Scientific Opportunities with very Hard XFEL Radiation

18 Jan 2023, 00:20 → 20 Jan 2023, 14:30 Europe/Berlin

Auditorium (DESY)

The workshop “Scientific Opportunities with very Hard XFEL Radiation” will be held at the German Electron Synchrotron DESY in Hamburg, Germany. It aims at identifying scientific questions and applications requiring very hard XFEL radiation (> 40 keV) in the context of future upgrades of the source and instruments of the European XFEL.

The workshop will bring together scientists from all over the world to present and discuss scientific opportunities and novel techniques that can leverage very hard XFEL radiation.

 

Wednesday, 18 January

1 Opening

Speaker: Sakura Pascarelli (European XFEL)

Applied materials and industrial applications: Plenary Session

2 Introduction

Speaker: Sakura Pascarelli (European XFEL)

3 Perspective for material under shock induced by laser: processes and material under extreme conditions

This presentation concerns challenges in relation with planetary security (Dart Mission), spacecraft protection against debris, lightening (NDT/SHM) and life extension of structures (LSP).

In the first two cases, shocks induced by laser plasma reproduce pressure loadings involved in High Velocity Impact (HVI)(7-30 Km/s):
-to model physics,
-to select material,
-to design stacks of material
-to optimize coupling
-to provide set of datas for code validation.

Main objective is the design of new technologies to improve coupling projectile/target, to help mission impact (DART/HERA), to discover innovative materials (like metallic glass) and geometries for structural protection.

Studies concern :
-laser ablation to controlHVI/analogy
-material under shock (shock wave propagation, damaging, crater formation, phase change)
-cloud of debris physics (generation, flight, particle size, phase change, impact on surface, reactivity with atmosphere)
Synthetic and natural material are concerned : metals, glasses, silicium, composite and polymers, ceramics, powder/sand, rocks.

At present time and for near future (1-3 year), in-situ diagnostics should be focused
-on visible imaging and velocimetry (VISAR/PDV)
-on residual impact on material (crater and bulk material) and debris recovered afterwards.

However, mid/long term researches will go towards time and space resolved diagnostics (Hard X-Ray)
-to observe shock wave propagation material (which volumes are in the range of mm3)
-to observe crater formation (depth in the range of mm)
-to measure density at um/ns scales and velocity of debris
-to detect phase changes/chemical synthesis at grain scale in bulk and in debris (Example : Hydratation controversy)
-to study secondary impact of debris on surface (solid or/and covered by particle) and clouds collision
Issues are also related to large time (ps to us) and space (nm to mm) ranges.

Concerning NDT/SHM and LSP topics, needs join these challenges of time/space resolved diagnostics in bulk material (CFRP and metal) :
to measure residual stresses fields
to observe delamination/fissure propagation in Carbone Fiber Reinforce Polymer and metal.
The final aim is a breakdown in modeling for digital twin for LSP and life time prognostic for SHM.

Speaker: Laurent Berthe (CNRS/PIMM)

4 Why hard XFEL is needed to image additive manufacturing processes in real and reciprocal space

Additive Manufacturing (AM), both Laser Powder bed Fusion (LPBF) and Laser Blown Powder Directed Energy Deposition (LBP-DED) promise to produce unique, high quality components for aerospace to biomedical applications with unprecedented geometric complexity. However, the underlying physics controlling the melting, solidification, flow and other phenomena are still poorly understood. Many groups are modelling these processes, but experimental investigations are limited by the very high cooling rates (103 – 105 C/s), flow rates and interface velocies (m/s). Here, we present the need for ever faster and high flux real and reciprocal space imaging of microstructural feature formation and highly non-equilibrium phase changes. This is done using two unique in situ and operando LPBF and LBP-DED rigs that correlatively image the process using synchrotron X-ray, optical and infra-red imaging to capture the underlying phenomena that control AM. The benefits and limitations of the imaging modalities are discussed, together with the opportunities a hard XFEL could provide.

Speaker: Prof. Peter Lee (UCL Mechanical Engineering, University College London)

XFEL_PDLee_230118.docx

10:35 Break

5 Time resolved high energy x-ray diffraction from nanostructures and interfaces

In the recent years we have established high energy surface sensitive X-ray diffraction as novel tool for the investigation of surfaces and nanostructures. It allows a significant acceleration of the measurements, making fast kinetic processes in in-situ and operando experiments accessible, which could not be addressed before [1-5]. These experiments allow to address fundamental processes in heterogeneous catalysis and electrocatalysis involved in energy production and conversion processes. Due to the large Ewald sphere at high photon energies in the 70-80 keV regime in combination with large 2D detectors, reciprocal space maps from nanoparticles can be obtained, allowing orientation, size and shape determination in stationary measurement geometries at elevated gas pressures and in the presence of electrolytes. Further on, using high energy photons, diffuse scattering from defects in solids can be investigated. In an ultrafast optical pump – hard x-ray probe experiment from metal nanoparticles employed as heterogeneous catalysts reciprocal space mapping can be performed without the need of additional sample scanning, which speeds up the experiment and will make transient diffraction signals from nanoparticle facets accessible. This can be related to light induced nanoparticle shape changes and ultrafast structural rearrangements possibly leading to more active catalysts for reactions relevant for the hydrogen economy, such as methanol synthesis, methane combustion or ammonia synthesis.

[1] P. Nolte, A. Stierle, N. Kasper, N. Y. Jin-Phillipp, H. Reichert, A. Rühm, J. Okasinski, H. Dosch, S. Schöder, Phys. Rev. B 77, 115444 (2008), 10.1103/PhysRevB.77.115444
[2] L. Jacobse, V. Vonk, I. Mccrum, C. Seitz, M. Koper, M. Rost, A. Stierle,
Electrochimica Acta 407, 139881 (2022) 10.1016/j.electacta.2022.139881
[3] U. Hejral, P. Müller, M. Shipilin, J. Gustafson, D. Franz, R. Shayduk, U. Rütt, C. Zhang, L. R. Merte, E. Lundgren, V. Vonk, A. Stierle, Phys. Rev. B 96, 195433 (2017) 10.1103/PhysRevB.96.195433
[4] U. Hejral, P. Mueller, O. Balmes, D. Pontoni, A. Stierle, Nature Communications 7, 10964 (2016) 10.1038/ncomms10964
[5] P. Müller, U. Hejral, U. Rütt, A. Stierle, Phys. Chem., Chem. Phys.16, 13866 (2014) 10.1039/c4cp01271b
[6] J. Gustafson, M. Shipilin, C. Zhang, A. Stierle, U. Hejral, U. Ruett, O. Gutowski, P.-A. Carlsson, M. Skoglundh, E. Lundgren, Science 343, 758 (2014) 10.1126/science.1246834

Speaker: Andreas Stierle (CXNS, DESY)

6 Applications for Very Hard XFEL Radiation at First Light Fusion in Support of Projectile-Driven IFE Research

First Light Fusion (FLF) is a private UK company investigating a novel approach to inertial fusion energy (IFE), through means of hyper-velocity projectile-driven impact. Using a combination of a proprietary shock pressure amplification technology and a metallic-cased fuel-containing target, we are pursuing the goal of achieving fuel gain [1] in a quasi-spherical, volume ignition configuration [2]. The drive for the system will be provided by our next generation pulsed power machine, M4, which is presently in the preliminary phase of its engineering design.

A key aspect of how FLF’s end-to-end concept will be deployed involves the fielding of a physically coupled amplifier-target system, both components of which will be encased in a dense, high-Z metal shell. This is crucial to the operation of the amplifier and facilitates the hydrodynamic compression of the fuel and efficient radiation recycling to reduce losses from the fuel. Validation of the internal shock dynamics, thermal and radiative transfer and plasma microphysics modelling underpinning the function of these components, especially the implosion of the fuel-filled cavity, are thus of crucial importance. Furthermore, in an age where computer-driven design and
optimization techniques are playing increasingly prominent roles in tackling engineering and physics challenges, the need for high-quality, extensive constitutive data for a diverse range of materials is paramount. Hard X-rays in particular facilitate a number of state-of-the-art diagnostic techniques for gathering such data.

In this contribution we present a general overview of FLF’s projectile-driven approach to IFE, some examples of how X-ray diagnostics have contributed to the early successes of our scientific programme, and how we are supporting diagnostic development to meet our future needs and challenges. Two applications of particular interest to this workshop are: 1) the fielding of a portable two-stage light-gas gun at the European Synchrotron Radiation Facility for the study of shock-driven cavity collapse [3]; and 2) exploring the potential of a novel, model-independent temperature diagnostic for matter under extreme conditions [4]. Both applications are ideally suited to hard XFEL radiation and would serve to strengthen the knowledge base supporting the next generation of our experiments.

References:

1. https://www.llnl.gov/news/nif-experiments-show-initial-gain-fusion-fuel
2. K. Molvig et al. “Low Fuel Convergence Path to Direct-Drive Fusion Ignition”, Phys. Rev. Lett. 116, 255003 (2016).
3. E. M. Escauriza et al., “Collapse Dynamics of Spherical Cavities in a Solid Under Shock Loading”, Sci. Rep. 10, 8455 (2020).
4. T. Dornheim et al., “Accurate Temperature Diagnostics for Matter Under Extreme Conditions”, Nat. Commun. 13, 7911 (2022).

Speaker: Hugo Doyle (First Light Fusion Ltd)

2023_EuroXFEL_workshop_abstract_DChapman.pdf

7 Multiscale materials science: movies of irreversible processes within realistic environments

Crystalline materials are ubiquitous. The performance of metals, ceramics and semiconductors is critical for addressing societal challenges; geoscience relates to rocks, ice and sediments while biomineralisation is an integral part of biology and Health technology. The physical and mechanical properties of such materials is often governed by their structure, which tend to be organized on many length scales in a hierarchal way. Associated with this are competing dynamics spanning many time scales. Probing these simultaneously is notoriously difficult as one needs to probe a volume that is representative of all length and time scales in a non-destructive way. Another complication is that structural processes such as phase transformations, nucleation-and-growth and damage are typically non-reversible. Today the science of crystalline materials is founded on a posteriori data. Better understanding of the dynamics is essential to fulfil visions of “materials design in the computer” as well as for optimisation of existing components and devices.

A hard x-ray microscope in the range 20-80 keV at the EuXFEL has the prospect of overcoming this limitation. Recently the propagation of acoustic waves in mm sized crystals were visualised at 10 keV by diffraction contrast with 1 µm and <1 ps resolution. We propose to make a dedicated set-up for both dark and bright field movies of irreversible phenomena at the repetition rate of the XFEL. The extended x-ray energy range is critical to provide penetration power in order to study medium and high Z elements and devices in general under realistic conditions.

The science case includes:

• Direct observation of martensitic transformation in steel and shape memory alloys as well as dislocation dynamics during plastic deformation – fundamental materials science with a high socioeconomic impact
• Domain switching in ferroelectrics and dielectric breakdown, for introduction of a new generation of power capacitors as part of the green transition
• Interaction of defects and grain boundaries with thermal or optical waves, e.g. for understanding metamaterials and seismic waves in the mantle of the Earth.
• Engineering: e.g. additive manufacturing and damage
• Extreme condensed matter.
• Movies of magnetic domains evolution, e.g. pinning and melting of the Abrikosov lattice in type II superconductors

Speaker: Henning Friis Poulsen (DTU Physics)

8 Panel discussion and conclusions

13:00 Lunch break in the DESY canteen

Structural dynamics in disordered materials in real and reciprocal space: Plenary Session

9 Introduction

10 Structure, properties and phase transitions of melts and glasses at in-situ conditions within Earth and rocky planets

Silicate and Fe compound melts are major constituents of the interior of the Earth and rocky planets and have a strong impact on their evolution and properties. Despite this importance, information on properties of such melts at in-situ conditions are still scarce. Main reasons for this are, that these melts are not directly accessible and that experiments at in-situ conditions are extremely challenging, especially if flux hungry techniques will be applied. In addition, the properties change widely with pressure, temperature and the chemical composition opening up a wide parameter range.
Most high-quality actual information on structure of amorphous silicates is obtained with X-ray Raman (XRS) and total scattering analysis (PDF) on SiO2 glass or GeO2 as analogue for SiO2 (Prescher et al., 2017, Spiekermann et al., 2019, Petitgirard et al., 2019, Morard et al., 2020) at room temperature during static compression in a diamond anvil cell (DAC) and additionally X-ray emission spectroscopy (XES) in case of Fe-bearing systems. More recent studies expanded the temperature range to in-situ conditions by the application of either laser or X-ray heating within the DAC (Liermann et al., 2021; Kaa et al., 2022; Morard et al., 2022).
Another emerging way to study melts at in-situ conditions is the use of optical long pulse laser dynamic compression techniques that allow to achieve the most extreme pressure-temperature (P-T) states in the laboratory. The extreme states are only very short lived (nanosecond scale) and nowadays can be probed either with hard synchrotron or X-ray free electron laser (FEL) radiation. The short pulse length of the FEL radiation allows to obtain fs long snapshots of the material while it is excited to extreme temperatures and pressures. By the application of pump-probe techniques, the evolution of the sample during dynamic compression can be studied with great time-resolution and short-lived states of extreme conditions can be accessed (Briggs et al., 2019; Schoelmerich 2020; Armstrong et al., 2021). Most importantly, studies by dynamic compression have the advantage that the sample does not need to be constrained in a sample container that might mask the signal or react with the sample while the measurement is performed. However, all studies that were performed so far at FELs are limited in the accessible Qmax of 7. Since detector geometries have been optimized already, this limitation mainly originates from the restriction in the availability of higher photon energies. This maximum Q is considerably lower to what has been achieved at synchrotron sources (e.g. 10 in Prescher et al., 2017) and poses limitations to push forward the scientific knowledge.
Higher photon energies at an FEL source have the unique potential to overcome the present limitations at in-situ conditions by significantly increasing the Q range and thus strongly improving the quality of structural data that can be obtained from melts and glasses at in-situ conditions. For Earth science applications this will result in significantly better models for melt properties and planet evolution and add key input to a long lasting scientific question. Besides the application to systems which are relevant for Earth sciences, the method will certainly also be applied to study glasses of industrial and everyday relevance like mobile phone displays (Panzerglas) or window glasses.

Prescher, C. et al. (2017) PNAS 114, 10041; Spiekermann, G. et al. (2019) Phys. Rev. X 9, 011025; Petitgirard et al. (2019) Geochem. Persp. Let. 9, 32; Morard, G. et al. (2020) PNAS 117, 1198; Liermann et al. (202) JSR, 28 ; Kaa et al. (2022) PRR 4; Morard et al. (2022) JGR 127; Briggs et al. (2019) APL, 115; Schoelmerich (2020) PhD thesis, University of Rostock; Armstrong et al (2021) JOM, 73.

Speaker: Karen Appel (European XFEL)

11 Ultra-fast total scattering/pair distribution function measurements using hard XFEL beams

X-ray total scattering (TS), and its Fourier transform the pair distribution function (PDF), has become the method of choice for determining structural disorder within materials since the advent of high-energy synchrotron X-ray diffractometers. To date these techniques have not transferred to XFEL facilities because of their more modest (< 20 keV) beam energies. This is slowly changing, and the increases is XFEL energies towards 30 keV is opening up the possibilities for uf-TS/PDF measurements with useful, albeit still modest, resolution. This talk will discuss how instrumentation using existing high energy XFEL beams might be optimised for uf-TS/PDF measurements and the scientific opportunities should higher-still X-ray energies become available at XFELs.

Speaker: Prof. David Keen (ISIS Facility)

12 Ultrafast lattice dynamics in halide perovskite nanocrystals by reciprocal space total scattering analysis

Recently emerging as the next generation semiconductor materials strongly impacting photovoltaics and other relevant technological sectors, lead halide perovskites, LHPs, [APbX3, A = Cs+, CH3NH3+ (methylammonium, MA) or CH(NH2)2+, formamidinium, FA; X = Cl- , Br-, I-] have also been disruptive in the field of colloidally synthesized semiconducting nanocrystals. Bright and narrowband (< 100 meV) photoexcited emission can be easily tuned from the ultraviolet to the near-infrared ranges by playing with either mixed halide composition or nanocrystals size and shape control, through facile low-temperature synthesis. Analogously to the bulk materials, the crystal structure typically consists of a 3D framework of corner-sharing PbX6 octahedra arranged in a cubic lattice or its slightly distorted modifications. Due to the soft nature of the lattice, these modifications imply small octahedral tilting that stabilizes lower-symmetry (tetragonal or orthorhombic) polymorphs, depending either on the chemical composition or temperature. [1]
Preserving the 3D connectivity of the PbX6 lattice is fundamental, being it at the origin of both the electronic band structure and (together with the unique defect-tolerance and lattice flexibility) the corresponding uncommon semiconducting properties and photodynamics. Within this scenario, the role of size and surface effects in either controlling the polymorphic stability of LHP nanocrystals or inducing other structural/lattice distortions, and the nature of disorder (local or static vs dynamic) is currently poorly understood. Unveiling and quantifying these effects in below 10 nm nanocrystals is a challenging task. [1]
X-ray total scattering methods in reciprocal space are recently emerging as powerful tools for investigating ultrasmall nanocrystals, grounded on the Debye Scattering Equation pattern calculation from atomistic models of nanocrystals that simultaneously encode both relevant atomic (structure and defects) and nanometer (finite size and morphology) length scales within a unified description. Based on this approach, local octahedra tilting persistent in small subdomains at high temperature was pointed out in fully inorganic CsPbX3 nanocrystals while they exhibited an apparent average high-symmetry cubic lattice. Cooperative halide rotations at the sub-domains twin boundaries and order-disorder phase transition were further inferred. [2] Analogously, sub-Angström Br ions displacement leading to locally tilted PbBr6 octahedra was detected in hybrid organic-inorganic FAPbBr3 nanocrystals, without apparently breaking the average cubic symmetry over the nanocrystals volume. [3] For these hybrid nanocrystals, phase transition to lower-symmetry polymorphs is still a matter of debate.
The microscopic origin of peculiar optical behavior and photodynamic of LHPs is currently the focus of intense research. One most debated phenomenon is the long lifetime of excitons (in the nanosecond range in NCs) and diffusion lengths. One possible explanation of such slow hole-electron recombination rate calls into question the formation and relaxation of large polarons (originating from strong exciton-phonon coupling) on a sub-picosecond timescale. [4] Ultrafast time-resolved X-ray total scattering experiments may greatly contribute to shed light on the phenomenon by directly observing related lattice/structural dynamics. Recent experiments from femtosecond-resolved, optical pump-electron diffraction probe on fully inorganic and hybrid LHP nanocrystals will be presented and will help to illustrate the potential of ultrafast X-ray Total Scattering in reciprocal space as a quantitative analysis tool of photoexcited out-of-equilibrium transient states and photodynamics in semiconductor ultrasmall nanocrystals. [5]

[1] Kovalenko et al., Science 358, 745–750 (2017)
[2] Bertolotti et al., ACS Nano 2017, 11, 3819−3831
[3] Protesescu et al., J. Am. Chem. Soc. 2016, 138, 14202−14205)
[4] Mahata et al.,J. Phys. Chem. Lett. 2019, 10, 1790−1798
[5] Yazdani et al.,J. arXiv:2203.06286

Speaker: Dr Antonietta Guagliardi (Institute of Crystallography, National Research Council, Como, Italy)

15:45 Break

13 Towards pump–probe single-crystal XFEL refinements for small-unit-cell systems

X-ray crystallography on macromolecular compounds has seen significant progress through X-ray free electron laser (XFEL) studies (Chapman et al., 2011, 2014; Schlichting, 2015). This is, among other things, because the short pulse durations of serial femtosecond crystallography essentially remove all effects of beam damage and atomic motion, and because the extreme brilliance reduces the crystallite size required for sufficient scattering intensity.
Recently, a dedicated pipeline for small unit-cell systems (Figure 1) has been published (Støckler et al. 2023) capable of handling of all steps of data reduction from spot harvesting to merged structure factors and has successfully solved the structure of K4[Pt2(P2O5H2)4] 2(H2O). There are still challenging aspects for which a higher energy might be the answer. Particularly the partiality correction critically relies on the accurate determination of the crystal orientation which is complicated by the low number of diffraction spots for small-unit-cell systems. Here, the compressed reciprocal space for higher energies allows for the observation of more diffraction spots per shot, improving the performance of the orientation refinement and generally making more data available. As of now, the impact of systematic errors such as absorption and extinction on the structure remain buried under the larger errors introduced by the partiality correction and the inter-shot scaling. Again, the application of a high energy XFEL will minimize systematic errors, facilitate more accurate structures and is expected to enable investigations of excited states and reaction intermediate chemistry.

References:

Chapman, H. N., Caleman, C. & Timneanu, N. Diffraction before destruction. Philos. Trans. R. Soc. B, 369, 1–13 (2014).

Chapman, H., Fromme, P., Barty, A. et al. Femtosecond X-ray protein nanocrystallography. Nature, 470, 73–77 (2011).

Schlichting, I. Serial femtosecond crystallography: the first five years. IUCrJ, 2, 246–255 (2015).

Li, C., Li, X., Kirian, R., et al. SPIND: a reference-based auto-indexing algorithm for sparse serial crystallography data. IUCrJ, 6, 72–84 (2019).

Støckler, L.J., Krause, L., Svane, et al. Towards pump–probe single-crystal XFEL refinements for small-unit-cell systems. IUCrJ, 10, in press (2023).

Speaker: Lennard Krause (Aarhus University)

XFEL_workshop_abstract_lkrause_2 (1).docx

14 Ultrafast atomic pair distribution function analysis

The atomic pair distribution function method is growing in popularity as an approach for studying local structure in nanomaterials, amorphous materials, moleculare materials and liquids, as well as a growing interest in the study of local symmetry breaking in bulk crystals. It is a direct measure of the local structure in the vicinity of an atom. As such, it is a very interesting representation of the structure in the context of time resolved measurements, becuase if the local bonding state or coordination of an atom is changed through photoexcitation, the PDF gives a direct measure of that change, and how the change propagates out in time from the location where it occured.
Despite this, to date there has been very little work in measuring ultrafast PDFs (ufPDFs). The reasons are technological rather than scientific. First, the resolution of the PDF in real space is directly determined by the measured range in momentum, Q. To get quantitatively reliable PDF high Qmax values of greater than 20 inv. angstroms are required, and this requires good fluxes of short wavelength x-rays (> 20 keV) to be used. Second, it is required to measure this wide range of reciprocal space quantitatively with low backgrounds and linear detector response. These limitations are now being addressed with latest generation large area 2D detectors and the developing of hard-x-ray free electron lasers.
I will describe the PDF and how it could, in principle, be used in an ultrafast time resolved context. I will then describe our recent attempt to obtain moderate resolution, quantitatively reliable, PDFs in an ultrafast PDF experiment at LCLS at SLAC. The initial results are very promising, which opens the door to much more extensive quantitative time resolved local structural studies.

Speaker: Simon Billinge (Columbia University)

15 Panel discussion and conclusions

Thursday, 19 January

Dynamics of functional materials: Plenary Session

16 Introduction

17 Glass formation in phase-change materials: The impact of a liquid-liquid transition

Glasses are formed when liquids are cooled fast enough and far enough [1]. Both criteria must be fulfilled to avoid crystallization during cooling, because thermodynamically, the crystalline state is always favorable. Therefore, thermodynamics alone cannot explain glass formation and the limiting cooling parameters are determined by the kinetic properties of a supercooled liquid. That is why glass formation is often referred to as the “freezing-in” of a disordered liquid.
The underlying physical property of the supercooled liquid is the atomic diffusivity, whose temperature dependence varies greatly between different types materials. Pure fcc metals like copper crystallize even during rapid quenching due to a high diffusivity over a wide temperature range of supercooling that is only accessible in molecular dynamics simulations [2]. Several oxides, such as SiO2, are good glass formers and have a strongly temperature-dependent diffusivity, which enables glass formation even during slow cooling [3]. An intermediate behavior is observed in phase-change materials (PCMs), which are used in non-volatile electronic and optical memory devices [4]. The diffusivity of a common phase-change material, AgIn:(Sb2Te) in the moderate supercooling regime is high, but reduces rapidly below a certain temperature [5]–[7]. This behavior has previously been explained based on empirical models and is commonly referred to as liquid-liquid transition.
By using femtosecond X-ray diffraction, we have observed a structural change around this transition in the PCMs AgIn:(Sb2Te) and Ge15Sb85 [8]. The structural information indicates that a Peierls-like atomic distortion is formed below the transition. A structural order parameter is found to correlate with the activation energy of diffusivity, which establishes for three PCMs and related materials a relationship between kinetics and atomic structure. Ab-initio molecular dynamics simulations provide further insight into the mechanism and reveal the increase of covalency in the low-temperature state.
However, the magnitude of the distortion could not be quantified experimentally, due to the low momentum transfer of the X-ray scattering experiment. High photon energy FEL radiation provides an ideal means of investigating the disordered structure of these supercooled liquids by means of pair distribution function analysis. These states of matter cannot be prepared repetitively and require a single shot structure-determination. Liquid-liquid transitions were reported also for several other supercooled liquids and many of them exist only on the sub-nanosecond timescale before crystallization set in. Furthermore, the high photon energy will bring more elements in reach for anomalous scattering techniques, which is beneficial for the investigation of multi-component materials.
[1] I. Gutzow and J. Schmelzer, The Vitreous State. Springer, 1995.
[2] H.-J. Lee, Y. Qi, A. Strachan, T. Cagin, W. A. Goddard, and W. L. Johnson, “Molecular Dynamics Simulations of Supercooled Liquid Metals and Glasses,” MRS Proceedings, vol. 644, p. L2.3, Mar. 2000, doi: 10.1557/PROC-644-L2.3.
[3] R. H. Doremus, “Viscosity of silica,” J Appl Phys, vol. 92, no. 12, pp. 7619–7629, Dec. 2002, doi: 10.1063/1.1515132.
[4] M. Wuttig and N. Yamada, “Phase-change materials for rewriteable data storage,” Nat Mater, vol. 6, no. 11, pp. 824–832, 2007.
[5] J. Kalb, M. Wuttig, and F. Spaepen, “Calorimetric measurements of structural relaxation and glass transition temperatures in sputtered films of amorphous Te alloys used for phase change recording,” J Mater Res, vol. 22, no. 3, pp. 748–754, 2007, doi: 10.1557/JMR.2007.0103.
[6] M. Salinga et al., “Measurement of crystal growth velocity in a melt-quenched phase-change material.,” Nat Commun, vol. 4, p. 2371, 2013, doi: 10.1038/ncomms3371.
[7] J. Orava, H. Weber, I. Kaban, and A. L. Greer, “Viscosity of liquid Ag–In–Sb–Te: Evidence of a fragile-to-strong crossover,” J Chem Phys, vol. 144, no. 19, p. 194503, 2016, doi: 10.1063/1.4949526.
[8] P. Zalden et al., “Femtosecond x-ray diffraction reveals a liquid–liquid phase transition in phase-change materials,” Science (1979), vol. 364, no. 6445, 2019, doi: 10.1126/science.aaw1773.

Speaker: Peter Zalden (Eur.XFEL (European XFEL))

diffus_mat.png

18 Ultrafast probing of non-equilibrium melting and solidification of metals

Due to a lack of relevant experimental data, the physical mechanisms of non-equilibrium melting and solidification (crystallization or vitrification) of metals are not fully understood. Conventional structural probes remain useless for direct observations of those transitions as they occur on an ultrashort time scale, usually from pico- to nanoseconds. As a result, their current understanding is incomplete and based mainly on theoretical modeling. Optical-pump X-ray free-electron laser probe technique is a unique method that allows tracing the structural pathway of the system through its metastable, transient states. In this approach, a thin metallic film is heated at $10 ^{14}$ K/s by an ultrashort laser pulse and cools down extremely rapidly (up to $10 ^{12}$ K/s) by dissipation of heat into a substrate. The state of the sample is probed during the heating and cooling ramps by an X-ray pulse, for which the X-ray diffraction (XRD) pattern is recorded at delay times ranging from sub-picosecond after the optical excitation. In the XRD pattern, the amount of structural information about the system is determined by the available range of the momentum transfer $q$, which scales with the energy of the incident photons. The availability of very hard X-ray pulses opens new opportunities both in terms of accessibility of high-$q$ Bragg diffraction peaks (required to determine the temperature and the strain of the crystalline lattice) and for total scattering and X-ray Pair Distribution Function (PDF) analysis of the liquid/glassy state. This talk presents selected experimental results on non-equilibrium melting and solidification of metals, illustrating the advance in knowledge provided by very hard X-rays and a possible scientific impact in the field.

Speaker: Jerzy Antonowicz (Warsaw University of Technology)

19 Probing foundational to functional behaviors in quantum materials with very hard XFEL radiation

Very hard XFEL radiation will enable a diversity of scattering studies of fundamental and functional behavior of quantum materials. With extreme pulsed magnetic fields (PMF) one may create novel electronic states, activate functional properties, and trigger non-equilibrium behavior, all of which can be probed by hard XFEL radiation. Competing charge and/or spin order in high-temperature superconductors (HTS), novel charge density waves that breaks time-reversal symmetry, piezo-magnetism, and anisotropy and vortices in superconductors are some exemplary cases. Judicious use of diffraction to reveal fundamental anisotropy constants and to understand functional and/or dynamical behavior of trapped vortices in HTS are discussed in some detail. A highly desirable functional application of bulk HTS requires trapping vortices introduced via PMF, an active area of research that may benefit by leveraging very hard XFEL radiation.

Speaker: Zahir Islam (Argonne National Laboratory)

10:15 Break

20 Understanding functionality in molecular photo-catalysis with high-energy XFELs

A key aspect of molecular (photo-) catalysis is to optimize how much of the input energy is useful towards forming the desired photoproducts. For rational design of novel catalysts it is therefore of high importance to be able to determine how the input energy is re-distributed on internal and external Degrees of Freedom such as vibrational excitations and energy loss to the surroundings. Using the well-studied Pt2POP4 and related transition metal systems as cases, this talk will address how very hard X-rays with femtosecond time resolution can enable detailed mapping of the flow of energy from the initially well-defined vibrational (wave packet) excitations, through inter-system crossings and couplings to the environment to the final and hopefully energy-rich catalytically active state.

Speaker: Kristoffer Haldrup (Technical University of Denmark, Physics Department)

21 Multi-scale approach of ultrafast photoinduced phase transitions in multi-functional materials exhibiting coupled electronic bistability and symmetry-breaking

Modern ultrafast technologies have opened new perspectives in controlling bistable magnetic materials, where light can be used to switch between different phases and thus different properties [1]. Ultrafast photo-switching within bistability regimes indeed promises enhanced control of bistability down to ultrashort timescales.

Among the available bistable materials, Prussian Blue Analogues (PBAs) are cyano-bridged bimetallic compounds with a phase transition based on a charge transfer between two stable states of different spin [2]. Moreover, the electronic charge transfer is coupled to symmetry breaking and large volume change, leading to a wide bistability hysteresis [3].

Monitoring how electronic states and symmetry reorganize and couple to give rise to functions is a real challenge. We will illustrate this by showing how to follow the multiscale dynamics of the photoinduced phase transition within the thermal hysteresis of RbMnFe PBA micro-crystals [4,5]. This was made possible by developing a new streaming crystallography method for time-resolved X-ray diffraction studies of non-reversible phenomena [5].

These results open a broad field of dynamical studies for photo-switching in bistable materials through ultrafast crystallography and X-ray spectroscopies, with scientific opportunities to extend such studies towards very Hard XFEL Radiation.

1. O. Sato, Nat. Chem. 8(7), 644-656 (2016)
2. H. Tokoro et al., Chem. Mater. 20, 423-428 (2008)
3. G. Azzolina et al., Phys. Rev. B, 102, 134104 (2020)
4. G. Azzolina et al., Eur. J. Inorg. Chem. 2019, 3142-3147 (2019)
5. G. Azzolina et al., J. Mater. Chem. C 9, 6773 (2021)

Speaker: Eric Collet (Univ. Rennes, CNRS, IPR, DYNACOM IRL2015 University of Tokyo)

22 Panel discussion and conclusions

23 Group Photo

24 Lunch break in the DESY canteen

Techniques and instrumentation: Plenary Session

25 Introduction

26 Scientific Opportunities with High-Energy Mössbauer Transitions

Since its inception in 1985 by Gerdau and coworkers at the storage ring DORIS (DESY, Hamburg), the excitation of Mössbauer transitions with x-rays from accelerator-driven sources became a widely used technique in many scientific disciplines at hard-x-ray synchrotrons worldwide, and recently also at XFEL sources.

So far, however, the method was focussed on Mössbauer isotopes with transition energies below 40 keV, mainly due to limited spectral flux at existing synchrotron radiation sources and the reduced time-resolved detection efficiency at high x-ray energies.

Notwithstanding of these circumstance there are a multitude of Mössbauer isotopes with resonance energies above 40 keV that are scientifically highly interesting. Examples are $^{61}$Ni at 67 keV for its relevance in biological functions and $^{193}$Ir at 73 keV for its role in correlated materials, to name a few.

The availability of XFEL radiation at these energies would open new scientific opportunities, of which I will illuminate some interesting applications in this presentation.

Speaker: Prof. Ralf Röhlsberger (Helmholtz Institut Jena)

27 MHz radioscopy using hard synchrotron radiation: instrumentation and applications

The use of polychromatic hard synchrotron radiation from insertion devices of high-energy storage rings such as The European Synchrotron - ESRF (France) or the Advanced Photon Source (USA) enables radioscopy with MHz repetition rates and nanosecond exposure time. Thanks to the availability of ultra-high speed cameras as well as highly dense scintillator materials with high light yield and short afterglow, individual X-ray flashes originating each from a single electron bunch in the storage ring can be isolated by indirect X-ray imaging detectors. This frequently termed single-bunch imaging approach allows for working with an effective exposure time in the order of 100 ps, i.e. several orders of magnitude shorter than the integration window of the detector applied. Together with the so-called timing modes, where commonly highly populated electron bunches are stored, synchrotron-based single-bunch imaging offers sufficient image contrast and signal-to-noise ratio to track ultra-fast phenomena in dense samples in combination with sensitive X-ray phase contrast modes. Recent examples covered in this presentation include cavity collapse by impact, laser-induced compression waves, shock waves induced by energetic materials or wire explosion, fracture by shear-stress loading as well as brittle facture in wafers.
The successful study of such processes requires high-level X-ray imaging instrumentation as well as sophisticated sample environments which include frequently medium-scale gas launchers, ns-pulsed lasers, or Split-Hopkinson pressure bars. At the ESRF beamline ID19, those platforms are made available via a new access mode, the so-called Block Allocation Group (BAG): a community-driven approach where besides the instrumentation the facility also offers regular access to beamtime for a consortium that internally decides on the experiments to be carried out and studies to be followed.
In the frame of this presentation, we shall outline the established capabilities at synchrotron light sources. Consequently, the need for very hard X-ray FEL radiation can be introduced, i.e. in order to go substantially beyond the current state-of-the-art single-bunch X-ray imaging.

Speaker: Alexander Rack (European Synchrotron Radiation Facility)

15:25 Break

28 Inelastic x-ray scattering

Inelastic x-ray scattering at very high energies provides opportunities at least in two different new fields at European XFEL: Compton scattering spectroscopy for momentum density studies, and scattering-based imaging. I will discuss both: 1) The principles of Compton scattering spetroscopy and how it can be used in both fundamental research of electron momentum densities and in applied research including studies of batteries and other complex systems; 2) Single-shot x-ray imaging based on x-ray optical concepts of focusing crystals and observation of wide-angle dark-field (scattered) photons.

Speaker: Simo Huotari (Eur.UPEX)

29 Opportunities for Sustainable Metallurgy with High-Energy XFEL Microscopy

Metallurgy has enabled technological innovation for millennia, but scientific uncertainties still limit progress in shifting the processes to sustainable alternatives at scale. Of the ~30% of global emissions that originate from our supply chain, >10% of those emissions originate from complex metallurgical processes understood predominantly at the process scale. From ore extraction to forging or 3D printing technologies, we require fundamental models to connect scientific advances to new and scalable engineering strategies. Across these fields, however, unanswered questions persist due to missing experimental techniques to resolve them deep inside opaque and high-Z materials. In this talk, I will introduce challenges in sustainable metallurgical engineering and discuss avenues in which advanced microscopy with high-energy X-rays can enable transformative changes in our understanding and control of these new systems.

Speaker: Prof. Leora Dresselhaus-Marais (Stanford University)

30 Enhancing capabilities of XFEL scattering techniques by short-wavelength radiation

This talk reviews current limitations of XFEL scattering techniques and discusses potential impact of the very hard XFEL pulses on the structure determination, while presenting relevant experimental data taken at SACLA.

The first half of this talk reviews the XFEL-induced damage (sample heating [1,2] and ultrafast electron excitations [3,4]), which is inevitable when using focused X-ray pulses produced by current XFEL machines. The short-wavelength radiation relaxes such radiation damage and thereby enhances the capabilities of existing XFEL scattering techniques, such as ultrafast X-ray photon correlation spectroscopy [2] and high-resolution serial femtosecond crystallography [5].

In the remaining part of the talk, I would propose a few tricky experiments using very hard XFEL pulses, including structure determination of materials under high magnetic fields (more than 100 T) [6] and nonlinear diffraction techniques [7] for material characterization and a basis for X-ray pulse shaping and compression.

[1] F. Lehmkühler et al., PNAS 117, 24110 (2020).
[2] Y. Shinohara et al., Nature Commun. 11, 6213 (2020).
[3] N. Medvedev and B. Ziaja, Sci. Rep. 8, 5284 (2018).
[4] I. Inoue et al., Phys. Rev. Lett. 126, 117403 (2021).
[5] K. Takaba et al., accepted to Nature Chem. (ChemRxiv 10.26432/chemxiv-2021-jvbfl).
[6] A. Ikeda et al., Appl. Phys. Lett. 120, 142403 (2022).
[7] I. Inoue, B. Ziaja et al., in preparation.

Speaker: Ichiro Inoue (RIKEN SPring-8 Center)

31 Panel discussion and conclusions

Poster Session

book-of-abstracts.pdf

32 Towards a superconducting undulator afterburner for the European XFEL

We propose to develop, characterize and operate a superconducting undulator (SCU) afterburner consisting of 5 undulator modules (1 module = 2 times SCU coil of 2 m length and 1 phase shifter) at the SASE2 hard X-ray beamline of European XFEL. This afterburner has the potential to produce an output of more than 1010 ph/pulse at photon energies above 30 keV. The project is divided into the production of a pre-series prototype module and a small-series production of 5 modules. Central goals of this R&D activity are: the demonstration of the functionality of SCUs at a X-ray FEL, the set up of the needed infrastructure to characterize and operate SCUs, the industrialization of such undulators and the reduction of the price per module

Speaker: Dr Harald Sinn (European XFEL)

33 Ultrafast Pair Distribution Function Measurements of Local Structural Dynamics in CuIr2S4

The Pair Distribution Function (PDF) method interprets Total Scattering data in real space [1]. This distinguishes local structure from the long-range average using information contained within diffuse scattering. xFEL facilities provide the potential to apply this tool to pump-probe experiments and local structural dynamics on the native (sub-)picosecond response timescale of a material.

We show an application of ultra-fast pump-probe PDF (uf-PDF) to CuIr2S4. Below 226 K, the regular Ir sub-lattice of this material forms Ir-Ir dimers with long range order [2][3]. Using uf-PDF, a decrease in dimerisation is seen within 1 ps of optical pumping. The local (< 1 unit cell) and long-range structures display distinct dynamical behaviours with the long-range structure continuing to evolve over 10s of ps as the pumped phase orders over increasing distances.

Speaker: Jack Griffiths (Brookhaven National Laboratory)

34 Ultrafast X-ray Diffraction and Scattering at the Femtosecond X-ray Experiment (FXE) Instrument at the EuropeanXFEL: present status and future perspectives

Time-resolved X-ray methods are widely used for monitoring time-resolved electronic and structural dynamics over the course of photochemical reactions. Since fundamental processes in physics, chemistry and biology occur in ultrashort time range (from 10e-12 to 10e-15 s), X-ray free electrons lasers (XFELs) development received much more attention in the last ten years. Several experiments have successfully demonstrated that this new generation of light sources provides unprecedented insight into structural and electronic dynamics occurring during photo-induced reactions in various condensed-matter systems [1-2]. The EuXFEL allows to investigate these types of mechanisms thanks to the extremely brilliant (>10e+12 photons pulse-1), ultra-short pulses (<100 fs), transversely coherent X-ray radiation, high repetition rate of up to 4.5 MHz, and extreme focusing(<10 um).
In this contribution, we present an overview of the present status and future perspectives of time-resolved diffraction and scattering techniques at the FXE beamline in EuXFEL. The instrument uses femtosecond optical laser pulses to pump the samples while the ultrafast X-ray FEL pulses probe their dynamical evolution in the so-called pump-probe method. The FXE instrument enables a femtosecond temporal resolution down to about 115 fs FWHM [4]. One unique scientific capability of FXE is to study ultrafast dynamics with various X-ray methods simultaneously in the photon energy range from 5 to 20 keV [3-4]. X-ray diffraction and scattering experiments on liquid and solid systems have been achieved at FXE[3]. For instance, ultrafast photochemistry studies in solution phase are performed by combining the wavelength-dispersive 16-crystal von HamosX-ray emission spectrometer (XES) and X-ray solution scattering (XSS) recorded the Large Pixel Detector (LPD) [5-6]. Starting with non-resonant simultaneous Ka and Kb XES on Fe complexes [7-9] the capability was extended to a variety of other metal complexes including Co-, Ni- and Cr-based systems. The FXE beamline have also achieved successful sold-state experiments, including XES on thin films, single-crystal XRD with the Jungfrau detector motion, and polycrystalline scattering with the LPD.
The next step at the FXE beamline is to enable further solid-state experiments. In this perspective, the XTRAS project (ultrafast X-ray crystallography with diverse sAmple delivery) will be developed to provide femtosecond atomic “movies” of molecular crystals by means of single crystal XRD experiments and to reconstruct ultrafast intermediate state structures. The objective is to upgrade the existing vacuum chamber, and thereby provide rotation XRD, simultaneous XRD and XES, and cryogenic conditions for experiments requiring diverse sample delivery methods.

References
[1] Abela, R. et al. Struct. Dyn. 4, 061602 (2017).
[2] Chergui, M. & Collet, E. Chem. Rev. 117, 11025–11065 (2017).
[3] Galler, A. et al. J. Synchrotron Rad. 26, 1432–1447 (2019).
[4] Khakhulin, D. et al. Appl. Sci. 10, 995 (2020).
[5] Hart, M. et al. IEEE NSS/MIC 534 (2012).
[6] Veale, M. et al. JINST 12, P12003 (2017).[7] Bacellar, C. et al. PNAS 117, 21914-21920 (2020).
[7] Bacellar, C. et al. PNAS 117, 21914-21920 (2020).
[8] Naumova, M. et al. J. Phys. Chem. Lett. 11, 6, 2133–2141 (2020).
[9] Naumova, M. et al. J. Chem. Phys. 152, 214301 (2020).

Speaker: Doriana Vinci (Eur.XFEL (European XFEL))

35 The Structure of USP7 at Ambient Temperature by Using X-ray Crystallography

The Structure of USP7 at Ambient Temperature by Using X-ray Crystallography

Nowadays cancer is a serious problem that doesn’t have very efficient treatment approaches. According to the world health organization (WHO) 10 million people died because of cancer in 2020. [1] Some mutations in DNA cause cancer and these cancer cells hide from cell cycle regulators and avoid cell death called apoptosis by using many methods. However, once cancer cells can undergo apoptosis and prevent tumor development, cancer processes can get slower or regress. P53 is a very crucial gene to control the cell cycle and apoptosis mechanism. Ubiquitination of P53 lead to its degradation.[1][2][3][4] The decrease in the level of p53 expression in the cell due to the degradation, and apoptosis decreases in direct proportion. P53 has a regulatory relationship with USP7 protein (Ubiquitin-specific-processing protease 7). USP7 mainly functions about deubiquitinating like deubiquitinating the P53. In other words, USP7 help to increase in P53 expression level and reduce cancer development. Researchers show how usp7 is important for cancer treatment.[2][3][4] To better understand usp7 and its functions, we need to observe its ambient structure. According to achieve this structure, USP7 protein expression was obtained at 18 °C with 5uL 0.4M IPTG per 150 mL. Then we going to crystalize them with 3500 different commercial conditions and check their structure with Turkish DeLight. [5] Turkish DeLight is a very important X-ray crystallography device which is sending the X-ray photons through the crystal plate and collecting the diffraction data with a detector from behind the crystal plate for 1 min and 45 sec (5 secs/frame) while oscillation occurs. Finally, data will be processed with CrysAlisPro, and the structure determined with Phenix and COOT. On the other hand, using x-ray crystallography has a significant disadvantage. X-ray photons cause radiation damage which affects the protein structure. [5]

References:
[1] Ferlay J, Ervik M, Lam F, Colombet M, Mery L, Piñeros M, et al. Global Cancer Observatory: Cancer Today. Lyon: International Agency for Research on Cancer; 2020 (https://gco.iarc.fr/today, accessed February 2021).
[2] Qi SM, Cheng G, Cheng XD, Xu Z, Xu B, Zhang WD, Qin JJ. Targeting USP7-Mediated Deubiquitination of MDM2/MDMX-p53 Pathway for Cancer Therapy: Are We There Yet? Front Cell Dev Biol. 2020 Apr 2;8:233. doi: 10.3389/fcell.2020.00233. PMID: 32300595; PMCID: PMC7142254.
[3] Wang Z, Kang W, You Y, Pang J, Ren H, Suo Z, Liu H, Zheng Y. USP7: Novel Drug Target in Cancer Therapy. Front Pharmacol. 2019 Apr 30;10:427. doi: 10.3389/fphar.2019.00427. PMID: 31114498; PMCID: PMC6502913.
[4] O'Dowd CR, Helm MD, Rountree JSS, Flasz JT, Arkoudis E, Miel H, Hewitt PR, Jordan L, Barker O, Hughes C, Rozycka E, Cassidy E, McClelland K, Odrzywol E, Page N, Feutren-Burton S, Dvorkin S, Gavory G, Harrison T. Identification and Structure-Guided Development of Pyrimidinone Based USP7 Inhibitors. ACS Med Chem Lett. 2018 Feb 21;9(3):238-243. doi: 10.1021/acsmedchemlett.7b00512. PMID: 29541367; PMCID: PMC5846043.
[5] Gul, M., Ayan, E., Destan, E., Johnson, J., Shafiei, A., Kepceoglu, A., Yilmaz, M., Ertem, F., Yapici, ., Tosun, B., Baldir, N., Tokay, N., Nergiz, Z., Karakadio glu, G., Paydos, S., Kulakman, C., Ferah, C., Güven, ., Atalay, N., Akcan, E., Cetinok, H., Arslan, N., \c Sabano\u glu, K., A\c sci, B., Tavli, S., Gümüsbo\u ga, H., Altunta\c s, S., Otsuka, M., Fujita, M., Tekin, ., \c Cift\c ci, H., Durda\u gi, S., Karaca, E., Kaplan Türköz, B., Kabasakal, B., Kati, A., & DeMirci, H. (2022). Rapid and High-Resolution Ambient Temperature Structure Determination at Turkish Light Source. bioRxiv.

Speaker: Bengisu Aşcı (myself)

Ubp7 abstractt.pdf

36 Structural Studies of Traf6 Inhibition

Traf6 is a protein which affects NF-KB mediated transcription, hence it has a role in proliferation, differentiation, apoptosis and other cellular processes. Recent research has shown that, various forms of pancreatic cancer is related to Traf6 function, making the protein a good therapeutic target. A novel dithiol agent named SN1 shows good promise as a Traf6 inhibitor, as it can reduce the disulfide bonds formed at multiple zinc fingers of the target protein. In this study we are trying to find the molecular mechanism with which the SN1 interacts with Traf6.

Speakers: Ömür Güven (Koc University), Ms İlkin Yapici (Koc University)

Abstract.docx

37 Accuracy and limitations of XFEL structure determination inferred from X-ray pump X-ray probe studies

Understanding intense XFEL interaction with matter is essential not only because of fundamental interest but also for interpreting experimental results. This presentation reviews recent experimental studies on intense x-ray interaction with matter using unique operation modes at SACLA (twin XFEL mode [1] and self-seeding mode [2]).
In particular, I will focus on XFEL-induced femtosecond structural and electronic changes in crystalline materials [3-6] revealed by X-ray pump X-ray probe techniques. Based on the experimental results, I will discuss the accuracy and limitations of structure determination with intense XFEL pulses.
[1] T. Hara et al., Nature Commun. 4, 2919 (2013).
[2] I. Inoue et al., Nature Photon. 13, 319 (2019).
[3] I. Inoue et al., PNAS 113, 1492 (2016).
[4] I. Inoue et al., PRL 126, 117403 (2021).
[5] I. Inoue et al., PRL 128, 223204 (2022).
[6] I. Inoue, J. Yamada, B. Ziaja et al., in preparation.

Speaker: Ichiro Inoue (RIKEN)

38 An ambient Temperature crystal structure of bacterial CyaY Determined at Turkish Light Source

Abstract

The iron-sulfur (Fe-S) cluster assembly is an essential mechanism for sufficing cellular needs for the Iron sulfur clusters, the ancient small protein cofactors, found in various organisms. The iron-sulfur cluster assembly machinary is known to be correlated with diverse cellular functions including electron transfer, gene expression, regulation, nitrogen fixation, RNA modification , DNA repair and replication. Iron sulfur cluster assembly is accomplished by highly conserved systems existing both in prokaryotes and eukaryotes. In prokaryotes the most general system is ISC, encoded by isc operon (IscR, IscS, IscU, HscB, HscA, , IscA, ferredoxin and CyaY) that have eukaryotic homologs. CyaY, bacterial ortholog of eukaryotic mitochondrial frataxin, thought to have a role in iron sulfur cluster assembly as an iron supplier. In addition, mutation in Frataxin, a mitochondrial iron-binding protein, caused Friedreich's ataxia a progressive neurodegenerative disorder, therefore CyaY has attracted attention due to its essential role. Here we present the first ambient temperature crystal structure of CyaY protein from Escherichia coli obtained using the home source Rigaku Oxford Diffraction XtaLAB Synergy-S diffractometer. This study provides valuable insights to better understand the dynamic characteristics of the protein in near-physiological conditions which may not have been noticed in previous cryogenic studies.

Speaker: alaleh shafiei (PhD student)

Abstract.docx

39 Swedish Materials Science Beamline (SMS) at PETRA III: In-line branch (P21.2)

The Swedish Materials Science beamline (SMS) at PETRA III is dedicated to the exploitation of high energy synchrotron radiation (40-150 keV) for materials science applications, the key features of high energy X-rays being penetration power and compression of reciprocal space onto area detectors. The in-line branch (P21.2) has been designed for the investigation of both bulk materials and surfaces by a combination of complementary contrast mechanisms (WAXS, SAXS, Imaging) and variable beam sizes from micro- to millimeters. Typical scientific areas include mechanical properties of engineering materials, electro-chemistry, and catalysis. The pertinent beamline instrumentation is described and performance parameters are presented.

Speaker: Ulrich Lienert (DESY)

40 Near-Physiological-Temperature Serial Femtosecond X-ray Crystallography Reveals Novel Conformations of SARS-CoV-2 Main Protease Active Site

Radiation damage is one of the major limitations of x-ray crystallography. XFELs provide ultrafast and ultrabright X-ray pulses allowing data collection without secondary radiation damage at ambient temperature. Here, we determined the crystal structure of Severe Acute Respiratory Syndrome CoronaVirus-2 main protease by serial femtosecond x-ray crystallography. To compare the structural changes caused by radiation damage, we calculated the radiation damage on our structure and compared it to other main protease structures that are obtained from different x-ray sources. Our work not only shows the effect of radiation damage but will also provide structural dynamics of the main protease for drug repurposing and structure-based drug design studies against SARS-CoV-2.

Speaker: Fatma Betul Ertem (Koc University)

41 High Energy Laue X-ray Emission Spectrometer at the European XFEL

X-ray emission spectroscopy (XES) is a powerful tool for electronic structure characterization, it has been widely used in the study of 3d transition elements, while the K-edge XES spectra of 4d elements were rarely reported [1], even though they are greatly important for phase transition, photocatalyst, biology, geochemistry and etc. One of the main reasons for this is that the K emission lines of 4d elements are usually larger than 16 keV [2] and the standard XES spectrometers (Johann and von Hamos) based on Bragg analyzers quickly loose efficiency when the photon energy is larger than 15 keV. Moreover, the fine structures of X-ray absorption spectroscopy for high-Z elements at high X-ray energies will be strongly submerged by the large core-hole lifetime broadening (>10 eV when the absorption edge>30 keV), the high energy resolution fluorescence detected (HERFD) XAS [3] will be essential for the core-level spectroscopies for very hard X-ray, wherein the high efficiency emission analyzers become to be necessary.
The newly Laue analyzer was designed by FXE group of European XFEL and recently tested at SuperXAS of SLS(~1010 phs/sec). The analyzer has open window of 8×3 cm2, radius of 1.5 m, thickness of 0.25 mm and an asymmetric angle of 2.5° for improving the efficiency, the static nor dynamic bender was chosen for more easy and productive commissioning. We have investigated the possibility of operating off of the Rowland circle to explore the dispersive capabilities, the analyzer can disperse fluorescence X-ray spatially according to its energy, and an algorithm to convert the emission image to spectrum was developed. In this arrangement, as shown in the Fig. 1, the valence to core (VtC) spectra for niobium (with K edge of 19 keV) samples can be visible ~10 mins at SuperXAS beamline. A resolution of 6.7 eV has been realized with the beam size of ~100 um, better resolution of ~2.5 eV is expected when reducing the beam size to ~20 um.

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

Abstract_VeryHardXFEL.pdf

42 Enhanced Metallophilicity in Stimuli-responsive Dimer Complexes using Hard X-ray WAXS and HERFD-XAS

We are investigating the formation of metallophilic bonds in luminescent stimuli-responsive compounds based on ligand-supported Au(I)/Ag(I)/Cu(I) complexes upon electronic transition to the emissive excited state. Combining pump-probe X-ray absorption spectroscopy with high energy resolution (HERFD-XAS) and wide-angle X-ray scattering (WAXS) in the solution we can visualize the local redistribution of electron density as well as the drastic changes in molecular structure when a weak metallophilic bond is formed in the triplet excited state.

Speaker: Sharmistha Paul Dutta (Eur.XFEL (European XFEL))

43 XFEL MHz imaging of ultrasonic exfoliation of 2D functional materials

Ultrasonic liquid phase exfoliation has been identified as a promising processing route for manufacturing 2D functional materials in large scale. The ultrasonic cavitation bubble implosion plays a critical role in enabling 2D layer exfoliation. However, due to the highly transient implosion process occurring at µm length and sub-µs time scale, many fundamental issues in this process are either not fully understood or not fully quantified. It is due to mainly the difficulty in directly observing the dynamic phenomena in-situ and in real time operando conditions.

Here, we report our very recent experimental results of using the MHz imaging capability available at the EU X-ray free electron laser facility. The unique world leading capability allows us to observe directly the interactions of liquid, bubble and solid phases never been reported before, providing essential data for understanding the sub-µs scale microfluidic dynamics and how the shock wave at bubble implosion is able to exfoliate the bulk graphite into multiple layer 2D sheet materials.

Speaker: Prof. Jiawei Mi (University of Hull)

44 Considerations for CRL pre-focusing optics at the MID instrument in hard X-ray range above 30 keV

The concept of high-harmonic lasing at X-ray Free-Electron Laser (XFEL) facilities [1] opens new perspectives of generating ultrashort SASE pulses in ultrahard X-ray range up to 100 keV. The European XFEL (EuXFEL) facility is the worldwide unique hard XFEL based on superconducting accelerator operating at an electron energy of up to 17.5 GeV and producing electron bunches at MHz repetition rates distributed to three SASE undulator sections [2]. The EuXFEL linac parameters provide beneficial conditions for high-harmonic lasing as confirmed by simulations [1] and proof-of-principle results obtained at soft X-ray SASE-3 undulator [3]. The Materials Imaging and Dynamics (MID) instrument is located at the hard X-ray SASE-2 undulator section in a straight geometry and enables user experiments in the 5–25 keV X-ray range [4, 5]. When expanding this range to harder X-ray energies the beam transport optics specifications must be revisited. This concerns in particular the offset and distribution X-ray mirrors which block spontaneous and Bremsstrahlung radiations and transmit an XFEL beam to the endstations. MID utilizes M1 and M2 mirrors that transmit photon energies up to 67 keV using Pt-coated stripes [6, 7]. Further X-ray optics crucial for beam transport are compound refractive lenses (CRLs) [8] enabling the beam collimation and pre-focusing at the instrument. CRL-1 and CRL-2 transfocator units equipped with Be CRL stacks of various radii of curvature (ranging from 5.8 mm to 50 μm) are located in SASE-2. Photon tunnel CRLs enable a tunable range of beam sizes in a working X-ray range of the MID instrument [4, 9]. A free slot for the high-energy CRL-3 unit for extended hard X-ray range is available in the XTD6 photon tunnel [4]. This contribution considers possible options for pre-focusing CRL transfocator optics in ultrahard photon energy range based on standard Be, Al lenses, and diamond CRLs.

References
[1] E. A. Schneidmiller and M. V. Yurkov. Phys. Rev. Accel. Beams, 15, 080702 (2012).
[2] T. Tschentscher, et al. Appl. Sci. 7, 592 (2017); W. Decking, et al. Nat. Photon. 14, 391 (2020).
[3] E. Schneidmiller et al. Proc. FEL'19, Hamburg, Germany, pp. 172-175 (2019).
[4] A. Madsen, J. Hallmann, T. Roth, and G. Ansaldi (2013). XFEL.EU Technical Report TR-2013-005, pp. 1–191. European XFEL, Schenefeld, Germany.
[5] A. Madsen et al. Synchrotron Rad. 28, 637 (2021).
[6] H. Sinn, J. Gaudin, L. Samoylova, et al. (2011). XFEL.EU TR-2011-002, pp. 1–132. European XFEL, Schenefeld, Germany.
[7] M. Störmer, et al. J. Synchrotron Rad. 25, 116 (2018).
[8] B. Lengeler, C. Schroer, J. Tümmler, et al. J. Synchrotron Rad. 6, 1153 (1999).
[9] A. Zozulya et al., Proc. SPIE, 11111, 111110H (2019).

Speaker: Alexey Zozulya (Eur.XFEL (European XFEL))

45 Rapid and High Resolution Ambient Temperature Structure Determination at Turkish Light Source

Determining the high-resolution biomacromolecular structure is crucial for understanding protein function and dynamics. Serial crystallography is a new structural biology technique, but it is constrained fundamentally by the need for large samples or by the need for quick access to the scarce X-ray beamtime. The key challenge in serial crystallography continues to be obtaining a large number of sufficiently large, well-diffracting crystals while minimizing radiation damage. As an alternative, we provide the plate-reader module designed for determining the structure of biomacromolecules utilizing a 72-well Terasaki plate at a home X-ray source. We also provide the first lysozyme structure identified at ambient temperature from the Turkish Light Source (Turkish DeLight). The entire dataset, which had a resolution of 2.39 and was 100% complete, was collected in 18.5 minutes. The ambient temperature structure sheds important light on the structural dynamics of the lysozyme when combined with our earlier cryogenic structure (PDB ID: 7Y6A). Turkish DeLight offers reliable and quick analysis of biomacromolecular structure at ambient temperature with minimal radiation damage.

Speakers: Mehmet Gul (Koc University), Ms Merve Yilmaz (Koc University)

46 Ambient Temperature Structure of Large Ribosomal Subunit from Thermus Thermophilus

The introduction of ultrafast and ultrabright X-ray free electron lasers (XFELs) has allowed us to observe the structural illumination of biological macromolecules unattainable in synchrotron radiation sources at an unprecedented temporal and spatial resolution. Here we report the first near-physiological temperature structure of a large ribosomal subunit (50S) isolated from Thermus Thermophilus. Prokaryotic ribosomes are the target of more than half of known antibiotics and the large ribosomal subunit (50S) is targeted by blockbuster antibiotics such as macrolides and ketolides. 50S is one of the largest structures identified in an XFEL to date, with 3 MDa asymmetric units due to dimerization (1.5 MDa each) within the unit cell. A complete structure at 3.99 A was obtained while consuming less than 100 uL of crystal sample, at a record short beam duration of 47 minutes. In the absence of radiation damage, a higher degree of solvent presence is observed, which is crucial for the stability and functionality of the ribosome. This study demonstrates the feasibility of improving the structural understanding of the unique binding sites and structural dynamics of T. thermophilus 50S at physiological temperatures enabling us to gain more structural insights into ribosome structure and function while enhancing our ability to develop next-generation antibiotics.
Additionally, this structure serves as the starting point for future work involving the large ribosomal subunit and time-resolved serial femtosecond crystallography (tr-SFX) experiments at XFELs.

Speakers: Ms Bilge Tosun, Cahine Kulakman

47 Development New Generation of Imatinib Using Structural Biology Techniques at Ambient Temperature

Chronic myeloid leukemia (CML) is a kind of blood cancer and most CML patients have associated with a chromosomal anomaly with the BCR-ABL fusion oncogene, which occurs as a result of translocation between the Abelson murine leukemia (ABL1) gene on chromosome 9 and breakpoint cluster region (BCR) gene on chromosome 22. Imatinib mesylate is the first small molecule developed to target the BCR-ABL fusion protein. Imatinib reduces BCR-ABL activity by binding to the inactive conformation of tyrosine kinases. Despite a high response rate in CML patients with imatinib therapy, almost one-third of patients still have an inadequate response to Imatinib. In other words, due to mutations in region of Imatinib binding-pocket or other of the BCR-ABL, resistance to Imatinib has emerged in CML patients. Therefore, there have revealed need to develop a more potent new molecule with an Imatinib function. In this study, ABL kinase domain gene was purchased from Genscript Biotech. The gene was inserted to pET11a vector plasmid constract. The plasmid was transformed into E. coli, strain BL21 (Rosetta-2). Transformed E. coli were grown overnight on agar plates. The colonies were collected from agar plates and started large volume of culture in rich LB media. To be able to procure further purified protein, we were used Ni-NTA affinity chromatography. The purified protein solution was added to crystal screen conditions in Terasaki plates. Then, X-ray diffraction images were collected from the formed crystals in order to acquire the best 3D structure. These diffraction datas were collected from XtalCheck module (Rigaku Oxford Diffraction) at ambient temperature. We will have revealed the structures determined at ambient temperature and high resolution with the help of X-ray crystallography technique. Additionally, we will have re-evaluated structures and designed new target small molecule with approaching from the perspective of integrative structural biology. The results propose that may developed a new generation of imatinib that is more specific, high affinity and resistant to possible mutations to treat CML disease and improve patients’ lives.

Speaker: Gözde Karakadıoğlu Usta

48 Rapid and High Resolution Ambient Temperature Structure Determination at Turkish Light Source

Determining the high-resolution biomacromolecular structure is crucial for understanding protein function and dynamics. Serial crystallography is a new structural biology technique, but it is constrained fundamentally by the need for large samples or by the need for quick access to the scarce X-ray beamtime. The key challenge in serial crystallography continues to be obtaining a large number of sufficiently large, well-diffracting crystals while minimizing radiation damage. As an alternative, we provide the plate-reader module designed for determining the structure of biomacromolecules utilizing a 72-well Terasaki plate at a home X-ray source. We also provide the first lysozyme structure identified at ambient temperature from the Turkish Light Source (Turkish DeLight). The entire dataset, which had a resolution of 2.39 and was 100% complete, was collected in 18.5 minutes. The ambient temperature structure sheds important light on the structural dynamics of the lysozyme when combined with our earlier cryogenic structure (PDB ID: 7Y6A). Turkish DeLight offers reliable and quick analysis of biomacromolecular structure at ambient temperature with minimal radiation damage.

Speakers: Ms MERVE YILMAZ (Koc University), Mr Mehmet Gül (Koc University)

49 Structural insight into the binding mode of sisomicin derivatives and gentamicin C2b to the decoding center of the 30S ribosomal subunit

Aminoglycosides are antibiotics that cause translational misreading of mRNA by binding to the A-site in the 30S ribosomal subunit. Together with the importance of antibiotics in the clinic, there are still missing details about their binding mode and structural dynamics on the decoding center of the 30S ribosomal subunit. Sisomicin is a precursor of structurally similar aminoglycoside antibiotic gentamicin and gentamicin involves five subtypes (C1, C1a, C2, C2a, C2b). Each subtype displayed differences in ototoxicity in vitro. Within them, gentamicin C2b is detected as less ototoxic compared to sisomicin. Although sisomicin is a highly effective broad-spectrum antibiotic for the treatment of bacterial infections, the side effects in terms of oto- and nephro- toxicity play a critical role during the treatment. Previously, it was determined that modifications on the sisomicin lowered ototoxicity with variable effects on antimicrobial activity. Here, revealing the crystal structure of 30S ribosomal subunit in complex with sisomicin derivatives and assessing ribosomal interaction at atomic-level of resolution will provide invaluable information for future studies. Additionally, comparison of binding modes with 30S ribosomal subunit in complex with gentamicin C2b will highlight the structural dynamics of the decoding region.

Speaker: Ebru Destan

50 The "Shock" Beamtime Allocation Group at beamline ID19 of the ESRF

4$^{th}$ generation high-energy synchrotron photon sources offer unprecedented capabilities of probing matter during transient dynamics at high spatio-temporal scales using hard X-rays. The combination of high brilliance, short bunch duration (down to 60~ps) and high-energy of the extremely brilliant source at ESRF-EBS$^1$ opens the door of studying materials under extreme events of shock and high-strain rate combined to in-situ subsurface ultra-high speed X-ray radioscopy measurements at relevant scales$^3$. The recent establishment of new access modes$^2$, such as beamline allocation groups (BAG), aim at building a collaborative community and providing regular access to the shared pool of cutting-edge installations. The so-called "Shock" BAG brings together experts in shock physics and dynamic behaviour of materials, building upon the recently installed instrumentation such as Split-Hopkinson Pressure bar (SHPB), single stage gas launcher, ns-pulsed laser shock and pulsed power-driver as well as a chamber compatible with energetic materials which allow studying matter under a plethora of extreme scenarios. The community-driven scientific topics tackle the growing demand of developing novel engineering materials with the ability to sustain the high strain rate and shock as well as fundamental physical questions of material phase change and instabilities of shocked matter. Recently, the first experimental campaigns have been successfully conducted using the SHPB and gas gun installations, with applications ranging from reproducing earthquake scenarios and dynamic fracture of novel composite and additively manufactured materials, to shock propagation and dynamically driven cavity collapse, of which selected examples will be showcased.

$^1$ P. Raimondi, (2016). ESRF-EBS: The Extremely Brilliant Source Project, Synchrotron Radiation News, 29(6), 8-15.
$^2$ J. McCarthy, H. Reichert, (2022). ESRF Prepares New User Access Mode, Synchrotron Radiation News, 35(2), 52-54.
$^3$ M. Olbinado, X. Just, J-L Gelet, P. Lhuissier, M. Scheel, et al. (2017). MHz frame rate hard X-ray phase-contrast imaging using synchrotron radiation, Optics Express, 25(12), 13857-13871.

Speaker: Bratislav Lukic (ESRF)

Abstract_XFEL_ShockBAG_vf3.pdf

51 Towards Femtosecond Structural Dynamics of Small Unit Cell Systems and Non-Crystalline Materials

In recent years, molecular dynamics of macromolecules has benefitted immensely from the femtosecond timescales of X-ray Free Electron Lasers (XFELs)$\mathrm{^{[1]}}$. However, the progress for small unit cell systems has been slow. Thus, Dr. L. Krause and B. Svane have developed a data reduction pipeline for small unit cell systems, including peak hunting, indexing, integration, and post-refinement$\mathrm{^{[2]}}$. Using the pipeline, data measured on single crystals of a I4/m polymorph of $\mathrm{K}_4\mathrm{[Pt_2(P_2O_5H_2)_4]∙2H_2O}$ (PtPOP) at the SPring-8 Compact Free-Electron Laser (SACLA) have been reduced to structure factors that allow direct methods to solve the structure (R1 ~ 9.3%)$\mathrm{^{[3]}}$. Hopefully, the pipeline will allow for ultrafast structural dynamics, tracking for example the changes taking place upon photoexcitation of PtPOP.
Other structural dynamics studies that could benefit from femtosecond time resolution are the tracking of nanoparticle nucleation and growth (N&G). Pair Distribution Function (PDF) analysis is often the method of choice for following the N&G from precursor solutions$\mathrm{^{[4]}}$. Currently, the time resolution of in situ PDF studies performed at synchrotrons is on the order of ms, but many interesting processes occur on shorter timescales. Therefore, data measured at SACLA on $\mathrm{HfO_2}$ nanoparticles in a liquid jet have been used to obtain a femtosecond PDF. This PDF has been compared to in situ PDF data measured on a capillary containing a suspension of $\mathrm{HfO_2}$ nanoparticles at PETRA III, Deutsches Elektronen-Synchrotron (DESY)$\mathrm{^{[5]}}$. The SACLA PDF reproduce many of the features observed in the PETRA PDF with the same $\mathrm{Q_{max}}$-value, but a higher $\mathrm{Q_{max}}$ is required to obtain better PDFs.

References
[1] Martin-Garcia, J. M., et al., Arch. Biochem. Biophys., 2016, 602, 32-47.
[2] Svane, B., PhD thesis, Aarhus University, 2021, 79-114.
[3] Paper submitted; Støckler, L. J., et al., IUCrJ, 2022.
[4] Egami, T., and S. J. L. Billinge, ‘Underneath the Bragg peaks: structural analysis of complex materials’, Elsevier, Amsterdam, 2012.
[5] Christensen, R. S., et al., Nanoscale, 2021, 13, 12711-12719.

Speaker: Lise Joost Støckler (Aarhus University)

52 Dinner in the DESY Canteen

Friday, 20 January

High pressure, warm dense matter, electron dynamics, strong field science: Plenary Session

53 Introduction

54 Implications of High Photon Energy FELS for some areas of HED Science

There are some implications of the provision of higher photon energies at x-ray FEL facilities that are obvious: increased photon momentum allows greater exploration of reciprocal space. This is evidently important in our understanding of liquids under high dynamic pressure, where greater momentum transfer allows us to go beyond mere density measurements to provide specific information about coordination numbers and so-forth. Similar arguments could be made for shocked or dynamically compressed solids - the expansion of reciprocal space under compression automatically pushes us to desire higher photon energies. However, in this presentation, which I emphasise is a personal view, I would like to take the general argument further. A good fraction of the HED science performed at FEL facilities has been undertaken under uniaxial compression conditions. Such conditions, by definition, keep the density-length product of the target of the interest constant, but also severely limit the compressions that can be achieved. Far higher compressions (and density-length, or density-radius) conditions could be achieved in convergent geometries, which are actually the work-horses of a great deal of HED research beyond FEL facilities, but for the Science of interest at FELs have received almost no attention. I will argue in this talk that, at the same time as arguing for higher photon energies, we ought to be considering promoting novel drive systems in convergent geometries that both require and can exploit higher photon energies.

Speaker: Justin Wark (University of Oxford)

55 X-ray spectroscopy, diffraction and imaging techniques for high energy density matter enabled by very hard X-rays at XFELs

The combination of X-ray free electron lasers with energetic and intense pulsed lasers has started to revolutionize the experimental investigation of matter at high energy densities comparable to the interiors of planets and stars and numerous applications transiently requiring such conditions. With future sources possibly going beyond the current world record set by EuXFEL at 25 keV, new methods for characterizing matter of extreme energy density will become available. This includes very high q-range diffraction experiments for most precise characterization of the liquid structure of dense plasmas and highly complex crystalline phases predicted at high pressures and temperatures. Moreover, the powerful technique of X-ray Raman spectroscopy can be extended to heavier elements such as iron, while allowing simultaneous precision X-ray diffraction measure-ments. Furthermore, beyond 25 keV, X-ray absorption of light elements is no longer dominated by the photo effect but by Compton scattering. This may allow the implementation of Compton radiography experiments for dense plasmas providing valuable information on density while enabling complementary scattering diagnostics on the same experiment. In addition, higher energy X-rays will be able to penetrate thick sample sandwiches as required from some shock experiments or material damage studies in bulk samples made of heavy elements. Finally, the use of high-energy X-rays will allow to shield diagnostics more efficiently from parasitic radiation including ultra-intense drive laser system in the regime of relativistic laser-matter interaction. However, most effectively using these techniques will require some development for dedicated diagnostics (e.g.,efficient high-energy X-ray spectrometers) and driver systems (e.g., kJ laser shock driver with decent repetition rate). I will discuss the scientific opportunities of increased XFEL photon energies for HED sciences in light of associated technical challenges.

Speaker: Dominik Kraus

56 Study of heavy elements collisional-radiative behavior using hard XFEL radiation

Heavy elements (Z > 40) are of major importance for many fields of physics related to High-Energy Density Physics. For example, we commonly find them in all inertial confinement fusion related studies, in which the X-rays they generate are used to heat and compress DT capsules. On a broader scope, they are also extensively used are back lighters and tracers in many types of laser-matter interaction studies.

However, due to their very high K-edge thresholds (and also L-edge for very heavy elements as Au), making a detailed study of the hard X-ray emission and the plasma kinetics from these atoms is a very difficult challenge. Collisional-radiative description for such atoms is extremely hard to measure / verify due to the very complex emission of these elements at standard laser generated plasma temperatures (~1-5 keV).
Using a hard XFEL radiation, though, studying the very complex collisional-radiative behavior of heavy elements can be make much easier through the resonant photo-pumping phenomenon. Tuned at very specific frequencies the XFEL can drive photo-excitation of electrons inside the plasma. The result of this excitation is a strong reemission around the pumping frequency. This shows a snapshot of the plasma charge state and excited state populations when the XFEL hits the plasma. Thus, this technique allows to isolate specific parts of the plasma emission depending on the delay between a laser pump and the XFEL (which behaves here as a pump and a probe at the same time).

In this talk, we discuss this technique, its application, and why hard XFELs are the best tools for such studies that can strongly help to stress collisional-radiative, line shape and opacity theoretical models for heavy elements.

Speaker: Florian Condamine (ELI Beamlines)

10:15 Break

57 Hard XFEL radiation for Warm Dense Matter, High Energy Density Studies

Optical lasers are incredible tools able to deliver a lot of energy on a small volume, easily achieving the Warm Dense Matter and more in general High Energy Density regimes.
The use of this hot plasma to compress matter has been proved fundamental to reach conditions not only relevant to basic physics but also for material science, geophysics, astrophysics as well as inertial confinement fusion.

Probing such states is difficult for several reasons: small confinement times due to unstable hydrodynamical conditions and highly compressed matter. That’s why X-FELs are unique machines that can probe solids on small timescales are able to provide important data to constrain theories and simulations.

In this talk I will review possible WDM/HEDP experiments using optical lasers coupled to X-rays above 40keV

Diffraction:
Very important for liquid melting of silicates and other materials relevant to geophysics because it allows to get data over a larger k and thus better resolve the pair distribution function.

Radiography:
Having stronger x-ray would allow to increase the size of probed targets, giving micron scale resolution to study hydrodynamic instabilities, fragmentation and void creation. Coupling this with external magnetic field will help understanding its interaction of shocked material (change in propagation, conductivity etc.) that will be beneficial both for laboratory astrophysics and ICF.

Speaker: Tommaso Vinci (Ecole Polytechnique, LULI)

58 Strong-field physics prospects at 50 keV at European XFEL

Speaker: Dr Uwe Hernandez Acosta (HZDR)

59 Panel discussion and conclusions

60 Poster session awards and closing words

61 Lunch break in the DESY canteen