods with high throughput that are able to assess complex 3D structures are of major importance. Measurement techniques based on light-structure interaction allow fast and non-destructive inspection of structured areas and are already widely used from the infrared to the hard X-ray spectral range.
PTB’s radiometric capabilities allow accessing fluorescence, scattering and reflected signals in a quantitative and traceable manner. Grazing-incidence scattering and fluorescence techniques have been successfully used for the dimensional characterization of line shapes of lamellar gratings and three-dimensional structures, however the beam-footprint in those techniques is larger than the target field under study. We explore the applicability of near-normal-incidence techniques, combining grazing-exit X-ray fluorescence and small-angle X-ray scattering, so-called hybrid metrology, to investigate the material spatial distribution within a nanostructure.

Speaker: Analía Fernández Herrero (Physikalisch-Technische Bundesanstalt (PTB))

219 ASTRA - Tender XAS Beamline at SOLARIS Synchrotron: Reflections on 1 Year of Operation

Since putting into service, the ASTRA beamline at SOLARIS synchrotron (Krakow, Poland) has gained great interest among scientists working on various research topics. Even though ASTRA is a relatively new bending magnet beamline, open for user operation just for 10 months, until April 2024 a total of over 45 experiments were carried out there. As its name ("Absorption Spectroscopy beamline for Tender energy Range and Above") suggests, ASTRA is an X-ray absorption spectroscopy (XAS) beamline. The photon energy range covered by ASTRA reaches from 1 to 15 keV, including the tender and part of the hard energy range of X-rays. The white beam is monochromatized by a modified Lemonnier type double crystal monochromator (DCM) working at high vacuum, which can be equipped with different types of crystals to cover the working energy range: Ge(422), Ge(220), Si(111), Ge(111), InSb(111), Beryl(10¯10) and organic potassium acid phthalate (100) + multilayer. Crystal pairs can be exchanged in less than one hour! The beamline allows measuring XANES/EXAFS spectra at K-edges of important elements such as Si, P, S, Cl, K, Ca and up to Se. Besides, ASTRA`s energy range also includes L-edges of elements up to Bi and some M-edges of heavier elements including U, allowing investigations of a variety of highly relevant materials. XAS spectra are recorded in transmission and fluorescence mode. The beamline is equipped with an X-ray camera, facilitating appropriate sample positioning for XAS with higher data quality and more reliable results. The measurements are controlled by the specially developed program AstraLibra with a user friendly interface and advanced functionalities. Special cells for measuring samples in liquid phase and in dynamic environments (in situ and operando), even in the tender energy range, were developed and successfully used. Implementation of a combination of XAS with Raman spectroscopy at the beamline is in progress. During the presentation technical aspects of the beamline will be discussed and selected results of ex-situ and in-situ experiments will be presented.
Acknowledgments The development of the ASTRA beamline was partly supported within the grant, Innovative Hochschule – Leuchtturm NR - Aus der Höhe in die Breite“ (03-IHS-084) by the Federal Ministry of Education and Research, Germany and within the EU Horizon2020 programme (952148-Sylinda).

Speaker: Alexey Maximenko (National Synchrotron Radiation Centre SOLARIS Jagiellonian University)

220 Utilizing 3D Printed Plastics for High and Ultra-High-Vacuum (UHV) Environments: A Feasibility Study

The demand for cost and time-effective and customizable components for high-vacuum (HV) and ultra-high-vacuum (UHV) systems has prompted exploration into the application of 3D printing technology. This study investigates the viability of utilizing 3D printed plastics in UHV environments by evaluating their outgassing properties. An extensive evaluation of 3D printing materials was caried out, highlighting the best polymer composition candidates using two of the most common 3D printing techniques, Fused Deposition Manufacturing (FDM) and Stereolithography (SLA). Further experimental investigations are conducted to assess the performance of select 3D printed plastics under UHV conditions, focusing on their ability to maintain structural integrity, minimize outgassing, and withstand baking temperatures. Furthermore, residual gas analysis was used to evaluate the materials compatibility with NEG coated systems. The findings suggest that certain 3D printed plastics exhibit promising characteristics for use in HV and UHV systems, with notable examples including polypropylene (PP) and polyether ether ketone (PEEK). A comparison between machined and 3D printed parts demonstrated that challenges such as porosity and surface roughness showed not to be of great concern.

Speaker: Artur Domingues (MAX IV)

221 The Application of Acoustics for Sample Manipulation and Delivery at X-ray Light Sources

Diamond Light Source is actively exploring acoustics for sample manipulation and delivery, primarily for synchrotron beamlines, but also at X-FELs. Sound is being exploited in two key ways: the first is to use acoustic energy to eject and deliver picolitre drops containing protein crystals in the range of 5-50 microns at a repetition rate up to 50KHz on demand; the second is the use of discrete transducers to create ‘acoustic traps’, areas of low pressure surrounded by high pressure. These traps are used to levitate and manipulate samples in both liquid suspension and solid form and present them to the beam. This combination of acoustics also offers the exciting possibility to do mixing experiments, e.g. adding reagents to crystalline sample prior to beam exposure to perform time-resolved diffraction experiments. Light activated experiments can also be carried out as well as reactions requiring heating, creating a ‘virtual test-tube’ where a reaction can take place in free space, free of contamination and with minimal attenuation for data collection. The acoustic ejection system supplied by Polypico is an effective solution for filling the traps with picolitre volumes. Polypico technology has also been exploited in many ways including to deposit substrate for XFEL experiments, loading grids for automated sample delivery both at Diamond and XFELS, high speed filling of TEM grids for CryoEM with the ultimate aim: to supply sample directly on demand at both Synchrotrons and XFELS. The levitation methodology has already proven successful on a number of beamlines with structure solution of lysozyme and insulin demonstrated. These experiments have been carried out utilising an acoustic methodology known as ’Tinylev’ where the focusing of the transducers to create the areas of high and low pressure is achieved mechanically, allowing for simplification of the control/driver electronics. Greater understanding of the stability of the drops contained within these traps has also recently been characterised. Exciting opportunities to explore levitating sample in multiple axis motion is being facilitated by a system developed at UCL called the Acoustofab. Along with this, a Tinylev-type system is also being developed that will use transducers that operate at 300KHz as opposed to 40KHz which will facilitate levitating samples orders of magnitude smaller, a priority for minimising sample consumption.

Speaker: Peter Docker (Diamond Light Source)

300khz tinylev.jpg

acoutofab.jpg

lablelled head.jpg

tinylevstandard.jpg

222 Novel passive resonant structures for precision assembly of synchrotron X-ray optics

Speaker: Jonathan Griffiths (School of Engineering, University of Lincoln, Brayford Way, Brayford Pool, Lincoln, Lincolnshire, LN6 7TS, United Kingdom)

223 First Low-Background MX Experiments Using Closed-Circuit Helium Atmosphere in the XAIRA Beamline at ALBA

The background of the diffraction patterns is one of the main limiting factors to the quality of macromolecular crystallography (MX) experiments, together with the radiation damage and the crystallinity and size of the crystals. In the last decade, the development of the photon-counting detectors has contributed to effectively reduce the background. Other strategies, such as the operation in vacuum or the use of helium to reduce X-ray scattering with air and maximize flux, have been shown to significantly improve the signal-to-noise ratio of diffraction images, especially at high resolutions [1-4]. However, such approaches are not widely spread due to the requirement for specific instrumentation and the difficulty of He manipulation, which compromise the use of the state-of-the-art and standard methods used in MX beamlines.
In response, XAIRA, the new microfocus MX beamline at the ALBA synchrotron light source, aims to deliver optimal diffraction images by enclosing the entire end-station in He atmosphere, including sample environment, cryostream and detector, while still maintaining compatibility with standard MX sample formats and with operation in air. The helium is recovered to an existing He purification plant nearby for sustainability and operation cost reasons. The diffractometer is based on a unique gas flow-bearing goniometer compatible with He and air, and supports fast oscillation experiments, raster scans and helical scans, while allowing a tight sample to detector distance of 70 mm. Both the detector and cryostream can use either helium or nitrogen gas. Micron-sized crystals will be localized by means of a double on-axis visualization comprising a commercial on-axis visualization system and an undrilled, high-magnification microscope for sample imaging at sub-micron resolution. X-ray-based raster scans and AI algorithms are also being developed to guide sample centering.
XAIRA is foreseen to ramp into user operation by end 2024 and aims to provide a highly stable, 3×1 µm2 FWHM size and high flux beam in the 4-14 keV range, to take further advantage of the use of He. A system of 11 interferometers pointing to the focusing optics and key diagnostics will monitor the vibrations and drifts to ensure the beam stability. The beamline optics has been presented previously [5] and includes a novel monochromator design with Si(111) channel-cut and double multilayer mounts, together with new mirror benders equipped with dynamical thermal bump and figure error correctors [6]. Here we present the first MX experiments, which take advantage of most of these instruments.
References
[1] K. Hirata et al., J. Phys. Conf. Ser., vol. 425, no. PART 1, pp. 8–12, 2013. [BL32XU at Spring-8 in He]
[2] M. Hiraki, et al., AIP Conf. Proc., vol. 1741, 2016. [BL-1A at Photon Factory in He]
[3] R. Glaeser et al., Biophys. J., vol. 78, no. 6, pp. 3178–3185, 2000. [He-air comparison in a lab source]
[4] J. Trincao et al., Acta Crystallogr. A, vol. 71, no. a1, pp. s191–s191, 2016. [VMXm BL in vacuum]
[5] J. Juanhuix, et al. SRI2018 conference proceedings. AIP Conf. Proc. 2054, 060032 (2019)
[6] J. Nicolas, et al. Synchr. Rad. News, 2022, 35(2), 14–19

Speaker: Judith Juanhuix (ALBA synchrotron)

2024_LowBackgroundMXExperiments_final.docx

Mikrosymposium 3/3: Data, Automation and the Use of AI: MS3/3

224 Data analysis using Al and HPC at CLS

Integration of high performance computing and machine learning / artificial intelligence into beamline operations is an important step for handling growing data volumes and to increase scientific productivity of users with large or complex datasets. Work to incorporate a new on-premise high performance computing cluster at the Canadian Light Source with beamline data processing and analysis will be presented. This includes AI-based, GPU-accelerated segmentation of CT data; automated MX crystal centering using object detection; HPC-acceleration of MX dataset processing, large multi-dataset, multi-modal spectromicroscopy imaging data analysis; automated interpolation of large unevenly spaced datasets; and automated reconstruction of CT data during beamtime.

Speaker: Stuart Read (Canadian Light Source)

225 ChatGPT and EPICS: Pioneering LLM-Enhanced Control Systems for Synchrotron Beamlines

The BAMline [1] at BESSY II represents a hard X-ray spectroscopy facility enabling non-destructive analysis across diverse research areas like materials science, chemistry, biology, and cultural heritage studies. As a multipurpose beamline serving users from various disciplines, it underscores the necessity of adaptable and efficient control systems to maximize beamline utilization and scientific output.
In this contribution, we detail the innovative integration of ChatGPT [2], OpenAI's state-of-the-art Large Language Model (LLM), with the Experimental Physics and Industrial Control System (EPICS) [3] which underpins the operational framework of the BAMline. This integration leverages the advanced natural language processing (NLP) capabilities of ChatGPT, presenting a revolutionary approach to beamline control that markedly simplifies user interaction. Through this, we facilitate a user-friendly pathway to executing complex experimental setups, eliminating the barrier imposed by conventional scripting languages and the often-challenging graphical user interfaces. This innovation promises to significantly streamline experimental workflows, thereby enhancing the efficiency of scientific research conducted at the beamline.
Further enhancing this user-centric approach, we introduce an advanced graphical user interface (GUI) application. This novel application seamlessly melds the LLM's NLP capabilities with EPICS, thereby enabling researchers to articulate experimental requirements through simple textual or voice commands. This interface interprets these commands to manipulate various beamline components, including but not limited to the Double Crystal Monochromator (DCM), Double Multilayer Monochromator (DMM), as well as various filters and slits. By parsing user input, extracting pertinent parameters, and generating a structured JSON object that reflects the desired device positions and experimental settings, the GUI application bridges the gap between complex control commands and intuitive user interactions. This advancement not only lowers the entry threshold for new users but also streamlines the operational workflow for experienced researchers.
Looking ahead, we aim to extend the system to cover the entire experimental cycle, from setup to data analysis. Using LLMs, one could translate plain-language experiment descriptions into precise operational commands, revolutionizing the research process and making advanced scientific exploration more accessible to a wider community.

[1] Buzanich, A. G., M. Radtke, K. V. Yusenko, T. M. Stawski, A. Kulow, C. T. Cakir, B. Röder, C. Naese, R. Britzke, M. Sintschuk and F. Emmerling (2023). "BAM
-A real-life sample materials research beamline." Journal of Chemical Physics 158(24).
[2] Achiam, J., S. Adler, S. Agarwal, L. Ahmad, I. Akkaya, F. L. Aleman, D. Almeida, J. Altenschmidt, S. Altman and S. Anadkat (2023). "Gpt-4 technical report." arXiv preprint arXiv:2303.08774.
[3] Thuot, M. E., M. Clausen, L. R. Dalesio, T. Katoh, M. E. Kraimer, R. Mueller, H. Shoaee and W. A. Watson (1996). "The success and the future of EPICS." Proceeedings of the Xviii International Linear Accelerator Conference, Vols 1 and 2 96(7): 611-615.

Speaker: Martin Radtke (BAM)

226 Rapid, Online Screening of Complex Phase Spaces Using Bayesian Optimization with Application to SAXS Measurements

Speaker: Khaled Younes (Stanford University)

227 Pydidas: An Integrated Tool for Diffraction Data Analysis

Synchrotron X-ray diffraction (XRD) experiments are a versatile tool in understanding material properties and processes, for example alloy development for lightweight materials or additive manufacturing and for generating data to create digital twin models. The analysis of XRD data, however, is often still the domain of experts because software tools were designed for flexibility with full access to numerous parameters which, in turn, made them not very user-friendly for non-experts.
The python ecosystem includes powerful tools for generic data processing (e.g. fitting) and also for integration of area detector data (pyFAI [1], azint [2]) as well as tools for the visualization (e.g. silx [3]) of (integrated) diffraction data. While some tools also offer graphical user interfaces (e.g. pyAI calibration) or full integrations of specific analyses (e.g. dioptas [4]), our user community was missing a tool both versatile and easy to use.
Helmholtz-Zentrum Hereon’s new software pydidas [5] is designed to broaden the user base for our XRD experiments by delivering a user-friendly and fast processing tool. It is designed to inherently use container data formats (e.g. hdf5) and make use of parallelization. Data browsing and display, experiment calibration, workflow setup, processing and visualization are all available from within pydidas. Emphasis has been placed on an intuitive user interface and accessibility also for non-experts.
To make pydidas useful to a broad community with different analysis requirements, pydidas workflows are based on individual plugins which allows to modify workflows to a high degree. In addition, custom-made plugins can be easily integrated into pydidas to allow also for highly specific workflows which are not covered with its generic functionality.
While pydidas has reached a stable state, we intend to extend the functionality further. For example, a project to include residual stress analysis in pydidas is currently ongoing.
Pydidas is open source software and publicly available.

[1] https://github.com/silx-kit/pyFAI
[2] https://github.com/maxiv-science/azint
[3] https://github.com/silx-kit/silx
[4] https://github.com/Dioptas/Dioptas
[5] http://pydidas.hereon.de

Speaker: Malte Storm (Helmholtz Zentrum Hereon)

228 High-Resolution Phase-Contrast Imaging for Large Samples at Synchrotron Sources with Time-Varying Beam Profiles

One recently introduced method for the exploration of biological specimens and material structure using phase-contrast imaging combines a Talbot Array Illuminator with the UMPA method of phase retrieval [1]. This method has been shown to enable exceptionally high bidirectional sensitivity and high-resolution imaging without requiring prior assumptions about the sample's composition [2]. However, time-dependent variations in the beam profile at synchrotron sources, often caused by movements within the beamline components, the top-up mode of operation, or orbit control of the electron beam, pose significant challenges. These variations can lead to discrepancies between the flat field images captured before the scan and the actual flat field present during the recording of the sample projections. Consequently, structures such as grating patterns or sandpaper textures, used as wavefront markers, are left visible in the flatfield-corrected images, compromising image quality and quantitative accuracy.
Recently, the eigenflat-optimization approach has been developed to address this issue by decomposing a group of recorded flatfields into eigencomponents and fitting a combination of them to the sample projection using a sample-free region [3]. The method is effective for smaller specimens but falls short when imaging larger samples using multiple views stitched together. While the leftmost and rightmost views have an empty reference area, this is not the case for the middle views, where the sample covers the entire field of view – a problem also encountered in scans focused on specific regions of interest. In both scenarios, the original eigenflat method is not applicable, and artifacts degrade the image quality. In response to this limitation, we introduce a novel approach that extends the capabilities of eigenflat-optimization to accommodate larger samples without the necessity of an empty reference region. By using a new approach for the optimization step, our method generates eigenflat weights for the central portions of the sample, thus enabling the seamless stitching of multiple views and enhancing the overall image quality. This approach allowed us to record a high-resolution image of a full rat brain, 15 mm in diameter, at beamline P07 – operated by Hereon – at PETRA III (DESY, Hamburg), despite the limited 6 mm horizontal field of view. Furthermore, we have incorporated deformable registration techniques to refine the alignment and overlay of partial scans, thereby better compensating for sample deformation caused by radiation damage and detector distortion. Consequently, our method offers a robust solution to the challenges posed in investigating large samples at synchrotron sources.

Speaker: Dominik John (Hereon (Helmholtz-Zentrum Hereon))

Figure 1.png

Figure 2.png

229 Imaging and Real-Time Data Processing at the Terabyte Scale

The gradual shift to 4th-generation synchrotron sources has been boosting data production rates that nowadays easily exceed 1-10 TB of produced raw image data per day. This has not only created a big data bottleneck in terms of data storage, management, processing, and visualization, but also requires a revised approach in utilizing state-of-the-art data processing techniques. In the recent past, several open-source efforts have been established, ranging from reconstruction algorithms [1-3], volume data analysis and visualization tools [4] to storage and metadata handling frameworks [5]. However, these can be considered “silo” solutions that not necessarily interface with each other smoothly. Moreover, in many cases the transition from single proof-of-concept-based code toward making software available to a wider (big) imaging community is still far from being established.

Both at TOMCAT and at LNLS, we have independently been developing and utilizing state-of-the art processing tools. As one of the biggest data producers of the Swiss Light Source, the TOMCAT beamline has guaranteed smooth user operation for over a decade now thanks to an efficient data pipeline [6]. More recently, real-time reconstruction capabilities [7] and TB-sized volume analysis tools [8] have been added to ease the data analysis challenge. At LNLS, we have pioneered novel GPU-enhanced tomographic reconstruction algorithms [9], including phase recovery filters in both directions [10]. Furthermore, we have advanced in-memory processing capabilities, allowing visualization with optimized and fast rendering using the Nvidia/Index API [11] as well as on-the-fly segmentation [12], both using the RDMA protocol. In summary, all these strategies represent cornerstones that can now be integrated into a generalized platform as well as conventional graphical interfaces that will further allow the development of user-defined plugins and facilitate rapid exchange.

In the present work, we devise and describe a general architectural concept for data flow in typical tomographic imaging experiments, which involves both the underlying application stack with its “gluing” components as well as a full operating model in a standardized HPC environment. We present and discuss the feasibility of tomography scans with processing times of several seconds up to a minute, for volumes of several hundreds of GBs. To achieve stable operation, we leverage recent developments in IT architectural frameworks and apply industry-standard best practices for modularity, virtualization, and CI/CD. We show how our architecture drastically improves the user experience. Finally, we discuss different implementations of GPU/CPU communication and present benchmarks of reconstruction and visualization tools using different hardware.

References:

[1] D. Gürsoy, F. De Carlo, X. Xiao et al., J. of Synchrotron Radiat 21, 1188, 2014.
[2] V. Nikitin, J. Synchrotron Radiat 30, 179, 2023.
[3] W. van Aarle et al., Opt. Express 24(22), 25129, 2016.
[4] A. Aboulhassan et al., J. Imaging 8(7), 187, 2022.
[5] Moore, J., Allan, C., Besson et al., Nat. Methods 18(12), 1496, 2021.
[6] F. Marone, A. Studer, H. Billich et al., Adv. Struct. Chem. Imaging. 3(1), 1, 2017.
[7] J.-W. Buurlage et al., Sci. Rep. 9(1), 18379, 2019.
[8] A. Miettinen, I. V. Oikonomidis, A. Bonnin et al., Bioinformatics 35(24), 5290, 2019.
[9] E. X. Miqueles et al., PPSC 2020. https://doi.org/10.1137/1.9781611976137.3
[10] E. X. Miqueles, P. Guerrero, Results Appl. Math. 6, 100088, 2020.
[11] T. V. Spina et al., JACoW 2021 , https://doi.org/10.18429/JACoW-ICALEPCS2021-FRBL05
[12] A. Pinto et al., Synchrotron Radiat. News 35(4), 36, 2022.

Speaker: Goran Lovric (Swiss Light Source)

230 A 3D Graph Neural Network-Based Approach to 3D Structure Analysis of XAS

X-ray Absorption Spectroscopy (XAS) is an instrumental technique for elucidating the atomic-scale three-dimensional local structure of materials. Within XAS, the X-ray Absorption Near Edge Structure (XANES) region is particularly significant, as it provides insight into the three-dimensional structural characteristics. However, extracting quantitative three-dimensional structural information from XANES data necessitates a profound comprehension and precise assessment of structural nuances, often requiring the synthesis of multiple structural parameters—a feat that can be challenging to accomplish. Here, we develop Physics-Informed Graph Neural Network models capable of computing XANES spectra directly from inputted 3D structures. We improve the efficiency of the model based on the physical meaning of XAS. Initially, we focus on geometric features, specifically bond lengths, angles, and the dihedral angles between the absorbing atom and its surrounding atoms, which play a pivotal role in determining the fine structures observed within the spectrum. Consequently, these are deemed the most efficacious geometric parameters to be incorporated into our model. Furthermore, a judiciously selected feature function is implemented to augment the predictive efficacy of the model. Secondly, we examine the definition of a graph tailored for XAS analysis. In previous 3D GNN model, the typical approach adopts a uniform distance cutoff to define neighboring atoms around a central atom. But for XANES which primarily investigates the local environment surrounding the absorber atom, the topological significance of the graph edges associated with the absorber becomes critical. To address this, we introduce a customized graph extraction methodology in our XAS3Dabs model, which selectively focuses on the immediate vicinity of the absorber atom.

Speaker: Haifeng Zhao (Institute of high energy of physics, Chinese academy of science)

Mikrosymposium 4/3: New Detector Developments: MS4/3

231 Detector Development for High Repetition Rate FELs and 4th Generation SR Sources

Dedicated detector developments for X-ray photon science have significantly contributed to the scientific success of new photon sources. With the development of 4th generation storage rings and high repetition rate FELs new, more performant, X-ray cameras are needed. I will present the ongoing detector developments at DESY for PETRA IV. TEMPUS is a system based on the new TimePix-4 chip. CoRDIA is an integrating system with adaptive gain, running at 150k fps. I will also present and plans for a new system for the European XFEL.

Speaker: Heinz Graafsma (DESY)

232 The CITIUS detector

At the latest synchrotron radiation facilities featuring multi-bend achromat (MBA) storage rings, the current state-of-the-art photon-counting detectors are challenged by the intense X-rays impinging upon the detector. The pileup due to the slow in-pixel counting circuitries typically limits the count rate to around a few Mcps/pixel [1] and reduced further for several bunch modes [2]. To extend the dynamic range, we developed the CITIUS detector (Charge Integration Type Imaging Unit with high-Speed extended-dynamic-range) [3]. The novel integrating-type pixel structure, with a size of 72.6 $\mu$m square, enables detection of 945 Mcps/pixel at 10 keV, corresponding to 18 Tcps/cm$^2$, which is higher than any other detectors reported so far. It should be pointed out that the CITIUS integrating-type pixels sustain this dynamic range for any bunch modes. The extremely high dynamic range of CITIUS represents a significant advancement for coherent imaging applications such as Bragg CDI [4] and ptychography [5-7]. It also shows potential in high-speed and high-accuracy single crystal X-ray diffraction [8].

Unlike in-pixel photon counting pixels, which have non-sensitive areas at the corners of the pixels [9], the integrating-type pixels of CITIUS are free from such efficiency drops, thereby delivering higher uniformity and achieving a 100% fill factor. The CITIUS detector is equipped with a silicon sensor that is 650 micrometers thick, significantly thicker than typical photon-counting detectors. This combination of a 100% fill factor and a thicker sensor makes CITIUS especially useful for applications demanding higher sensitivity, such as quasielastic scattering spectroscopy [10]. In this case, an FPGA-based compression technique developed for CITIUS [11] was employed to compress data of 35 PBytes from week-long experiments with a compression ratio exceeding 1000.

Despite its high dynamic range, CITIUS maintains a low noise floor, allowing for the detection of single photons and even their photon energies. Recently, spectro-imaging with CITIUS has demonstrated higher data quality in laboratory-based computed tomography [12] and in fluorescence-yield XAFS. By operating in a multi-sampling mode, the noise floor can be further lowered to resolve photon energies with a resolution of 250 eV FWHM.

Moreover, the CITIUS detector, with 580 kpixels operating in an XFEL mode, has provided new scientific data at SACLA. A 20.2 Mpixel system has recently been installed at a SACLA beamline, and this talk will briefly report on its commissioning status [13].

References
[1] P. Denes, B. Schmitt, J. Synchrotron Rad., 21 (2014) 1006.
[2] Y. Imai, to be presented at this conferece. Y. Imai and T. Hatsui, J. Synchrotron Rad., 31 (2024) 295.
[3] SPring-8 II Conceptual Design Report, RIKEN SPring-8 Center, 2014
[4] M. Grimes, et.al, J. Applied Crystallography, 56 (2023) 1032.
[5] Y. Takahashi, et.al., J. Synch. Rad., 30 (2023) 989.
[6] J. Deng, et.al., J. Synchrotron Rad., 30 (2023) 859.
[7] K. Ozaki, to be presented at this conference.
[8] Y. Imai, to be presented at this conference.
[9] Ch. Broennimann, et.al., J. Synchrotron Rad. 13 (2006) 120.
[10] M. Saito, et.al., Phys. Rev. Lett., 132, (2024) Art. Num. 256901.
[11] H. Nishino et.al., Nucl. Inst. Meth. Phys. Res., A1057 (2023) Art. Num. 168710.
[12] V. Di Trapani et.al, presented at iWoRiD 2024.
[13] H. Nishino, to be presented at this conference.

Speaker: Takaki Hatsui (RIKEN SPring-8 Center)

233 Progress in the Development of Multi-Element Monolithic Germanium Detectors in LEAPS-INNOV Project: Insights from Detector Performance Simulation

The XAFS-DET (Work Package 2) of the European LEAPS-INNOV project has undertaken an ambitious research and development program for a new generation of multi-element monolithic germanium detectors best suited for synchrotron applications XAFS-DET: A new high throughout X-ray spectroscopy detector system developed for synchrotron applications. The detector has a new age sensor design for charge-sharing event rejection, an optimized mechanic design based on thermal simulations, and a new full electronics. In this regard, we have conducted simulations of the detector response by integrating the versatile Geant4 toolkit and Solid State Detector (SSD) packages Simulation of semiconductor detectors in 3D with SolidStateDetectors.jl. With this code, we can estimate the induced waveforms in adjacent pixels based on event positioning, aiming to reject the multi-site and pile-up events using a Digital Pulse Processor (DPP) DANTE Digital Pulse Processor for XRF and XAS experiments, for an active refinement of the detector performance Development of multi-element monolithic germanium detectors for X-ray detection at synchrotron facilities.

Our findings shed light on the performance characteristics of Germanium detector prototypes using a known soil sample in environmental science (EnviroMAT), which allowed us to build a background model and to predict the expected signal at a given Photon flux. The simulation chain was calibrated by experimental data taken with a commercial high-purity germanium (HPGe) detector in the SAMBA beamline of Synchrotron SOLEIL and is illustrated in Fig 1

Fig 1: Full simulation chain: (i) Geometry of big pixel configuration of Ge detector produced using SSD simulation packages; (ii) simulated waveform for an event collected in a single contact using the hit information from Geant4 ; (iii) Comparison of simulations with the data acquired with commercial HPGe detector using EnviroMAT soil sample.

Speaker: Nishu Goyal (soleil synchrotron)

Fig1.pdf

234 UFERI – Hybrid Photon-Counting Pixel Detector Prototype for Diffraction Experiments at Synchrotrons

In preparation of the upcoming upgrade of the SOLEIL synchrotron to a fourth-generation facility [1], the local detector group and the ASIC design group from AGH University, Krakow, are developing a new single photon-counting hybrid pixel detector prototype called UFERI (Ultra-Fast Energy Resolved Imager [2]). It is dedicated to pseudo-Laue diffraction applications in intense, pink beams at photon energies between 5 to 30 keV. With its three thresholds, UFERI is able to discriminate several energy levels and its short dead time ensures a high count rate capability up to 7 Mcnts/s/pix. To maintain a low noise in high count rate operation, a capacitor discharge technique [3] is implemented on-chip. Additionally, three independent gates for the three discriminators combined with a short gating time allow for ultra-fast pump-probe-probe measurements.
In this contribution, a description of the ASIC’s architecture as well as the main results of the characterisation are presented. We show the energy calibrations, threshold dispersions and gain spread, as well as the count rate and timing performance of UFERI.

[1] J. Susini, J. M. Cassagne, B. Gagey, A. Nadji, A. Taleb, A. Thompson and J. Daillant, “A brief introduction to the Synchrotron SOLEIL and its upgrade programme”, The European Physical Journal Plus 2024 139:1, vol. 139, no. 1, pp. 1-8, 1 2024.
[2] F. Orsini, A. Dawiec, B. Kanoute, P. Grybos, R. Kleczek, P. Kmon and P. Otfinowski, “Ultra-Fast Energy Resolved Imager for `Pseudo' Laue diffraction experiments at synchrotron facilities”, Journal of Instrumentation, vol. 19, no. 02, p. C02055, 2 2024.
[3] R. Kleczek, P. Kmon, P. Maj, R. Szczygiel, M. Zoladz and P. Grybos, “Single Photon Counting Readout IC with 44 e-rms ENC and 5.5 e-rms Offset Spread with Charge Sensitive Amplifier Active Feedback Discharge”, IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 70, no. 5, pp. 1882-1892, 5 2023

Speaker: Marie Andrä (Synchrotron SOLEIL)

abstract_SRI_uferi_MarieAndrae.pdf

235 Pixel Detectors with Front-End Suitable for Amplitude Spectroscopy, Frameless Readout, and Per-Pixel Configuration

Design of Pixel Detectors with analog front-end (AFE) that is suitable for amplitude spectroscopy, true event-driven readout, selective, i.e., per pixel, configuration and built-in testability is presented. The target is a pixelated sensors readout application specific integrated circuit (ASIC) based on front-end and backend technologies recently pursued by BNL, which include, for the front-end part, a charge amplifier operationally configured with active feedback network of the resistive-nature, employing the self-cascoded field-effect transistor topology for leakage current compensation and realizing trans-linear pole-zero cancellation for precise, cascadable input charge signal multiplication, and for the back-end part: 1) event-driven readout system, yielding non-priority access to on-a-chip readout resources, thanks to application of Seitz’s arbiters both in the ‘read request’ part and ‘access acknowledgment’ path of the readout access arbitration architecture, 2) expansion of the event-driven system to asymmetric half-duplex communication, allowing per pixel, selective programming of configuration bits, with minimal addition of precious circuit resource, and, 3) testability features seamlessly incorporated into the readout and configuration framework.
The back-end concept is formalized and constrained in hardware description language for automated implementation of virtually arbitrary pixel fabric of a sensors readout ASIC’s using the industry standard CAD/EDA tools. The concept forms a holistic conceptual framework called Configuration-Testability-Readout (CTR).
The AFE circuit network realizes continuous–time processing of input charge signals. The charge amplifier is followed by a shaping filter implementable within an area–constrained footprint of a pixel in finely pixelated sensors, catering to a broad spectrum of X–ray photon energies, spanning 2 keV even two orders of magnitude up. The design aims at a spectroscopic–grade energy resolution, achieving it, in the case of coverage of the energy band spanning more than one decade, through splitting the signal processing into high– and low–sensitivity paths. The same front-end is suited for photon counting, whereas using it in combination with the event driven readout is believed to yield the maximum achievable throughputs.
An illustration, showcasing the back-end design components of ASICs utilized for reading out pixel sensors, accompanied by depictions of the manufactured ASICs and the outcomes of testing of the event-driven readout is given in Fig. 1. There were fabricated small scale prototypes: with square 100 um^2-pitch or hexagonal 150 um^2-pitch pixels (including charge sharing compensation) as well as test structures aiming at benchmarking lossless readout and ability to automatically synchronize with a synchronous data acquisition.

Speaker: Grzegorz Deptuch (Brookhaven National Laboratory)

sri_2024_deptuch.png

236 Chromium Compensated Gallium Arsenide Sensor Evaluation Using Photon Counting Readout Electronics

Gallium arsenide is extensively studied for about seven decades as an excellent material for
semiconductor lasers, LEDs, and microwave electronics. GaAs has noticeable advantages over silicon
and Cd(Zn)Te for radiation detectors. Particularly GaAs has higher electron mobility compared to Si
and Cd(Zn)Te; higher average atomic number compared to Si; and lower probability and energy of the
fluorescence photons compared to the Cd(Zn)Te [1]. These advantages result in a fast charge
collection, good absorption efficiency up to 50 keV and a better uniformity compared to Cd(Zn)Te.
Applications for the GaAs are foreseen in medical, mammography, small animal imaging, electron
microscopy, synchrotrons, XFELs and non-destructive testing of composite materials. (see PDF for complete abstract please)

Speaker: Juha Kalliopuska (Advafab Oy)

SRI2024_abstract_GaAs_evaluation.pdf

237 Spectroscopic Hard X-ray Imaging at MHz Frame Rates

The High Energy X-ray Imaging Technology (HEXITEC) camera system was developed by the Science & Technology Facilities Council (STFC) in the late 2000’s with the aim of delivering fully spectroscopic (colour) X-ray imaging at energies 2 – 200 keV. The original system has a pixel pitch of 250$\mu$m, 80×80 pixels, each with an energy resolution of ~ 800eV running at 10kHz. To correct for sensor effects such as charge sharing, the system is run at <10% occupancy which limits it’s use to photon fluxes of ~ 10$^{4}$ ph s$^{-1}$ mm$^{-2}$. The original camera has been used in a broad range or fields, from battery$^{[1]}$ and materials science$^{[2]}$ at synchrotrons to medical imaging$^{[3]}$, these flux restrictions have limited its applications in some areas, like colour CT. Prompted by a new generation of diffraction limited storage rings, STFC have developed a new generation of the technology that can operate at fluxes in excess of 10$^{6}$ ph s$^{-1}$ mm$^{-2}$ without compromising spectroscopic performance.

The HEXITEC-MHz ASIC runs at a continuous 1 million frames per second which, when coupled to high-flux-capable CdZnTe material, delivers per pixel spectroscopy for hard X-rays in the range 2 – 300 keV with a resolution of < 1keV for polychromatic sources up to fluxes of 2×10$^{6}$ ph s$^{-1}$ mm$^{-2}$ $^{[4]}$. The capabilities of the camera system enable the use of techniques such as full colour X-ray CT for dynamic systems on time scales of <1s at synchrotron facilities and beyond. The integrating architecture also means that, where a monochromatic source is in use, the system can be used up to fluxes of 2×10$^{8}$ ph s$^{-1}$ mm$^{-2}$ (assuming 30keV X-rays).

A summary of recent testing using lab-based sources and the Diamond Light Source will be presented. These include measurements with monochromatic 20keV X-rays that have confirmed the excellent per-pixel energy resolution of the system of 0.8keV for HF-CdZnTe sensors and 0.6keV for p-type Si sensors at a flux of 10$^{6}$ ph s$^{-1}$ mm$^{-2}$ $^{[5]}$.

[1] C. Leung et al., https://doi.org/10.1016/j.mtener.2022.101224
[2] S. Feng et al., https://doi.org/10.1557/mrs.2020.270
[3] S. Mandot et al., https://doi.org/10.1109/TMI.2023.3348791
[4] M. Veale et al., https://doi.org/10.1088/1748-0221/18/07/P07048
[5] B. Cline et al., https://doi.org/10.1016/j.nima.2023.168718

Speaker: Matthew Veale (STFC Rutherford Appleton Laboratory)

Veale_HEXITEC_MHz_SRI_24.pptx

Veale_HMHz_SRI_2024.pdf

Mikrosymposium 7/4: Imaging and Cohrerence Applications: MS7/4

238 An Upcoming Novel Coherent Diffractive Imaging Beamline at National Synchrotron Light Source II

The application of techniques designed to capitalize on the high source brightness at current generation storage ring facilities continues to produce unique insights into the structure and dynamics of materials. At NSLS-II, we are nearing the completion of a new beamline designed to provide tunable x-ray illumination—in both size and coherence fraction—sample environments, and experimental geometries. The design considerations, beamline optical system simulations, end-station provisions, and progress toward its completion in 2025 will be presented here.

The CDI beamline’s source will be provided by an 18-mm-period in-vacuum undulator and the 3 GeV electrons from NSLS-II. The undulator will feature a variable taper, delivering an increased x-ray bandwidth of at least 5% RMS at 10 keV. The optical system will use two bendable x-ray mirrors in conjunction with two fixed-figure mirrors to provide a sample illumination that allows variable coherence properties in a “zoomable” x-ray focal spot of about 1 to 10 microns in lateral size. Thus, the optical design provides a unique opportunity to tailor beam properties to the needs of each experiment. All aspects of the design were modelled and informed by simulations with the Synchrotron Radiation Workshop tool.

The final optics will provide a very long working distance of approx. 1.5 m and the sample-to-detector distance will be variable from 0.5 m to 10 m. Two area detectors will be independently positionable, allowing for simultaneous measurements in either or both of the forward-scattering and a Bragg-reflection geometry. The angular coverage of the detector system varies from approx. 70(V) x 120(H) to 11(V) x 120(H) degrees as a function of sample-to-detector distance.

The CDI beamline will present an exciting capability for routine, high-stability coherent imaging measurements and a uniquely-capable test-bed for the development and refinement of future imaging methods. We are currently on-track to commission this beamline in Summer 2025.

Speaker: Garth Williams (Brookhaven National Laboratory)

239 New CDI methodologies for higher efficiency, resolution and quality at the Coherent Scattering beamline in HEPS

Speaker: Liang Zhou (HEPS, IHEP, CAS, CHINA)

240 xLEAP: A new resources for bio-microprobe imaging

Synchrotron x-ray microscopy methods are valuable tools for quantitative imaging of micronutrients and metals in a wide range of biological systems and at multiple length scales [1,2]. The Cornell High Energy Synchrotron Source (CHESS) is uniquely positioned to build a dedicated x-ray facility for the study of biological systems, especially plants, leveraging existing infrastructure and expertise in the School of Integrative Plant Sciences (SIPS) at Cornell and its many affiliated research centers.

In February 2024, the U.S. National Science Foundation announced an award that will support construction of a new x-ray beamline customized for research in plant and soil sciences at CHESS. The new beamline project, X-rays for Life, Environmental, Agricultural, and Plant sciences (XLEAP) will specialize in x-ray fluorescence microscopy, enabling quantitative imaging of micronutrients in biological systems at length scales ranging from whole tissues to cells. The science priorities for XLEAP, driven by workshops and conferences in 2020-2023, include (1) fundamental mechanisms in plant sciences, such as micronutrient uptake, transport, and storage; (2) how plants respond to external stimuli such as nanoparticles, microplastics, bacteria, and fungi, as well as climate and environmental factors; (3) mechanisms of elemental transport and cycling at the root-soil interface and in soil degradation processes; and (4) mechanisms of elemental uptake and cycling in aquatic flora, seaweeds, algae, and other organisms.

We will discuss the planned x-ray capabilities of the XLEAP beamline, which include x-ray fluorescence microscopy (2D mapping, 3D computed tomography, and 3D confocal imaging), x-ray absorption spectroscopy, and x-ray diffraction, with tunable spatial resolution from >100 µm to <1 µm, energies ranging from 5-70 keV, and high-flux or high-energy-resolution modes. XLEAP will also offer users complementary optical microscopy, plant growth, and sample preparation facilities, as well as the potential for in-situ x-ray measurements with a custom plant growth environment directly on the beamline. We will illustrate the planned experimental modes and describe new possibilities for flexible access to accommodate experiments with longer time scales.

The CHESS XLEAP beamline will be constructed over the next four years with user operations planned to begin in 2028. During construction, graduate students and faculty from the University of Texas at El Paso will collaborate with CHESS staff and Cornell faculty on pilot experiments that develop future user capabilities and workflows for XLEAP. The community is invited to shape the user experience at XLEAP by participating in workshops and designing pilot experiments during this construction phase.

[1] Kopittke, P.M., T. Punshon, D.J. Paterson, R.V. Tappero, P. Wang, F.P.C. Blamey, A. van der Ent, and E. Lombi, Synchrotron-Based X-Ray Fluorescence Microscopy as a Technique for Imaging of Elements in Plants. Plant Physiology, 2018. 178(2): p. 507-523 DOI: 10.1104/pp.18.00759

[2] Smieska, L.M., M.L. Guerinot, K.E. Olson Hoal, M.C. Reid, and O.K. Vatamaniuk, Synchrotron Science for Sustainability: Life Cycle of Metals in the Environment. Metallomics, 2023. 15(8): mfad041. DOI: 10.1093/mtomcs/mfad041

This project is made possible by a US National Science Foundation Midscale Research Infrastructure 1 award (USNSF-2330043).

Speaker: Louisa Smieska (Cornell High Energy Synchrotron Source)

241 Development of adaptive X-ray microscopy based on ultraprecise deformable mirrors

Hard X-ray microscopy is very promising for nondestructive and high-spatial-resolution observation of the internal structure of a sample. However, the spatial resolution of microscopes remains unsatisfactory owing to the fabrication error in the objective lens. This problem is becoming more serious, especially as the spatial resolution decreases.

To overcome the problem and achieve ultrahigh resolution, we proposed and developed a monolithic deformable mirror based on a lithium niobite single crystal (LNDM) and a novel adaptive imaging system based on LNDM, which enables high-precision, high-stability, and high-spatial-frequency-controlled deformation (Fig. 1) [1]. Unlike lead zirconate titanate (PZT), which is often used for deformable mirrors, the surface of the single-crystal piezoelectric material can be atomically smoothed by superpolishing; thus, it can function as an actuator and a reflective surface for X-rays. This enables a simple structure consisting only of an LN substrate and electrodes, which would contribute to improving deformation accuracy. In addition, because single-crystal LN is a single-domain piezoelectric material, it can be expected to deform with high precision without hysteresis or drift.

A prototype LNDM was designed and fabricated. An X-ray interferometer confirmed that wavefront compensation using the LNDM could be performed with a shape accuracy of 0.67 nm under high stability (0.17 nm over 7 h) and hysteresis-free deformation control (Fig. 1 right). An adaptive X-ray microscope based on advanced Kirkpatrick-Baez mirror optics including the LNDM demonstrated that the wavefront aberration caused by mirror fabrication error was successfully corrected, resulting in an improvement in X-ray image quality (Fig. 2) [1].

[1] T. Inoue and S. Matsuyama et al., Monolithic deformable mirror based on lithium niobate single crystal for high-resolution X-ray adaptive microscopy, Optica, accepted.

Fig. 1 Developed monolithic deformable mirror (left) and result of shape correction (right).

Fig. 2 X-ray images obtained using the adaptive X-ray microscope before and after the shape correction.

Speaker: Satoshi Matsuyama (Nagoya University)

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242 LAMINO-II at the IMAGE Beamline of the KIT Light Source: A New Instrument for Systematic In Situ and Operando Studies and Hierarchical Imaging for Materials and Life Sciences

With LAMINO-II and UFO-II, two new experimental stations have recently become available at the superconducting wiggler beamline IMAGE at the KIT Light Source, dedicated for 2D/3D/4D full-field hard X-ray imaging for materials and life sciences. UFO-II focusses on serial micro-tomography, namely systematic high-throughput 3D imaging of large sample series with minimum user interaction. LAMINO-II significantly advances the opportunities of synchrotron radiation computed laminography (CL), in particular for systematic 4D in situ and operando studies as well as for hierarchical imaging. Here CL has unique capabilities for high-resolution 3D imaging of flat samples exceeding the field of view, therefore avoiding any sample dissection [1, 2].

The dedicated, 8-ton LAMINO-II allows a tilted (20°-45°) rotation of flat samples up to 250x250x40mm³ in size and 4kg of maximum weight with <1 µm error motion, which represents a considerable engineering challenge. It facilitates up to 80cm wave field propagation to a bank of two selectable detectors and it can be equipped with further imaging optics. In addition, a cable drag is available, altogether enabling LAMINO-II to handle large samples or sample environments like dedicated mechanical tensile/compression testing devices for systematic 3D in situ imaging with micrometer resolution. Here the 3D access to flat and laterally extended sample geometries allows unique in situ studies of highly application-relevant stress states, e.g., with low stress triaxiality or load path changes [3, 4]. By enabling large lateral sample scanning (75x75 mm²), LAMINO-II allows 3D screening of large regions as well as hierarchical 3D imaging by zooming in on selected regions of interest guided by on-the-fly data processing [5].

We report main instrumental features of the new LAMINO-II station and illustrate its methodical capabilities by first experimental results, particularly (1) of unprecedented screening and hierarchical imaging of compression fossils within the context of several centimeter-sized specimens, and (2) of 3D in situ damage analysis of plate-like devices, altogether demonstrating the unique application potential from in situ testing, via operando failure analysis up to paleontology.

Figure caption
a) Scheme of the new LAMINO-II station; b) In situ laminography for materials testing [3], c) Hierarchical 3D laminography of a compression fossil.

References
[1] Helfen et al., Appl. Phys. Lett. 86, 071915 (2005).
[2] Helfen et al., Rev. Sci. Instrum. 82, 063702 (2011).
[3] Kong et al., Acta Mater. 231, 117842 (2022).
[4] Buljac et al., Mech. Mater. 178, 104558 (2023).
[5] Hurst et al., Sci. Rep. 13, 1055 (2023).

Speaker: Tilo Baumbach (Karlsruhe Institute of Technology (KIT), Institute for Photon Science and Synchrotron Radiation (IPS); Karlsruhe Institute of Technology (KIT), Laboratory for Applications of Synchrotron Radiation (LAS))

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243 Rethinking Coherent Diffraction Instruments for High-Brightness Sources

Over the past two decades, exceptional progress has been made providing coherent x-ray beams at both high-brightness synchrotron sources and x-ray free electron lasers (XFEL). The availability of these coherent x-rays has led to a surge in instruments that exploit x-ray coherence for either x-ray photon correlation spectroscopy (XPCS) or coherent diffraction imaging (CDI). A key to these techniques has been to resolve, or at least nearly resolve, the speckles associated with the scattering from structural disorder, either static or dynamic, that exists in condensed matter systems. Since the resolution of x-ray detectors, particularly at high frame rate, is limited by pixel size, the needed angular resolution has been achieved by moving the detector much farther (often 10-20 meters) from the source.

Conventionally, the momentum transfer, and hence the length scales studied, has been adjusted by changing the 2θ value of the scattered x-rays from forward scattering. This approach requires moving large detectors over significant physical distances, a process that is both slow and that uses a large amount of floor space. At both synchrotrons and XFELs, space is limited, and a much more efficient system would be achieved if we could change the direction of the incoming x-rays instead of the scattered x-rays, thus leaving the detector fixed.

We have been exploring an instrument design that can efficiently provide a long sample-detector distance while maintaining the ability to rapidly set momentum transfer by inserting crystals with different order in the incident beam, thus changing in incident direction instead of moving the detector.

We will present the results of numerical simulations of a conceptual instrument including wave front propagation of both synchrotron and XFEL beams through the instrument, analysis of speckle size and contrast for as well as the signal-to-noise ratio for several classes of samples using the optimized beam and sample parameters.

This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. Work by H.L. was supported by U.S. Department of Energy, Office of Science under DOE (BES) Awards DE-SC0022222.

Speaker: Paul Fuoss (SLAC National Accelerator Laboratory)

244 A Monolithic X-ray Achromatic Lens

Chromatic aberration has been a long-standing challenge for lens-based X-ray microscopy, significantly limiting image resolution or reducing the usable portion of the photon flux since the field's inception in the 1970s. However, recent advancements have led to the development of the first achromatic and apochromatic lenses for X-rays, both exhibiting a constant focal length over wide photon energy ranges. Regrettably, the potential performance in this first demonstration has been limited by the challenges associated with accurate alignment of the single elements that compose the doublet. In this study, we introduce the development of a monolithic X-ray achromat, in which the two elements composing the achromatic double are produced in a single substrate, thus accurately aligned during the fabrication steps (Figure 1).
As in the original X-ray achromatic lens [1], the optical device is composed of a Fresnel zone plate (FZP and compound refractive lens (CRL). The FZP was fabricated with high-resolution electron beam lithography and gold electroplating on a 250-nm thick silicon nitride membrane. In the monolithic approach, we employed two-photon polymerization to print the CRL directly on the FZP substrate frame, a method that ensures an alignment accuracy in the order of 100 nm. The 3D printing design of the CRL has been modified integrating enhanced structural reinforcements to strengthen its robustness as well as enabling the fabrication of taller structures. In particular, a robust arch-like support structure for the lens is also adopted to improve the mechanical stability in an intense X-ray beam for a high aspect ratio CRL structure. This approach reduces the alignment degree of freedom during an experiment from 6 to 2, thereby dramatically enhancing imaging quality and data collection efficiency. A comparison of STXM images of the same sample of the monolithic design and the previous doublet design is shown in Figure 2. High efficiency and quality fluorescence imaging across a broad energy range for multiple elements, as well as transmission X-ray microscopy (TXM) imaging with micro-bot samples have successfully demonstrated the advantages of using a monolithic achromat. [2]
Our monolithic X-ray achromat overcomes the technical limitations of using individual elements, thus establishing a better paradigm for implementing such X-ray lenses in X-ray microscopy setups. This breakthrough is paving the way for a more generalized use of X-ray achromatic, thus pushing further the applications of X-ray microscopy for academic and industrial research.
[1] A. Kubec, M.-C. Zdora, U. T. Sanli, A. Diaz, J. Vila-Comamala, and C. David, An achromatic X-ray lens, Nat. Commun., vol. 13, no. 1, p. 1305 (2022), doi: 10.1038/s41467-022-28902-8.
[2] P. Qi et al., Monolithic achromatic X-ray lens, in preparation.

Speaker: Peng Qi (Paul Scherrer Institut)

ABSTRACT A monolithic x-ray achromat lens_PengQi.pdf

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Mikrosymposium 8/1: New Opportunities for High Pressure Research: MS8/1

245 Nuclear Resonance Scattering at ESRF with submicron spatial resolution

The nuclear resonant scattering based on the Mössbauer effect in iron has proven to be an important spectroscopic method to address the most advanced scientific issues of physics and chemistry, as well as of material sciences, and is indispensable in Earth and planetary sciences. Synchrotron Mössbauer Source (SMS) spectroscopy¹ is the ultimate method to characterize the electronic states of iron atoms, allowing for an accurate determination of the oxidation and spin states, phase analysis, magnetic structure, and phase transitions in iron-bearing alloys and compounds. In turn, Nuclear Inelastic Scattering (NIS) is a powerful tool for studying lattice dynamics that provides access to vibrational and thermodynamic properties².
The ESRF-EBS upgrade and related refurbishment of the nuclear resonance beamline ID14 resulted in a significant reduction of the beamsize for nuclear resonance scattering methods. The beamline is now equipped with the submicron precision positioning system compatible with the beamsize of 0.6 x 0.6 μm² provided through the specially designed short-focal distance Kirkpatrick-Baez mirrors³.
The extreme spatial resolution will serve studies employing extreme-high-pressure conditions with implications to geoscience, magnetism, and solid-state chemistry but will also aid the investigation of ultra-small systems like stardust or diamond inclusions. Moreover, this allows for studies of macroscopic samples with sub-micron resolution, enabling for example the mapping of magnetic memory of meteorites or element-partitioning analysis.
In this contribution, I would like to report the recent advances in nuclear resonance methods employing sub-micron spatial resolution. In particular, I will discuss the first examples of experiments at extreme pressure-temperature conditions, studies of micrometeorites, utilization of Young double-waveguide nano-interferometer, and investigation of metamagnetic transition for energy-efficient magnetic devices.
References
1. Potapkin, V. et al. The 57Fe synchrotron Mössbauer source at the ESRF. J. Synchrotron Radiat. 19, 559–569 (2012).
2. Chumakov, A. I. & Sturhahn, W. Experimental aspects of inelastic nuclear resonance scattering. Hyperfine Interact. 123–124, 781–808 (1999).
3. Kupenko, I. et al. Nuclear resonance techniques for high-pressure research: example of the ID18 beamline of the European Synchrotron Radiation Facility. High Press. Res. 1–27 (2024). doi:10.1080/08957959.2024.2371023

Speaker: Ilya Kupenko (ESRF)

2024-07-03-Kupenko_SRI.pdf

246 MHz X-ray diffraction in diamond anvil cells at the HED Instrument

The advent of the first X-ray free-electron lasers (XFELs), FLASH in 2004 and LCLS in 2009, may prove to be the most profound development since the invention of the laser and, equally, the synchrotron. Sharp improvements in a number of laser parameters, most notably intensity and pulse duration, support this expectation. This brings scientific dreams within reach. Indeed, the unprecedented opportunities and expectations have triggered considerable research activities worldwide.

In my talk, I will give an overview of the experimental application of the European XFEL, in particular to explit the unique hard x-ray capabilities together with the MHz pulse train. I will highlight MHz x-ray diffraction in diamond anvil cells for materials in extreme conditions science and laboratory astrophysics.

Since May 2019, the High Energy Density Science (HED) instrument at the European X-ray Free-Electron Laser Facility in Schenefeld, Germany, allows international users to investigate a wide range of materials and systems at extreme conditions [1]. European XFEL and the HIBEF user consortium [2] form a joint group of more than 40 people for HED research, development and user operation.
To drive a sample from ambient conditions to extreme excitations, a variety of high energy drivers are available. In particular, we have three separate optical laser systems for warm- to hot-dense-matter creation, dynamic compression and laser-plasma interaction in electron-relativistic regime. These drivers allow studying various phase space parameters with time-resolution down to 10 fs, pressures into the TPa regime, and electric field strength up to 1021 W/cm, both at surfaces and in the bulk.

The unique HED instrument allows to study these systems with precise ultrafast x-ray probes including spectroscopy, x-ray diffraction, small- and wide-angle scattering as well as phase contrast imaging methods. It is fully tuneable in the photon energy range from 5 to 25 keV at different bandwidths, can be focused to a variety of diameters.

The talk will go into further detail about the diamond anvil cell platform [3] at the HED instrument, its instrumentation and capabilities. Followed by this, I will highlight examples of MHz diffraction, and also MHz emission spectroscopy and phase contrast imaging.

[1] U. Zastrau, et al., J. Synchrotron Rad. (2021). 28, 1393-1416
[2] www.hibef.de
[3] Liermann et al., J. Synchrotron Rad. (2021). 28, 688-706

Speaker: Ulf Zastrau (Eur.XFEL (European XFEL))

247 Extreme condition research at ESRF

Here we present the new experimental stations devoted to the studies of matter under extreme conditions at the X-ray diffraction beamline ID15b and the X-ray absorption beamlines BM23 and ID24-DCM that were recently refurbished within the ESRF – Extremely Brilliant Source (EBS) upgrade program. In comparison with the stations before the EBS upgrade, they exhibit outstanding performances in terms of sample positioning capabilities, acceptance of multi-detection systems and complex sample environments. In addition, significant improvements regarding the photon flux and focusing capabilities down to the submicron size have been achieved. The XAS stations are now coupled with the new ESRF double crystal monochromators that exhibit an exceptional beam position and energy stability and that permit quick micro-EXAFS measurements down to one EXAFS/second, and hyperspectral EXAFS mapping. In this contribution, we discuss the choices regarding the sample and detector stages and illustrate the potential of the new setups for extreme conditions studies based on selected preliminary results.

Speaker: Angelika Rosa (ESRF, the European Synchrotron)

248 In Situ Energy-Dispersive XRD and Imaging in the Large Volume Press at P61B

The Aster-15 LVP can routinely generate high pressure (ca. 35 GPa) and temperature (ca. 3000 K) environments on samples for investigations using energy-dispersive X-ray diffraction (ED-XRD) and radiography in the high-energy range 30 – 160 KeV at the Wiggler beamline station P61B. Specialised assemblies may generate even higher pressures. The station provides two highly positional Ge-detectors for XRD acquisition at user-defined pre-calibrated diffraction angles (3° < 2θ < 10°), including vertical positioning for cubic compression (3° < 2θ < 20°) with one detector. During sample deformation (p < 15 GPa), stresses from lattice microstrains can be measured with both detectors at 2θ = 5° or greater (at 0° and 90° azimuthal positions). This setup is enhanced using X-ray transparent cBN and sintered-diamond anvils. A movable beamstop is available to reduce background scattering. Furthermore, we offer additional in situ techniques, such as 1) acoustic emissions detection with 6 sensors, combined with deformation to study brittle processes in samples, and 2) ultrasonic wave speed measurements using a LiNbO3 transducer and a signal amplification system to study the physical properties of materials at pressures over 20 GPa in assemblies as small as 10 mm. Imaging experiments, such as falling sphere viscosimetry, are enhanced with an extremely bright scintillator: GAGG:Ce on the x-ray microscope (up to 1 kHz acquisitions). Finally, a suite of data processing software can be found on the beamline website. In summary, proposals can be submitted to P61B for beam time (normal access) and for time without X-rays (fast access). We will present details on the current status and development of P61B at PETRA III, as well as information about a future LVP beamline at PETRA IV.

Speaker: Robert Farla (FS-PETRA-D (FS-PET-D Fachgruppe P61 (Wiggler Bl.)))

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249 The New Multi-Anvil End-Stations of SSRF

Two end-stations based on large volume presses (LVP) have been built at SSRF, equipped with 200-ton and 2000-ton large volume presses respectively. These stations officially open to users in January 2024. The 2000-ton press adopts a dual-module design, supporting both Kawai and DDIA modules, and has achieved a pressure of 40GPa. The 200-ton press uses DDIA module. Both experimental stations can conduct energy dispersive diffraction, XRD, and high-resolution imaging experiments. In addition, they can also carry out high-temperature experiments with a maximum temperature exceeding 2100K. The establishment of the LVP experimental stations at SSRF represents a new opportunity for international research on high-temperature and high-pressure experiments based on large volume presses.

Speaker: Ke Yang (shanghai advanced research institute)

250 Pressure-Induced Microstructural Changes of Au and Pt Nanomaterials at High Pressure

The microstructure of nanoparticles, which is closely related to their size-tailored mechanical properties, has driven intensive investigations in the past decades [1-5]. It is recognized that the mechanical properties of nanoparticles may differ significantly from those of their bulk counterparts [2,3]. However, despite extensive studies, the origin of different mechanical behaviours as a function of their particle size remains elusive due to inconsistent results. Even for the well-studied gold, the equation of state (EOS) varies considerably (Fig. 1a). Both gold and platinum are common pressure markers in high-pressure experiments due to their low strength, moderate compressibility, chemical inertness, and good X-ray scattering power, and therefore have been thoroughly studied theoretically and experimentally, e.g. Refs [6-10]. Accurate EOS of Au and Pt is also very important for ultrahigh-pressure experiments in the mutli-megabar region.
In this conference, we report our recent progress in high-energy x-ray focusing[11] and the pressure-induced microstructural changes of nanocrystalline Au and Pt particles at high pressure by X-ray total scattering techniques(Fig. 1b) under quasi-hydrostatic conditions [11,12]. It is shown that the microstructure of n-Au is nearly a single-grain/domain at ambient conditions, but undergoes substantial pressure-induced reduction in grain size (Fig. 1c). The results indicate that the nature of the internal microstructure in n-Au is associated with the observed EOS difference from bulk Au at high pressure [12]. The internal microstructure inside nanoparticle plays a critical role for the macro-mechanical properties of n-Au and n-Pt particles.

Figure 1. (a) EOS of n-Au compared to previously reported data; (b) (Upper panel) Pair distribution function, g(r); (c) (Lower panel) Evolution of the average size of the Au nanodomains.
References:
[1] Q. F. Gu, G. Krauss, W. Steurer, F. Gramm, and A. Cervellino, Physical Review Letters 100, 045502 (2008).
[2] B. Gilbert, F. Huang, H. Zhang, G. A. Waychunas, and J. F. Banfield, Science 305, 651 (2004).
[3] S. H. Tolbert and A. P. Alivisatos, Science 265, 373 (1994).
[4] T. S. Duffy, G. Shen, J. Shu, H.-K. Mao, R. J. Hemley, and A. K. Singh, Journal of Applied Physics 86, 6729 (1999).
[5] B. Chen, K. Lutker, J. Lei, J. Yan, S. Yang, and H.-k. Mao, Proceedings of the National Academy of Sciences 111, 3350 (2014).
[6] T. Tsuchiya, Journal of Geophysical Research: Solid Earth 108, 2462 (2003).
[7] P. Souvatzis, A. Delin, and O. Eriksson, Physical Review B 73, 054110 (2006).
[8] Y. Fei, A. Ricolleau, M. Frank, K. Mibe, G. Shen, and V. Prakapenka, Proceedings of the National Academy of Sciences 104, 9182 (2007).
[9] K. Takemura and A. Dewaele, Physical Review B 78, 104119 (2008).
[10] S. M. Dorfman, V. B. Prakapenka, Y. Meng, and T. S. Duffy, Journal of Geophysical Research: Solid Earth 117, B08210 (2012).
[11] X. Hong, L. Ehm, Z. Zhong, S. Ghose, T. S. Duffy, and D. J. Weidner, Scientific Reports 6, 21434 (2016).
[12] X. Hong, T. S. Duffy, L. Ehm, and D. J. Weidner, Journal of Physics: Condensed Matter 27, 485303 (2015).
010203040505456586062646668701020304005101502040600100200300m-HEX diff. PDF (run-1) PDF (run-2) Vinet fit Bulk-Au (Dorfman et al) 30 nm Au (Gu et al) 50-100 nm Au (Martin et al)Volume (Å3)Pressure (GPa)EOS of Au(a)(b)G(r)r (Å)Pressure (GPa)Quenched7139202 run-1 run-2 EOS Pressure (GPa)QuenchedApparent size (
Å)(c)

Speaker: Xinguo Hong (Center for High Pressure Science and Technology Advanced Research, Beijing)

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251 The Extreme Condition Beamline, EMA, at Sirius

The research exploring the limits of thermodynamical parameters, such as pressure, temperature, and magnetic field, is a fast-growing and fascinating discipline of science and technology that unravel many truths and facts of nature, which are not possible in ambient conditions. However, improving the quality of the experimental data obtained at extreme thermodynamical remains challenging. To understand the implication of such huge contraction, small focused X-ray beams, smaller than 1 micrometer, is essential to allow in-situ investigations of the crystalline and electronic structure of materials under high pressure. The Extreme condition Methods of Analysis beamline (EMA), of the new Brazilian synchrotron light source (SIRIUS), was designed to overcome this challenge by having both ~0.5x1 µm$^2$ focused beam size with high photon flux ($10^{13}$ photons/s @ 10 keV) and ~100x100 nm$^2$ focused beam size (with ~$10^{11}$ photons/s @ 10 keV), both with well-defined gaussian beam shape, which will allow the realization of X-ray absorption (XAS), X-ray diffraction (XRD), coherent diffraction image (CDI) and X-ray Raman experiments at extreme pressure.

Here, we present the optical parameters and experimental conditions made available at the EMA beamline, along with the recent technical and scientific commissioning results obtained at the beamline. In this study, we demonstrate how EMA uses its bright focused beam to perform diverse experiments combined with state-of-the-art extreme thermodynamic conditions instrumentation, such as high-pressure capabilities at the Mbar regime to low and high temperatures (as low as 300 mK, as high as 8000 K), and high magnetic fields (up to 11T), to explore yet unreached points of the phase diagram. Finally, we also describe the new experimental station, under development, which is optimized for nanometer focusing.

Speaker: Narcizo Souza Neto (Brazilian Synchrotron Light Source (LNLS/Sirius))

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13:00 Lunch Break

Mikrosymposium 12/3: Time Resolved Techniques: MS12/3

252 ID29 SMX - A universal Time-Resolved Crystallography Beamline

The European Synchrotron facility – ESRF has recently been upgraded to Extremely Brilliant Source (EBS) [1]. The new storage ring with an extremely low horizontal emittance and > 30 times more brilliant than 3rd generation sources allows to expand the scope of synchrotron radiation for Macromolecular X-ray crystallography (MX). After EBS upgrade, the highly focused and intense X-ray beam bridges the gap between any 3rd generation synchrotron and X-ray free electron lasers (XFELs), enabling data collection from micron-sized biomolecular crystals. This enabled development of a dedicated time-resolved serial crystallography (TR-SSX) beamline. Thus, old ID29, a formerly experimental phasing microfocus MX beamline [3], was entirely re-built to World’s first leading beamline towards µs-time-resolved serial crystallography. The beamline produces 10-µs pulsed X-ray beam with a continuous flux of ~1015 photons/sec and equipped with multi-layer monochromator resulting in 1% bandwidth. ID29 – TR-SSX beamline enables to explore the uncharted < 100 µs exposures domain between 3rd generation source and XFEL. Two chopper systems mechanically produce the pulsed X-ray beam synchronized with the reference frequency of the storage ring. ID29 is equipped with KB-mirrors to produce 1 µm X-ray beam, state-of-the-art MD3up-SSX diffractometer, a nanosecond tunable high-repetition laser, and Jungfrau 4M detector, enabling data acquisition rate of 925 Hz.
In the talk, the new ID29 beamline together with developments in sample-delivery, data acquisition system, time-resolved setup will be introduced and opportunities of various SSX data collection at the ID29 will be highlighted.

Reference:
[1] Raimondi, et al., Nature comm. physics., 2023
[2] Chapman et al., Nature, 2011
[3] de Sanctis D., et al., J. Synch. Rad., 2012

Speaker: Shibom Basu (European Molecular Biology Laboratory - EMBL Grenoble)

BASU_SRI2024_v2.docx

253 The new time-compensated monochromator beamline FL23 at FLASH

FLASH, the soft X-ray free-electron laser (FEL) in Hamburg provides high-brilliance ultrashort femtosecond pulses at MHz repetition rate for user experiments. For high resolution spectroscopic and dynamical studies in various research fields a narrow FEL energy bandwidth and ultrashort pulses are a prerequisite. While single grating monochromators provide high-energy resolution they introduce a pulse-front tilt which effectively elongates the longitudinal pulse profile, thus decreasing the time resolution. In order to preserve a short pulse duration and still monochromatize the FEL radiation, the new pulse-length preserving monochromator beamline FL23 at FLASH2 uses a double-grating design. A first grating disperses the radiation and an intermediate slit reduces the spectral bandwidth, a second grating operating in compensating configuration turns back the pulse front tilt, thereby preserving the ultrashort photon pulses.

The open port beamline covers the spectral range between 1.3 nm and 20 nm with a spectral resolving power of approximately 1500 [1]. The beamline can also be operated in a single grating configuration in order to maximize the transmission at the high energy end. A bendable Kirkpatrick-Baez mirror system – similar to the one used at the FL24 beamline at FLASH – provides flexible microfocusing at the experiment. A femtosecond optical laser synchronized to the FEL is provided for pump-probe experiments. The beamline concept and design has been developed using ray tracing simulations and confirmed by wavefront propagation simulations [2]. The commissioning phase was successfully completed and since 2024 the beamline is in FLASH user operation.

Here, results from the technical commissioning of the beamline and its components as well as of first user experiments will be presented.

Speaker: Guenter Brenner (FS-FLASH-B (FLASH Photon Beamlines and Optics))

254 Event-Guided Temporally Super-Resolved Synchrotron X-ray Imaging

Synchrotron-based X-ray micro-computed tomography is the reference technique for a number of studies investigating fundamental properties and functions of materials and organisms. However, the increased use of imaging technologies is becoming more and more challenging, as high-speed dynamical imaging experiments either produce exorbitant amounts of data or remain limited in temporal resolution. Recently, event cameras have been introduced as an alternative approach to conventional frame-based cameras, in the sense that they detect per-pixel brightness changes asynchronously and generate a stream of events encoding the triggering time, location, and polarity of each pixel [1]. This adaptive and asynchronous feature offers several advantages, including high temporal resolution (on the order of µs) and high dynamic range (up to 140dB), making event cameras particularly suitable for applications requiring fast response times and/or operation in dynamic environments. Although event-based vision has recently gained popularity in various applications, its realization in X-ray imaging remains unexplored.

At the TOMCAT beamline of the Swiss Light Source (Paul Scherrer Institut, Villigen, Switzerland), we have developed a new inline dual-camera setup which incorporates a high-speed frame-based CMOS detector [2], and a bio-inspired neuromorphic event camera (Prophesee, Metavision Evaluation Kit 4, EVK) [3]. Both cameras were combined with magnifying visible light optics to achieve a pixel size of 1.1 µm and were synchronized with an external 1Mhz TTL signal by utilizing the PandABox (Position and Acquisition Box). Based on this setup, we present a novel event-guided approach for temporal super-resolution of the sampled frame data. As a first example, we characterize the system by imaging a live sandclock in radiographic mode and present all necessary post-processing steps for achieving greater than five-fold super-resolution. Our work marks the first exploration of the potential of event cameras in dynamic X-ray imaging. We report its current performance and limitations and discuss the potential to reduce the data generation rate, facilitating more efficient data transmission, real-time processing, and visualization in future time-resolved synchrotron X-ray imaging experiments.

References:
[1]​G. Gallego et al., “Event-based Vision: A Survey,” IEEE Trans. Pattern Anal. Mach. Intell., vol. 44, no. 1, pp. 154–180, Jan. 2022, doi: 10.1109/TPAMI.2020.3008413.
[2]​R. Mokso et al., “GigaFRoST: the gigabit fast readout system for tomography,” J Synchrotron Rad, vol. 24, no. 6, pp. 1250–1259, Nov. 2017, doi: 10.1107/S1600577517013522.
[3]​“Event Camera Evaluation Kit 4 HD IMX636 Prophesee-Sony,” PROPHESEE. Available: https://www.prophesee.ai/event-camera-evk4/

Speaker: Hongjian Wang (ETHz/PSI)

Figure-setup.JPG

255 Time-Resolved Experiments Using Unique Pulse Structure at the SPB/SFX Scientific Instrument of the European XFEL

The Single Particles, Clusters, and Biomolecules and the Serial Femtosecond Crystallography (SPB/SFX) instrument at the European XFEL (EuXFEL) has been in operation since 2017 [1]. This instrument is focused on coherent diffractive imaging (CDI) and serial femtosecond crystallography (SFX) methods. Intense (mJ), ultrashort (fs) and MHz X-ray FEL pulses at the European XFEL also allow the collection of damage-free data with fast data acquisition. The combined experiment with optical lasers gives the opportunity for ultrafast pump-probe measurements [2]-[3]. EuXFEL operates in the so-called ‘burst mode’ with a burst duration of 600 s at a repetition rate of 10 Hz. Each burst can have a single pulse or a train of pulses with an intra-burst repetition rate of up to 4.5 MHz. This unique pulse structure opened MHz data rate measurement and also microsecond time-resolution experiments [4]-[5]. Recently, MHz X-ray microscopy was established and opened for user program [6]-[7]. We will introduce laser-induced fragmentation of droplet experiment using unique pulse structure and discuss on microsecond measurements at the SPB/SFX instrument of the EuXFEL.
[1] A. P. Mancuso et al.:” The Single Particles, Clusters and Biomolecules and Serial Femtosecond Crystallography instrument of the European XFEL: initial installation," J. Synchrotron Radiat. 26, 660–676 (2019)
[2] S. Pandey et al.: "Time-resolved serial femtosecond crystallography at the European XFEL," Nature Methods 17, 73–78 (2020).
[3] J. Koliyadu et al.:“ Pump–probe capabilities at the SPB/SFX instrument of the European XFEL“, J Synchrotron Rad 29, 1273–1283 (2022).
[4] P. Vagovič et al.: "Megahertz x-ray microscopy at x-ray free-electron laser and synchrotron sources," Optica, OPTICA 6, 1106–1109 (2019).
[5] M. Kuramochi et al.: "Direct observation of 890 ns dynamics of carbon black and polybutadiene in rubber materials using diffracted x-ray blinking," Applied Physics Letters 123, 101601-1-9 (2023).
[6] F. Reuter et al.: "Laser-induced, single droplet fragmentation dynamics revealed through megahertz x-ray microscopy," Physics of Fluids 35, 113323-1-9 (2023).
[7] H. Soyama et al.: "Revealing the origins of vortex cavitation in a Venturi tube by high speed X-ray imaging," Ultrasonics Sonochemistry 101, 106715-1-16 (2023).

Speaker: Tokushi Sato (Eur.XFEL (European XFEL))

256 Two-Dimensional Quasi-Elastic Scattering Imaging Technique To Visualize Nanosecond Atomic Dynamics

The dynamics study of microscopic structures provides information about the microscopic states, which is often the most fundamental origin of some material properties such as viscoelasticity. Inelastic/quasi-elastic scattering techniques allow us to study the microscopic dynamics of the selected structures of interest in the wavenumber vector space. Mössbauer gamma rays generated by synchrotron radiation (SR) provide the directed and highly monochromatic beam that can be used for quasi-elastic scattering experiments. Time-domain interferometry is the SR-based quasi-elastic scattering technique that uses the Mössbauer gamma rays to study the microscopic dynamics in the time domain between 10 ns and several 100 μs [1-3]. The energy domain counterpart has also been demonstrated [4-6]. However, the low measurement efficiency has prevented its widespread application. In this presentation, we introduce a novel SR-based energy-domain quasi-elastic scattering technique using the multi-line Mössbauer gamma rays emitted/analyzed by the 57Fe2O3 monochromator/analyzer [7]. The resulting resolution function of the multi-line system shows the multiple energy widths, allowing to effectively cover relatively wide time scales from 100 ps to sub 100 ns. In addition, the introduction of the two-dimensional X-ray detector CITIUS greatly improved the measurement efficiency and enabled two-dimensional quasi-elastic scattering imaging [7,8]. We introduce the principle of the new system and how the new system is useful for the study of various condensed matter systems.

References
[1] A. Q. R. Baron, et al., Phys. Rev. Lett. 79, 2823 (1997).
[2] M. Saito, et al., Sci. Rep. 7, 12558 (2017).
[3] M. Saito, et al., Phys. Rev. Lett. 109, 115705 (2012).
[4] D. C. Champeney, and F. W. D. Woodhams, J. Phys. B. 1 (1968).
[5] R. Masuda, et al., J. Appl. Phys. 48, 120221 (2009).
[6] T. Mitsui, et al., J. Phys. Soc. Jpn. 91, 064001 (2022).
[7] M. Saito et.al., submitted.
[8] T. Hatsui et.al., in preparation.

Speaker: Makina Saito

257 Time-Resolved Ambient Pressure Photoelectron Spectroscopy for Studying Mechanisms of Catalytic Reactions under Operando Conditions

Recently, a new time-resolved Ambient Pressure X-ray Photoelectron Spectroscopy (APXPS) method based on chemical perturbations has been developed for studying dynamic processes with microsecond time resolution. The method uses the rapid change in the gas pressure/composition as a perturbation that drives the system away from equilibrium [1,2]. In the experiment, a sharp and strong gradient in chemical potential is created by modulating the gas composition over the catalyst via a fast valve. Such gas pulse has internal pressure in the mbar range and a rising edge of a few hundred microseconds. A time-sensitive delayline detector is synchronized with the valve operation to measure X-ray photoemission spectra with nano- to microsecond time resolution. We will present several experiments characterizing the setup’s performance, including the CO oxidation reaction over Pt (111) to demonstrate the capability of the setup to correlate the gas phase composition with that of the surface during the transient supply of CO gas into an O2 stream (Figure 1) [3]. These experiments demonstrate that under CO pressure modulation conditions, the system remains active (i.e. producing CO2) at temperatures below the CO lift-off temperature, i.e. under the flow conditions. We will also demonstrate that the chemisorbed oxygen is observed during the catalytic cycle after the Pt(111) surface is saturated with the oxide. This points out a much higher activity of the O_chemisorbed towards CO oxidation than O_oxide, resolving the ongoing debate about the role of the Platnum surface oxide in the reaction.

Figure 1. Time-resolved APXPS measured during pulsing CO into a constant flow of O2 onto Pt(111) at 330 C. (Left) O 1s gas phase and surface time-resolved spectral maps. (Right) individual spectra measured at time delays indicated by the dashed arrows.

[1] J. Knudsen et al. Nat Commun 12, 6117 (2021). doi:10.1038/s41467-021-26372-y
[2] A. Shavorskiy et al. ACS APPLIED MATERIALS & INTERFACES 13, 47629 (2021). doi: 10.1021/acsami.1c13590
[3] C. Eads et al. in preparation

Speaker: Andrey Shavorskiy (MAX IV Laboratory)

tr-apxps.jpg

258 XPCS in Bunch Mode: XPCS-echo and Wide Timescale Measurements

With the emergence of 4th generation synchrotrons, X-ray Photon Correlation Spectroscopy (XPCS) has improved both in terms of the available coherent photon flux and speckle contrast [Chevremont2024]. Together with fast photon counting pixel array detectors, this technique has become more attractive for the investigation of a broad range of systems [Narayanan2023]. However, one of the main limitations of XPCS measurements is the sample degradation by the X-ray beam and resulting beam-induced dynamics [Chushkin2022]. Yet another bottleneck when performing XPCS at a high frame rate for a long time is the time and memory needed to process the data, which scale quadratically with the number of frames.

To address these issues, a novel acquisition scheme has been developed at the TRUSAXS
Instrument (beamline ID02), ESRF. This new scheme has been termed as “time resolved” or “bunch mode” XPCS. It involves acquiring frames at the highest frame rate according to the lowest lag time to be measured only when needed and thus exposure of the sample to the beam is minimized. Bunches of frames are acquired, spaced by variable dead time where the fast beam shutter remains closed and the sample unexposed to X-ray beam. The autocorrelation functions are still calculated by performing the correlation between all the frames, and reconstructing the two-time correlation function (TTCF) before averaging.

In this work, the application of the bunch mode XPCS is demonstrated on samples (colloidal gels formed by short-range attraction between particles) whose correlation functions span over several orders of magnitude in lag time. Another interesting application is for XPCS-echo, where the acquisition is synchronized with an oscillatory motion of the sample imposed by a rheometer [Pham2004]. In this experiment, the detector frames are acquired on each oscillation period and echoes in the autocorrelation function [g2(q,t)] appear each time the sample returns to the initial position. The envelope of echoes measured corresponds to the decay of the autocorrelation function due to the intrinsic dynamics in the sample. For fully reversible motion, the envelope strictly corresponds to the autocorrelation function of the sample at rest. On the other hand, an acceleration of the decorrelation occurs when the sample yields with increasing amplitude of deformation. The XPCS-echo then provides an elegant way to measure the intrinsic dynamics within the sample, discriminating the Doppler shifts caused by the shear.

Figure: Measurements of XPCS-echo and normal autocorrelation functions of a dense colloidal suspension of PMMA particles (size ~ 800 nm) in cis-decalin subjected to oscillatory shear of varying amplitudes at a frequency of 10 Hz.

W. Chevremont, T. Zinn & T. Narayanan, J. Synchrotron Rad., 31 (2024) 65. T. Narayanan, W. Chevremont & T. Zinn, J. Appl. Cryst., 56 (2023) 939.
Y. Chushkin, A. Gulotta, F. Roosen-Runge, A. Pal, A. Stradner & P. Schurtenberger, Phys. Rev. Lett., 129 (2022) 238001.
K. N. Pham, S. U. Egelhaaf, A. Moussaı¨d, & P. N. Pusey, Rev. Sci. Instrum., 75 (2004) 2419.

Speaker: William Chèvremont (ESRF)

Mikrosymposium 14/1: Miscellaneous Topics: MS14/1

259 Aspects of Sustainability of Accelerator Driven Light Sources

In this talk I will present several initiatives taken by European synchrotron sources towards a more sustainable operation in line with the recommendations of ESFRI report on energy and supply challenges of research infrastructures.
Examples will cover the optimization and reduction in electric power consumption. I will in particular discuss the use of permanent magnets in storage rings as well as the use of photovoltaic panels to reduce the dependence on external suppliers.
I will also describe efforts towards a more sustainable use of water and cryogenic fluids.
More generally, some figures will be given regarding the carbon footprint of research infrastructures.
A quantitative discussion of the gains that can be achieved following best practices will be given.

Speaker: Jean Daillant (Synchrotron SOLEIL)

260 The Design and Progress of the Data and Computing System for HEPS

The 14 beamlines for the phase I of High Energy Photon Source(HEPS) will produces more than 300PB/year raw data. Efficiently storing, analyzing, and sharing this huge amount of data presents a significant challenge for HEPS.

HEPS Computing and Communication System(HEPSCC), also called HEPS Computing Center, is an essential work group responsible for the IT R&D and services for the facility, including IT infrastructure, network, computing, analysis software, data preservation and management etc. Aimed at addressing the significant challenge of large data volume, HEPSCC has designed and established a network and computing system, making great progress over the past two years.

For the IT infrastructure, A deliciated and high-standard machine room, with about 900㎡ floor space for more than 120 high-density racks in total has been ready for production since this August. The design of the network utilizes RoCE technology and a spine-leaf architecture. The data center network’s bandwidth can support speeds of up to 100Gb/s, fully meeting the demands of high- speed data exchange. To meet the requirements of data analysis scenarios for HEPS, a computing architecture is designed and deployed in three types, including Openstack, Kubernetes, and Slurm. Openstack integrates the virtual cloud desktop protocol to provide users with remote desktop access services, and supports users to use browsers to access windows/Linux desktop, running commercial visualization data analysis software. Kubernetes manages container clusters, and starts multiple methodological container images according to user analysis requirements. Slurm is used to support HPC computing services and meet users' offline data analysis needs.

Additionally, HEPSCC designed and developed two softwares for the data management and analysis, DOMAS and Daisy. DOMAS (Data Organization, Management and Accessing Software stack), which is aimed for automating the organization, transfer, storage, distribution and sharing of the scientific data for HEPS experiments, provides the features and functions for metadata catalogue, metadata ingestor, data transfer, data web portal. Daisy (Data Analysis Integrated Software System) is a data analysis software framework with a highly modular C++/Python architecture. Some online data analysis algorithms developed by HEPS beamlines have been integrated into Daisy successfully most of which were validated at the beamlines of BSRF (Beijing Synchrotron Radiation Facility) for the real-time data processing. Other data analysis algorithms/software will be continuously integrated to the framework in the future.

In 2021, A testbed was set up at beamline 3W1 of BSRF, which is a running synchrotron radiation facility and provides the technology R&D and test platforms for HEPS. The 3W1 beamline, which is dedicated to test high-throughput instruments for HEPS. It is an ideal candidate to set up the testbed where we can deploy the system and verify the functions and the whole process of data acquisition, data processing, data transfer, data storage and data access.
The integration and the verification of the whole system at 3W1 beamline were finished and achieved great success. It strongly proved the rationality of the design scheme and the feasibility of the technologies. After the optimization and upgrade of the functionality, in July 2022, all the sub-systems of HEPSCC were deployed at 4W1B, which is a running beamline at BSRF, can provide full process service for beamline users.

Speaker: Hao Hu (Institute of High Energy of Physics)

261 Probing Dopant and Defect Energy Levels in Next Generation Nitride Phosphors

My talk will focus on nitride semiconductors used for lighting applications. I will give an overview of our group’s soft X-ray spectroscopy at the endstation for inelastic soft X-ray scattering at the REIXS beamline at CLS. We use X-ray absorption (XAS), X-ray emission (XES), Resonant inelastic X-ray scattering (RIXS) and X-ray excited optical luminescence (XEOL) to probe the electronic structure of new nitride semiconductors used in lighting applications. Our density functional theory calculations model the measured spectra and allow to extract more detailed information from the systems studied.
The examples I will discuss include Eu-doped nitrides where we are able to experimentally directly determine the energetic separation of the Eu 5d state and the conduction band of the host lattice. The 5d energies are critical to the color and efficiency of LED phosphors.
We also directly observe conduction to valence band and 4f to valence band transitions in X-ray excited optical luminescence spectra of a series of cutting-edge phosphors [1-3].
In a series of new nitride semiconductors, intraband states caused by defects are monitored by luminescence and the measurements are compared to our density functional theory calculations.
Finally, I will present a new nitride, GeP2N4, which is structurally distinct from all other known MP2N4 systems (M = Be, Ca, Sr, Ba, Mn, Cd) due to the presence of unique Ge2+ lone pairs [4-5].

References
[1] Z. Yang et al., Advanced Materials 35, 2301837 (2023)
[2] T.M. Tolhurst et al., Chem. Mat. 29, 7976-7983 (2017)
[3] M.R. Amin et al., Adv. Opt. Mat. 8, 2000504 (2020)
[4] T. de Boer et al., J. Mat. Chem. A 11, 6198-6204 (2023)
[5] S.J. Ambach et al., Angewandte Chemie (Int. Ed.) 135, e202215393 (1 to 5) (2023)

Speaker: Alexander Moewes (University of Saskatchewan)

262 A Generic Rolling Access for Users at PETRA III \& Future PETRA IV

Major synchrotron radiation facilities typically operate under classical access models (CAMs), which are reliable but lack agility and responsiveness for urgent, collaborative, and long-term projects. In response to user concerns, adaptations such as rapid access proposals, block allocation group proposals (BAG), and long-term proposals (LTP) have been implemented alongside the CAMs. However, bi- or tri-annual proposal calls continue to be conducted. Furthermore, a select number of facilities have adopted multiple proposal calls or a rolling access system exclusively for highly standardized, and fully automated beamlines, such as molecular or protein crystallography, and small angle X-ray scattering beamlines.

Recognizing the need for change, PETRA III and future PETRA IV are introducing the rolling procedure with a single access scheme, which could be implemented in any generic beamlines. The new access model aims to replace CAMs while meeting modern demands and preserving CAMs’ strengths. A testing phase on five beamlines at PETRA III has been implemented through this rolling procedure, eliminating the bi-annual call and various access schemes (kept valid for all other beamlines). The streamlined process allows users to submit proposals at any time without any deadline and strongly reduces waiting time between proposal submission and experiment execution. The latter is adaptable during the process and will still allow longer time if requested by the users. This rolling procedure allows for scheduling throughout the year, which is advantageous specially for commercial users, and users with urgent needs. Additionally, a key feature of this procedure is the opportunity to distribute approved shifts into multiple beamtimes if multiple beamtime access is requested during submission.

The implementation of this rolling procedure could pose challenges in maintaining transparency in the rolling review and scheduling process. Unlike the Classical Access Models (CAMs), where proposals are evaluated together bi-annually and ranked for scheduling, the rolling review lacks comparison with other proposals. To address the challenges, a new review procedure has been devised, which involves a combination of independently evaluating each proposal and holding regular meetings within the review panel. A preliminary model simulation of the new scheduling scheme indicates that top-ranked proposals can be scheduled immediately, with an average wait time of three months between proposal submission and actual beamtime. The simulation indicates that unscheduled shifts would only range from 3-6%, manageable through commissioning and testing. In the practical testing phase, the process will be refined based on the results obtained and feedback received, aiming to overcome potential challenges associated with implementing a rolling procedure for large-scale user facilities.

Speakers: Arka Bikash Dey (FS-PETRA-BO (Beamline Optics Simulation)), Oliver Seeck (FS-PETRA-D (PETRA-D))

Abstract_Rolling_Access_SRI.docx

263 A Miniature Split-Pair Coil Sample Environment at the Materials Imaging and Dynamics Instrument of the European XFEL

The MID instrument at the European XFEL uses hard X-ray FEL beam to study material dynamics on solid-state systems [1]. We introduce a miniature pulsed magnetic field setup and a sample cryostat that can be installed at the MID interaction chamber to allow an applied magnetic field up to 15 T and sample temperature control from 10 K to 300 K on fixed solid targets. The split-pair coils of the magnet are suited to studying single-crystal diffraction and magnetic scattering in the horizontal scattering plane where tuning magnetic field and temperature can be used to establish a thermodynamic state or to probe a phase transition. The duration of the magnetic field pulse is ~1 ms and chosen to overlap with the 0.55 ms long FEL pulse-train to make best use of the FEL beam. A useful aspect of the setup is operation without the need for X-ray windows. We describe the integration of the setup at the MID instrument with the technical challenges that were faced. Commissioning of the setup was completed and has demonstrated the setup performance for user beamtimes at the MID instrument.

A recent upgrade of the miniature pulsed magnetic field setup has been to allow X-ray Photon Correlation Spectroscopy (XPCS) and Coherent X-ray Diffraction Imaging (CXDI) on micrometer-sized samples. This requires stability in sample position also on the order of the sample size and minimization of sample vibrations introduced from the rapidly changing magnetic field pulse. We use laser interferometry to characterize the setup stability and performance.

[1] A. Madsen et al. ”Materials Imaging and Dynamics (MID) instrument at the European X-ray Free-Electron Laser Facility” J. Synchrotron Rad. 28, 637-649 (2021)

Speaker: James Moore (Eur.XFEL (European XFEL))

264 Advancements in X-ray Optics for High-Resolution Imaging: Bridging Commercial Innovation and Research Collaboration

XRnanotech, born from the collaborative spirit of the Paul Scherrer Institut, is a vanguard in the evolution of X-ray optics. Our foundation in advanced nanolithography techniques has enabled us to craft optical elements with an unparalleled level of precision, reaching into the single-digit nanometer territory. We harness a diverse array of sophisticated methodologies, including electron-beam nanolithography, two-photon polymerization, and direct laser writing, to forge diffractive optical elements that are pivotal for high-resolution X-ray imaging across premier research facilities worldwide.

Our endeavor transcends the commercial sphere, as we engage in fruitful collaborations with leading research institutions like the Paul Scherrer Institut. These partnerships are the bedrock of our mission to continuously push the boundaries of diffractive optics, especially within the exacting high-energy X-ray spectra. Our journey also explores the frontiers of refractive optical elements and reflective optics, navigating their inherent challenges to unveil groundbreaking developments.

The essence of diffractive optics lies in their precision in controlling the optical wavefront, facilitating the creation of complex functionalities. Our contributions span an extensive array of applications, from sophisticated beam-shaping optics to spiral zone plates and achromatic optical elements. By leveraging innovative fabrication techniques, novel materials, and creative designs, we aim not only to advance the commercial landscape of nanotechnology in X-ray optics but also to catalyze research and development in this dynamic field.

This presentation will highlight XRnanotech's recent strides in the fabrication of X-ray optical elements, focusing on their enhanced resolution, efficiency, and optical functionality. Our vision is to ignite a dialogue with fellow researchers and industry partners, inspiring collaborative endeavors, joint grant proposals, and innovative projects that strive to elevate the capabilities of high-resolution imaging. Join us in exploring the future of X-ray optics, where commercial ingenuity meets collaborative research excellence.

Speaker: Adam Kubec (XRnanotech GmbH)

265 Novel Passive Resonant Structures for Precision Assembly of Synchrotron X-ray Optics

Many optics at synchrotron and free electron laser facilities need to be cooled to dissipate the heat imparted by the intense photon beams. For indirectly-cooled optics, distortion of the surface caused by excessive clamping forces during assembly, typically utilising Belleville washers with an inaccuracy of approximately 20%, can lead to significant distortion and defocussing of the X-ray beam [1,2]. To address this issue, it is necessary to monitor the effects of assembly and subsequent life cycle on the clamping forces applied to the crystal. In this paper, we present experimental verification of a non-contact approach to the monitoring of clamping forces utilising novel, additively manufactured passive resonant structures that can remain in-situ throughout an optics life cycle [3]. Two stainless steel 316L passive structures, based on a doubly curved hyperbolic paraboloid (z = xy), were incorporated as part of the first crystal assembly for the I20 monochromator at Diamond Light Source, as shown in Figure 1(a). Experimental work demonstrated the ability to monitor the clamping forces applied to the crystal throughout the assembly process by measuring the resonance of the passive structures. This monitoring process was also applied after a cryogenic thermal cycle. Laser doppler vibrometry revealed frequency shifts in the passive structures around 20-60 Hz after cryogenic cooling (see Figure 1(b)), which is indicative of a change in clamping force of up to approximately 25 %. These results were correlated with Fizeau interferometer measurements of the optical surface. The results also reveal a greater uniformity of the optical surface of the crystal for the novel approach when compared with conventional assembly, as depicted in Figure 1(c), noting the gap in the centre dur to heat exchangers. The novel approach outlined in this paper has the potential to significantly improve the accuracy to which beamline optics are assembled and, as a result, their subsequent performance on the beamline.
Figure 1 – Experimental validation of novel passive resonant structures, with (a) experimental set-up, (b) example frequency response shift before and after cooling and (c) example Fizeau interferometer measurements of the optical surface.
References
[1] E. V. Bainbridge, J. D. Griffiths, J. Clunan and P. Docker, Journal of Synchroton Radiation, vol. 29, 2022.
[2] D. Cocco, G. Sostero and M. Zangrando, SPIE 4145, Advances in X-Ray Optics, San Diego, 2001.
[3] E. V. Bainbridge, J. D. Griffiths, H. Patel, J. Clunan and P. Docker, Journal of Synchrotron Radiation, vol. 30, pp. 1143-1148, 2023.

Speakers: Eleanor Victoria Bainbridge, Jonathan Griffiths (University of Lincoln)

figure_ellie 2.tif

Mikrosymposium 3/4: Data, Automation and the Use of AI: MS3/4

266 AI/ML-Driven Alignement, Stabilization and Control of Beamline Optics at the Advanced Photon Source Upgrade

In experiments conducted at 4th-generation synchrotron radiation and free electron laser (FEL) beamlines, the primary challenge for X-ray optical elements is to achieve and maintain focused X-ray beams with high intensity, near-perfect wavefront quality, and exceptional stability. Additionally, in diffraction-limited light sources that produce coherent photons, preserving well-controlled wavefronts is crucial, since the deterioration of the wavefront can adversely affect imaging [1] and coherent X-ray scattering experiments [2-3]. As a result, precision manufacturing of X-ray optics is essential, adhering closely to an ideal mathematical shape. These optics should possess the capability to align and focus the beam based on various sample and experiment requirements, automatically and consistently. Furthermore, they should be able to provide real-time correction in response to wavefront deformations [4].
In the last few years, extensive studies and experiments have been carried out at the Advanced Photon Source (APS) at Argonne National Laboratory with the purpose to engineer automatic optics control systems, supported by Artificial Intelligence (AI) technologies and advanced, real-time wavefront sensing techniques, to pursue near-perfect wavefront control at the future beamlines of the upgraded APS-U synchrotron. We developed and successfully tested at the 28-ID IDEA beamline of the APS a neural-network (NN) machine learning (ML) model to control a bimorph adaptive mirror to achieve and preserve aberration-free coherent X-ray wavefronts. The NN is trained to manage the time-dependent relation between the hardware setup and the wavefront properties at the experiments [5]. In parallel, we employed Bayesian optimization (BO) with Gaussian processes (GPs) to automatically align and stabilize the focusing optical systems of hard X-ray synchrotron radiation beamlines and experimentally tested at the 28-ID IDEA beamline, providing effective steering of the optical assembly [6]. These prototypical systems have been improved and engineered to manage the optics of the featured beamlines of the new APS-U synchrotron, through extensive studies of AI-driven technologies and the use of real-time, full-field, single-shot wavefront sensing downstream of the focus [7].
References
[1] M. Yabashi et al., J. Synchrotron Rad. 21, 976 (2014).
[2] A. Rack et al. Nucl. Instrum. Methods Phys. Res. A 710, 101 (2013).
[3] A. Zozulya et al., J. Phys.: Conf. 499, 012003 (2014).
[4] D. Cocco et al., Physics Reports 974, 1 (2022).
[5] L. Rebuffi et al., Opt. Express 31(13), 21264 (2023).
[6] L. Rebuffi et al., Opt. Express 31(24), 39514 (2023).
[7] X. Shi et al., Proc. SPIE 11491, 1149110 (2020).

Speaker: Luca Rebuffi (Argonne National Laboratory)

Abstract SRI2024_Luca-Rebuffi.pdf

267 Integrating ML-Based Segmentation Into Tomography Beamtime Experiments with MLExchange

The historical limitations with data collection at synchrotron facilities have been, by and large, solved. Today, imaging beamlines can acquire 100s of tomograms per hour at a sustained rate. Similarly, high-quality 3D reconstruction of the 2D raw data is now completed within a few minutes of the last radiograph hitting the disk. Resultingly, users leave a typical tomography beamtime session with 100s of reconstructed datasets.
However, much of this collected data is not analysed and therefore remains unpublished. This is because post-processing and segmentation remain a significant challenge for experienced and inexperienced users. Specialised and costly hardware and software are required to handle 3D datasets. Still, more fundamentally, traditional computer vision algorithms are not robust against cross-sample changes in image quality that the instrument or sample preparation can introduce. As a result, many users must process each dataset uniquely. Artificial intelligence (AI) and Machine learning (ML) tools have been shown to better cope with image quality variation; however, they require a high level of technical know-how to utilise successfully.

MLExchange, a cross-facility project developed by LBNL, ANL, BNL and ORNL, has been developed to address the challenges of making AI tools readily available to users during their sessions at tomography beamlines. The framework is designed to be user-friendly and intuitive, with graphical user interfaces (GUIs) that simplify the process of using ML tools. MLExchange ties together browser-based user interfaces, workflow management, data services and machine learning packages in an integrated platform. Multiple scientific workflows are targeted, including tomographic image segmentation. For this use case, the High-Resolution Image-Segmentation application provides an intuitive browser-based interface for easily defining segment classes on slices of reconstructed images, kicking off training and segmentation jobs, and reviewing results. The system uses the DLSIA framework, which provides multiple machine-learning network implementations targeting image segmentation with an intuitive API for tuning network architectures. Data is read from and written to the Tiled data service, providing a consistent interface for image and mask data. During a beamtime, the full system was installed at the DIAD beamline and integrated into the beamline's scan and reconstruction workflow, seamlessly allowing the user to begin the annotation and segmentation process as soon as their scans are reconstructed. By leveraging the high-performance hardware already available at synchrotron facilities, users can seamlessly integrate ML tools into their research workflow, eliminating the obstacles that previously impeded their research progress.

Speaker: Sharif Ahmed (Diamond Light Source)

268 Real-Time Data Processing for Serial X-ray Crystallography

We have implemented a system for fully real-time processing of data from serial X-ray protein crystallography experiments. The system handles the full data rate from a 16 megapixel Dectris EIGER2 X detector at 133 frames per second, performing the standard serial crystallography data processing pipeline consisting of peak search, diffraction pattern indexing, spot “prediction” and integration. The processing time for each frame, on a single CPU, is much less than one second. Therefore, a small number of CPU cores (around 40) are sufficient to keep up with the data. This was achieved while handling the entire resolution of the detector: even higher speed is possible by binning the pixel values to reduce the effective number of pixels.

The system has been deployed at the P11 beamline of PETRA III, where it has been reliably used in a series of user experiments. It is based on the CrystFEL software for serial crystallography [1], in combination with the ASAP::O high-performance data framework developed at DESY [2]. Similar systems based on the same building blocks are now being tested at other experimental stations.

Real-time data processing offers many advantages. First, there is the obvious improvement in “situational awareness” during the experiment: the ability to spot problems, make improvements and know when enough data has been collected. In addition, since there is no technical need to store the detector readout data on disk, there is potential for drastic reductions in the high data storage costs which are currently associated with serial crystallography experiments. But are we ready to make the required changes to our established workflows?

This contribution will describe our real-time pipeline in detail, and discuss the implications for the way we perform experiments at large-scale facilities.

[1] https://desy.de/~twhite/crystfel/

[2] https://asapo.pages.desy.de/asapo/

Speaker: Thomas White (FS-SC)

269 Data Reduction on FPGAs

Increasing brightness of new generation light sources and developments in X-ray detectors allow faster experiments and higher data rates. Reducing data first before storing them is one of the most effective strategies of dealing with expanding data volumes. The effective and real time data reduction is also imperative to near-real time experiment feedback, dynamical events selection and data filtering. Field-programmable gate arrays (FPGAs) are very common hardware used for data acquisition, in particular detector readout, but they perform usually rather simple compute operations. With recent developments in computer science (synchronous message exchange, high level synthesis) these computer chips are also available for scientific programmers and the number of applications is increasing, including applications related to photon science experiments: spot-finding, tomographic reconstructions, simulations of small angle scattering patterns or azimuthal integration (AZINT). This contribution deals mainly with the last application of AZINT on FPGAs. Modern “compute” FPGAs can be equipped with large memory and hosted in a computer the same way as graphical processing units (GPUs). They are excellent candidates for processing high throughput detector data. All the tasks of receiving, decompressing the detector image stream and the final AZINT computation can be handled on a single device providing fixed and extremely short latencies of data processing. Optimized software allows beside others power costs reductions. Even space application can profit from the latter and from a good radiation tolerance of FPGAs. The computer software performing AZINT on FPGAs is available in the Intel DevCloud and compute infrastructure of MAX IV synchrotron laboratory. It is demonstrated the FPGA implementation can process several (>6) Giga-pixels per second on the mid-range cost and energy-effective FPGAs. That matches well the maximum frame-rates of detectors at synchrotron facilities nowadays and scales to needs of future detectors. The solution 1 allows seamless integration with standard software, in particular Python, including examples using Jupyter notebooks.

1 Z. Matěj et al., https://gitlab.com/MAXIV-SCISW/compute-fpgas/bincount

Speaker: Zdenek Matej (MAX IV Laboratory, Lund University)

270 The Automation System for TPS (Taiwan Photon Source) 31A PXM (Projection X-ray Microscopy) Endstation

The control system used at the Taiwan Photon Source TPS31A PXM endstation is composed of an integrated system capable of achieving fully automated sample scanning and data retrieval. This system consists of six main subsystems (Figure 1):
(a) Central Control System: Integrated by a computer system, allowing remote control.
(b) Sample Alignment System: Used to measure and extract the scanning center of experimental samples.
(c) Tray Changing System: Loads samples into the robotic arm sample changing system.
(d) Robotic Arm Sample Changing System: Sends samples to the rotating platform for scanning.
(e) Scanning System: Executes sample alignment and rotation to collect projection images.
(f) Storage System: A one Petabyte-sized HDD cluster used for storing and backing up projection image data.
All subsystems have been integrated, and the PXM endstation is currently available for user experiments.

Speaker: Chienyu Lee

SRI2024_CYLee_V1.docx

271 DAPHNE4NFDI - Improving Research Data Management at Synchrotron Facilities

Advancements in synchrotron and X-ray free-electron sources and associated developments in instrumentation and techniques offer many new possibilities for researchers. At the same time there is increasing demand and pressure to make measured data accessible to the wider community through improved research data- and metadata- management, and for implementation of FAIR data principles by which data should be made Findable, Accessible, Interoperable and Reusable.

The consortium DAPHNE4NFDI (DAta from PHoton and Neutron Experiments for NFDI) addresses this challenge within the German National Research Data Infrastructure (NFDI), and also in relation to European/worldwide initiatives [1]. DAPHNE4NFDI engages directly with the user community to develop user-driven data solutions and infrastructure for the wider photon and neutron community, based on solutions designed by and that work for the user community. Specifically, new data management and analysis schemes are developed, metadata capture for re-use with searchable catalogues is deployed, and on-the-fly data analysis and reduction is being developed in the consortium.

This presentation will give an overview of our activities and elaborate on our progress, showcasing progress in some of our use-cases including:

(1) X-ray reflectivity: In addition to electronic laboratory notebooks and persistent sample identifiers, the use case has developed ML-based data analysis [2,3]. This includes “ML-readiness” of (meta)data, beamline integration, and a reference data collection for ML model training and validation.

(2) X-ray imaging for biological matter: Is serving as a test bed for integrating electronic laboratory notebooks with data collection and analysis, for both large scale facilities and laboratory measurement systems.

(3) X-ray photon correlation spectroscopy (XPCS): To automatically create a customizable and comprehensive overview of the experiment we have integrated time-resolved XPCS analysis into the EuXFEL metadata preview tool DAMNIT [4].

(4) X-ray absorption spectroscopy: A curated reference database is being developed to save beamtime and increase analysis efficiency. The database has been created for XANES/EXAFS in the first phase [5] and will be extended to XES.

References
[1] A. Barty et al., Zenodo, 2023, DAPHNE4NFDI - Consortium Proposal, https://doi.org/10.5281/zenodo.8040606
[2] L. Pithan, et al., J. Synchrotron Rad. 30 (2023) 1064.
[3] A. Hinderhofer et al., J. Appl. Cryst. 56 (2023) 3.
[4] https://damnit.readthedocs.io (accessed 2024-04-06)
[5] A. Gaur, et al., Proc Conf Res Data Infrastr 1 (2023), https://doi.org/10.52825/cordi.v1i.258

This work was supported by the consortium DAPHNE4NFDI in the context of the work of the NFDI e.V. The consortium is funded by the DFG - project number 460248799.

Speaker: Lisa Amelung (DAPHNE4NFDI (DESY FS-SC))

272 Data Reduction Strategy at the European XFEL

The European XFEL is a megahertz repetition-rate facility producing extremely bright and coherent pulses of duration of the order of few femtoseconds or less. Owing to its X-ray imagers, specifically built to operate at these repetition rates (AGIPD, DSSC and LPD), the amount of data generated in the context of user experiments can exceed hundreds of gigabits per second, resulting in tens of petabytes stored every year. These rates and volumes pose significant challenges both for the facility and its users. In fact, if unaddressed, extraction and interpretation of scientific content is hindered, and investments and operational costs quickly becomes unsustainable.

We are working, in close collaboration with our users, to address the above-mentioned topics at different levels. On the administrative level, we largely revisited our scientific data and retention policies so as to establish a framework for data reduction, and includes provision of open and FAIR data. Then, we are also introducing comprehensive data management plans, to streamline and enhance facility-users communication, including requirements and agreements on services and methods. On a technical and scientific level, we are upgrading our data systems to incorporate data reduction tools and methods [1,2], which are either developed inside or outside the facility. Finally, we are developing extensive metrics to assess reduction quality, and to corroborate automation of reduction processes.

In this talk I will highlight challenges and solutions implemented to date, and detail our vision for user-centric data reduction [2].

[1] Schmidt P, et.al. (2024) Turning European XFEL raw data into user data. Front. Phys. 11:1321524. doi: 10.3389/fphy.2023.1321524
[2] Sobolev E, et.al. (2024) Data reduction activities at European XFEL: early results. Front. Phys. 12:1331329. doi: 10.3389/fphy.2024.1331329

Speaker: Egor Sobolev (European XFEL)

sobolev_data_reduction_at_euxfel_SRI2024.pdf

Mikrosymposium 5/2: Operando Investigations: MS5/2

273 Exploration of cathode materials for Li-S batteries via X-ray spectroscopy

Recently, a lot of efforts have been devoted into lithium-sulfur (Li-S) battery system due to its high theoretical capacity (1675 mAh g-1) and low cost, which could be a competitive candidate for the next-generation batteries in the future. However, it suffers from a poor cycling stability during charging-discharging, which is blamed to the “shuttle effects” of lithium polysulfides [1]. Meanwhile, it is also challenging to reach a high capacity (≥1400 mAh g-1) for lithium sulfur batteries because of the insulated Sulfur and Li2S. In our study, functional metal oxide/metal sulfide/metal nitride nanoparticles with defined shape and composition have been designed and synthesized via colloidal approach using polymeric particles as soft template, which can be applied as electrode materials for Li-S batteries with significantly improved electrochemical performances [2-4].
In addition, fundamental understanding of the formation and dissolution processes of both solid phases, S8 and Li2S, is necessary for further improvement of the rate capability of Li-S cells. Synchrotron-based operando high-resolution X-ray imaging has been successfully used for the detailed morphology study of macroscopic sulfur particles during cycling of the battery cells [5]. And using small-angle X-ray scattering, a better understanding of the elucidation of structure-morphology-property-relationships promotes the development of carbon-based sulfur host materials [6]. More recently, we have developed MoS3-based freestanding cathode by deposition of MoS3/ polypyrrole (PPy) nanowires on the porous nickel foam via electrochemical methods. A mechanism study has been performed via taking advantages of this porous, binder-free, and free-standing cathode using X-ray absorption near edge spectroscopy (XANES) to investigate the evolution of the chemical and electronic structure of Mo and S species during discharge/charge processes. The formation of lithium polysulfides was excluded as the driving cathode reaction mechanism revealing the promising property of MoS3 as a sulfur-equivalent cathode material for Li-S batteries [4].

References:
[1] Q. Pang, X. Liang, C. Y. Kwok, L. F. Nazar, Nat. Energy 2016, 1, 16132.
[2] D. Xie, Y. Xu, Y. Wang, X. Pan, E. Härk, Z. Kochovski, A. Eljarrat, J. Müller, C. T. Koch, J. Yuan, Y. Lu, ACS Nano 2022, 16, 10554–10565.
[3] S. Mei, C. J. Jafta, I. Lauermann, Q. Ran, M. Kärgell, M. Ballauff, Y. Lu, Adv. Funct. Mater. 2017, 1701176.
[4] H. Yu, A. Siebert, S. Mei, R. Garcia-Diez, R. Félix, T. Quan, Y. Xu, J. Frisch, R. G. Wilks, M. Bär, C. Pei, Y. Lu, Energy & Environ. Mater. 2024, e12757.
[5] P. Feng, K. Dong, Y. Xu, X. Zhang, H. Jia, H. Prell, M. Tovar, I. Manke, F. Liu, H. Xiang, M. Zhu, Y. Lu, Adv. Fiber Mater. 2024, 6, 810-824.
[6] E. Härk, B. Kent, S. Risse, R. Müller, M. Ballauff, Y. Lu, Acta Cryst. 2021, A77, C321.

Speaker: Yan Lu (Helmholtz-Zentrum Berlin für Materialien und Energie)

274 Understanding the real-time structural evolution of battery materials during function

A large fraction of world-wide research focuses on making better battery materials, hence better batteries to meet the demands of current and emerging applications. This talk will focus on understanding the impact of a materials’ atomic scale structure and its evolution on battery performance.

A large proportion of the function of batteries arises from the electrodes, and these are in turn mediated by the atomic-scale perturbations during an electrochemical process (e.g., battery use). We use a combination of techniques, ex situ, in situ and operando to understand how atomic scale evolution impacts performance. In particular, the operando work results in an atomic level “video” of device function which can be directly correlated to performance parameters such as energy density, lifetime (or degradation), rate capability and safety. Examples using operando neutron and synchrotron powder X-ray diffraction to probe lithium- and sodium-ion battery materials and ex situ solid-state NMR to probe lithium-sulfur battery materials will be presented. In particular, our work on pushing the boundaries of such experiments will be described, e.g., operando neutron diffraction studies of batteries at different temperatures. The intention is to build up the most complete structural picture of a battery, to determine how crystallography and electrochemistry are related.

Speaker: Neeraj Sharma (UNSW)

275 In Situ Photo-Electrochemical Investigation Using Surface X-ray Diffraction: From Ultra-High Vacuum to Solid/Eelectrolyte Interfaces

A custom apparatus was developed at I07 Surface and Interface Diffraction beamline, Diamond Light Source (DLS) to perform operando measurements of solid/electrolyte interfaces under external potential and UV illumination using surface X-ray diffraction (SXRD).
Samples can be prepared under ultra-high vacuum (UHV) using standard methods in DLS Surface and Interface Laboratory. Pre-characterisation such as low energy electron diffraction, scanning tunnelling microscopy and X-ray photoelectron spectroscopy (LEED, STM, XPS) can be performed prior to transferring the sample under UHV to the Photo-ElectroChemical DrOplet Cell (PEC-DOC). The PEC-DOC is then transferred and mounted of I07’s EH1 diffractometer for SXRD structure determination under UHV. A custom liquid delivery device comprising a working and reference electrodes is then introduced in the chamber under controlled atmosphere. A droplet of electrolyte is contacted to the surface using an endoscope, also utilised to monitor the shape of the droplet during acquisition.
Using the PEC-DOC, the electrical double layer of the TiO2(110) interface with 0.1 M KCl(aq) has been elucidated. This represents an insight into the behaviour of the semiconductor in a neutral interface to define the structure of the electrical double layer present. The electrochemical capabilities of the PEC-DOC enabled cyclic voltammograms of the surface interface to be recorded. It also allowed a bias voltage to be applied for SXRD measurements, providing a tentative insight into the electrochemical desorption taking place as a result of applied positive potential.
This work was supported by the European Research Council Advanced Grant ENERGYSURF to GT, EPSRC (EP/L015862/1). AW has received funding from the European Union’s research and innovation programme under the Marie Sklodowska-Curie grant GA No 665593.

Speaker: Axel Wilson (CNRS)

Figure.PNG

276 Interface Sensitive Drain Current X-ray Absorption Measurements of Operando Electrochemical Cells

Electrochemical processes depend on several phenomena, such as water-ion interactions, diffusion, adsorption and the chemical state of the electrode surface. These processes occur in a thin layer at the electrolyte/electrode interface, the electrical double layer (EDL). The required interface sensitivity to investigate the EDL is challenging to achieve due to a lack of techniques that are compatible with operando electrochemical cells. In fact, the commonly used fluorescence yield mode of operando X-ray absorption spectroscopy (XAS) is considered as a bulk sensitive measurement. Here we describe a novel detection technique for XAS by using the drain current of the electrochemical working electrode to achieve the required interface sensitivity. Usually, the XAS drain current is buried below the several orders of magnitude higher electrochemical current and cannot be accessed. To overcome this issue, the X-ray beam was amplitude modulated by a mechanical chopper that was implemented in the UE56/2-PGM1 beamline at BESSY II. We have developed advanced separation electronics that are capable of separation the modulated drain current (AC) from continuous electrochemical current (DC). The new electronics provide a high dynamic range for the AC signal, efficient filtering of noise introduced by the potentiostat, and they are transparent for the operation of the electrochemical cell. The capabilities of this approach were shown by in-situ electrodeposition of copper using the detection of O K-edge and Cu L-edges. This technique enables the investigation of the surface structure of the deposited Cu, the concentration of the dissolved Cu ions in the EDL and the interfacial water structure. We found that the deposition occurs via Cu2O/CuOH intermediates followed by a reduction to metallic copper rather than a direct process. This result highlights the complexity of interfacial electrochemistry, and the need to resolve it in molecular-level detail.

Speaker: Patrick Zeller (Fritz-Haber-Institut der Max-Planck-Gesellschaft)

277 In Situ Laue Diffraction Study on Forming Mechanism of Additively Manufacturing Nickel-Based Single-Crystal Superalloy

Directly printing nickel-based single-crystal (SX) superalloy blades with intricate heat dissipation structures using additive manufacturing is a crucial technology for enhancing turbine front temperatures and reducing production costs [1]. However, this process presents significant challenges. During printing, a focused laser beam rapidly melts the substrate and powders, creating an extreme non-equilibrium metallurgical environment affected by multiple physical fields. Consequently, maintaining the perfection of SX structures becomes challenging. Common issues such as stray grains (SGs) [2] and crystal rotation [3] hinder the additive manufacturing of single crystals.
To address these challenges, we developed an in situ experimental setup for additive manufacturing of SX materials based on the Beijing Synchrotron Radiation Facility 3W1 beamline. Our current primary focus was investigating the internal microstructure evolution mechanism of nickel-based SX superalloy during single-layer laser melting and laser powder bed fusion processes [4]. By employing in situ synchrotron radiation Laue diffraction, we captured transient crystal rotation behavior and the formation process of SGs. Additionally, we conducted thermomechanical coupled finite element simulations and molecular dynamics simulations to further understand the underlying mechanisms.
Our findings reveal that the deformation gradient resulting from localized heating/cooling heterogeneity plays a critical role in crystal rotation, while sub-grain rotation induced by rapid dislocation movement and complex stress fields may be the main mechanism for SGs formation at the bottom of the melt pool. Furthermore, we investigated the influence of substrate orientation on crystal rotation and SGs formation mechanisms during multiple-layer deposition via in situ Laue diffraction.
An in-depth understanding of crystal rotation and SGs formation mechanisms is instrumental in optimizing additive manufacturing approaches to achieve products with SX texture.

Figure 1 (a) Picture of the in situ Laue diffraction system during additive manufacturing process. (b) Time series of the representative Laue diffraction patterns during laser melting processes.

References:
[1] Journal of Laser Applications, 2014, 27(S1): S17004
[2] Acta Materialia, 2021, 205: 116558
[3] Scientific Reports, 2021, 11(1)
[4] Nature Communications, 2023, 14(1): 2961.

Speaker: Dongsheng Zhang

figure_1.PNG

278 Sub-Second Time Resolution Reciprocal Space Mapping for Observation of III-V Semiconductor Thin-Film Growth

In-situ reciprocal space mapping during thin-film growth provides important information for understanding growth processes, like lattice relaxation and the generation of defects [1]. It is a challenge, however, to achieve time resolutions below the seconds range. In this contribution, we present a high-speed reciprocal space mapping method that can be used for in-situ observations of non-repeatable phenomena with a time resolution 100 ms and less, and its application to the growth of III-V semi-conductor thin films.
Experiments were conducted at the undulator beamline 11XU of SPring-8, where a surface X-ray diffractometer combined with a molecular beam epitaxy chamber is installed. An X-ray optical system was set up in the experimental hutch to transform the collimated and monochromatized synchrotron radiation beam entering the hutch into a convergent X-ray beam with a wide range of incident angles onto the sample. By observing the intensity distribution of the X-rays diffracted at the sample with a two-dimensional detector, the scattering distribution in a wide range of momentum transfer can be observed simultaneously with a single detector exposure.
The setup was used to observe the growth of InGaAs on GaAs(001) and of InGaN on GaN. The initial stages of the growth as well as the relaxation of the films when the thickness increased were observed with a time resolution of 100 ms.
In addition to high-speed reciprocal space mapping at monochromatic 3rd generation synchrotron beamlines, the method might also be useful for simultaneous observation of an extended region of reciprocal space using a single pulse from an XFEL source.
[1] M. Takahasi, Jpn. J. Appl. Phys. 57 (2018) 050101.

Speaker: Wolfgang Voegeli (Tokyo Gakugei University)

279 Grazing Incidence Diffraction and Scattering with High-Energy X-rays: Recent Innovations at Beamline P07 @ PETRA III

Grazing incidence (GI) geometry, i.e. the illumination of a sample at very shallow angle on its surface and the creation of an evanescent wave parallel to the surface, is the foundation for x-ray diffraction and scattering studies of surfaces, interfaces and very thin films. At high x-ray energies (>50 keV), not only the Bragg angles are small, but also the critical angles of total external reflection assume low values <0.01° even for high-Z materials. In the second experimental hutch (EH2) of the high-energy beamline P07 at PETRA III [1], DESY offers the capabilities to routinely apply GI geometry by providing instrumentation of the necessary precision for sample alignment as well as tight focusing in the vertical to a few micrometers in order to keep the projected footprint on the surface short on the order of a few millimeters. The available large and fast area detectors for high-energy x-ray applications capture an extended range in reciprocal space in a single exposure within fractions of a second and thus record many different lattice planes simultaneously in real time that otherwise must be collected in time-consuming sequential measurements.
After the pioneering work on fast determination of surface reconstruction and phase formation during catalytic reactions at the gas-solid interface over single-crystal surfaces by Gustafson et al. [2], many more high-energy surface diffraction studies have followed using similar model catalysts and analyzing Bragg reflections and crystal truncation rods. This presentation highlights current advances of this technique at P07 e.g. operando (electro)catalysis with microsecond time resolution. [3]
Building onto the expertise in high-energy surface diffraction, we developed the beamline’s capabilities for total scattering in grazing incidence to study the local atomic structure of thin films in real space by pair distribution function (PDF) analysis. The PDF is an intuitive tool to investigate the short-range order of amorphous and nanocrystalline materials as well as local disorder in periodic polycrystalline structures. We have achieved unprecedented sensitivity to layer thicknesses down to a few nanometers at time resolution in the range of seconds for the collection of individual 2D total scattering patterns up to high momentum transfer >20 Å-1 and even separated and resolved the signals from bilayer structures [4]. Recent in situ deposition and crystallization studies [5] showcase the method’s strength as a unique tool to follow structural transitions in thin films between states of low and high degree of ordering. In this regard, especially the successful implementation of a laser-interferometer based sample stabilization system for variable temperature heat treatment is a major achievement to track the structural changes e.g. during post-deposition annealing typically applied in sputtering or atomic layer deposition.
[1] F. Bertram et al., AIP Conf. Proc. 1741 (2016) 040003, doi.org/10.1063/1.4952875
[2] J. Gustafson et al., Science 343 (2014) 758, doi.org/ 10.1126/science.1246834
[3] L. Jacobse et al., Rev. Sci. Instrum. 93 (2022) 065111, doi.org/10.1063/5.0087864
[4] A.-C. Dippel et al., Nanoscale 12 (2020) 13103, doi.org/10.1039/d0nr01847c
[5] M. Roelsgaard et al., IUCrJ 6 (2019) 299, doi.org/10.1107/S2052252519001192

Speaker: Ann-Christin Dippel (FS-PETRA-D (FS-PET-D Fachgruppe P07211))

16:00 Coffee Break

16:30 Prize - Award Session

17:10 Closing Session