10th MT ARD ST3 Meeting 2022 in Berlin

7 Sept 2022, 08:30 → 9 Sept 2022, 15:00 Europe/Berlin

Hörsaal 14.51-3147 (Helmholtz-Zentrum Berlin (HZB))

Holger Schlarb (DESY), Erik Bruendermann (KIT), Thorsten Kamps (Helmholtz-Zentrum Berlin / Humboldt-Universität Berlin), Pavel Evtushenko (HZDR / ELBE), Peter Forck (GSI)

The 2022 edition of the MT-ARD-ST3 meeting was held in-person. Two workshops on "Machine Learning" and "MicroTCA for LLRF systems" preceded the meeting.

The 2023 edition will be held in Dresden hosted by HZDR.
See here: https://indico.desy.de/e/2023-st3

The Helmholtz Initiative for Accelerator Research & Development (ARD) was established to strengthen development in accelerator physics and technology and to ensure international competitiveness. In this framework, accelerator scientists push the limits of today’s technology in a research network of six Helmholtz centers (Deutsches Elektronen-Synchrotron (DESY) in Hamburg and Zeuthen, Forschungszentrum Jülich (FZJ), Helmholtz Zentrum for Heavy Ion Research (GSI) in Darmstadt, Helmholtz Zentrum Berlin for Materials and Energy (HZB), Helmholtz Zentrum Dresden-Rossendorf (HZDR), and Karlsruhe Institute for Technology (KIT)), two Helmholtz institutes, eleven universities, two Max-Planck institutes, and the Max-Born institute.

The scope of MT ARD ST3 is “Advanced beam controls, beam diagnostics and beam dynamics” in POF IV. The tenth ARD topical workshop for ST3 will be organized by HZB in Berlin. The workshop is typically held on 3 consecutive days.

This workshop aims to bring scientists from universities and Helmholtz centers together. It shall also serve to further strengthen collaborative projects at and between the different accelerator facilities. The workshop shall also serve to educate young researchers and students participating in projects and experiments within ARD ST3.

Speakers of ST3: Holger Schlarb, DESY; Erik Bründermann, KIT.
Center Contacts of ST3: Thorsten Kamps, HZB; Pavel Evtushenko, HZDR; Peter Forck, GSI.
HZB organizing committee: Thorsten Kamps, HZB; Paul Goslawski, HZB

Corona_measures_ST3_Annual_Meeting_2022.pdf

Map_Karte_HZB_IfP_SBahn.pdf

MT_ARD_ST3_2022_group_photo.jpg

Wednesday, 7 September

08:30 → 12:00 WS "Machine Learning"

Conveners: Andrea Santamaria Garcia (KIT), Pierre Schnizer (HZB)

09:00 → 12:00 WS "MicroTCA for LLRF systems"

Conveners: Julien Branlard (MSK (Strahlkontrollen)), Pablo Echevarria (Helmholtz-Zentrum Berlin)

12:00 → 13:00 Registration (light lunch provided)

Registration for the workshop.
A light lunch will be provided for the participants

13:00 → 14:20 Session 1: Facility Status Talks

Conveners: Peter Forck (GSI), Thorsten Kamps (Helmholtz-Zentrum Berlin / Humboldt-Universität Berlin)

13:00 Welcome to HZB

Speaker: Andreas Jankowiak (HZB)

13:15 HZB facility talk

Speaker: Markus Ries (Helmholtz-Zentrum Berlin)

20220907_ARDST3_HZBfacility_final.pdf

20220907_ARDST3_HZBfacility_final.pptx

13:40 DESY facility talk

Speaker: Holger Schlarb (MSK (Strahlkontrollen))

ARD-ST3-DESY-Acc_20220907_final_wo_backup.pdf

14:05 PITZ facility talk

In this talk, we will report the activities at the Photo Injector Test
facility at DESY in Zeuthen (PITZ), focusing on the conditioning of the
new generation RF gun - Gun5.1, the first results of the THz SASE FEL
lasing and the planned electron FLASH radiotherapy experiments. The
current status of photocathode laser shaping, green cathode studies and
beam dynamics studies will also be discussed.

Speaker: Xiangkun LI (DESY Zeuthen)

PITZ_overview_XKL.pdf

14:20 → 14:35 Short break

14:35 → 15:45 Session 1: Facility Status Talks

Convener: Thorsten Kamps (Helmholtz-Zentrum Berlin / Humboldt-Universität Berlin)

14:35 HZDR facility talk

Speaker: Pavel Evtushenko (HZDR / ELBE)

2022 ARD-ST3-HZDR P.Evtushenko Rev.1.pptx

15:00 KIT facility talk

This contribution reports the status of the KIT facilities and presents highlights of the KIT accelerator research in context of ARD-ST3. Our activities based on the two electron accelerators in operation, the Karlsruhe Research Accelerator (KARA) and the Ferninfrarot- Linac Und Test-Experiment (FLUTE), comprise developments of ultra-fast beam diagnostics and beam dynamics studies with corrugated structures or in new operation modes, but also include the utilisation of machine learning concepts and energy related research with regard to efficiency and grid stability. Within the cSTART project, KIT is realising a new compact storage ring for accelerator R&D both in-house and within national or even international cooperations.

Speaker: Bastian Haerer (Karlsruhe Institute of Technology (KIT))

2022-09-07_MT-ARD-ST3_Facility_Report_KIT.pdf

15:25 GSI facility talk

GSI is hosting a very flexible heavy ion accelerator facility. During the beam time in 2022 protons, uranium and many other ions were accelerated. The related challenges for the LINAC and synchrotron operation are reported. Beam cooling and deceleration are further topics at the GSI storage rings to provide user with ion in extreme conditions. Examples for those beam generations will be discussed.

Speaker: Peter Forck (GSI)

GSI facility Forck 20220907.pdf

GSI facility Forck 20220907.pptx

15:45 → 16:10 Coffee break

16:10 → 16:55 Tutorials: Tutorial 1

Convener: Erik Bruendermann (KIT)

16:10 Machine learning application examples at BESSY

Speaker: Gregor Hartmann (HZB)

MT-ST3-ARD_GregorHartmann_pdf.pdf

Thursday, 8 September

09:00 → 10:20 Session 2: Beam Diagnostics: Talks

Convener: Pavel Evtushenko (HZDR / ELBE)

09:00 Demonstration of nA current resolution of the Cyogenic Current Comparator

The Cryogenic Current Comparator (CCC) at the heavy-ion storage ring CRYRING@ESR at GSI provides a calibrated non-destructive measurement of beam current with a resolution of 10 nA or better. With traditional diagnostics in storage rings or transfer lines a non-interceptive absolute intensity measurement of weak ion beams (< 1 µA) is already challenging for bunched beams and virtually impossible for coasting beams. Therefore, at these currents the CCC is the only diagnostics instrumentation that gives reliable values for the beam intensity independently of the measured ion species and without the need for tedious calibration procedures. Herein, after a brief review of the diagnostic setup, an overview of the operation of the CCC with different stored ion beams at CRYRING is presented. The current reading of the CCC is compared to the intensity signal of various standard instrumentations including a Parametric Current Transformer (PCT), an Ionization Profile Monitor (IPM) and the Beam Position Monitors (BPMs). It was shown that the CCC is a reliable instrument to monitor changes of the beam current in the range of nA.

Speaker: Lorenzo Crescimbeni (Friederich schiller universität jena)

2022_St3_berlin_LC_presentation_CCC.pdf

09:20 Distributed Acoustic Sensing for monitoring seismic and acoustic pertubation on accelerators

The WAVE initiative investigates and designs a seismic and geo-acoustic measurement network in and around and around the Science City Hamburg Bahrenfeld. WAVE is a unique and innovative infrastructure for geophysics, physics and especially for large-scale research facilities.
A key element of WAVE is the widespread use of modern seismic sensors, in particular distributed acoustic sensing (DAS). This technology uses fiber optic cables as sensitive seismic sensors. It enables ground motion data to be recorded at an unprecedented spatial density over long distances.
I am going to present some first data taken around the DESY campus and especially in the XFEL accelerator tunnel to discuss applications for improving beam stability in accelerators.

Speaker: Markus Hoffmann (MSK (Strahlkontrollen))

2022-09-08-ARD-ST3-hoffmann-WAVE.pdf

tunneldurchsage1.mp3

09:40 Ultra-fast line-camera KALYPSO for electron beam diagnostics

Synchrotron light sources operate with bunch repetition rates in the MHz regime. The longitudinal and transverse beam dynamics of these electron bunches can be investigated and characterized by experiments employing linear array detectors. To improve the performance of modern beam diagnostics and overcome the limitations of commercially available detectors, we have developed KALYPSO, a detector system operating with an unprecedented frame rate of up to 12 MHz. To facilitate the integration in different experiments, a modular architecture has been utilized. Different semiconductor micro-strip sensors, based on Si, TI-LGAD, InGaAs, PbS, and PbSe with the quantum efficiency optimized at different photon energies, can be connected to the custom designed low noise front-end ASIC operating at megaframerates. The front-end electronics is integrated within a heterogeneous DAQ consisting of FPGAs and GPUs, which allows the implementation of real-time data processing. In this contribution, the performance results and the ongoing technical developments will be presented.

Speaker: Meghana Mahaveer Patil (KIT)

03_MML_ARD_ST3_2022_upload.pdf

10:00 Implementation and first test results of the STRIDENAS beam profile monitor

Electron bunches with charges in the order of 10 fC can be produced at the ARES linac and are used for experiments with medical applications or studies of novel acceleration techniques. To characterize such bunches, sufficient sensitivity of the diagnostics devices is required. The STRIDENAS beam profile monitor is designed to measure such sub-10 fC charge beams. The device is based on silicon strip sensors from the ATLAS inner tracker upgrade, which feature a pitch of 75 micrometers. A detector prototype has been built and installed in a dedicated experimental chamber at ARES. First beam profile measurements have been performed. In this talk, the detector setup and first measurement results are presented.

Speaker: Sonja Meike Jaster-Merz (MPY1 (MPY Fachgruppe 1))

STRIDENAS_detector_ST3_workshop_Jaster-Merz.pptx

10:20 → 10:53 Session 2: Beam Diagnostics: Speed Talks

Convener: Peter Forck (GSI)

10:20 4D tomography measurements and 5D simulations at ARES

The ARES linear accelerator at DESY aims to deliver stable and well-characterized electron bunches with durations down to the sub-fs level. Such bunches are well suited to study the injection into novel high-gradient acceleration structures or to test diagnostics devices. For such applications, it is advantageous to have full and detailed knowledge of the beam properties. Tomographic methods have proven to be a key tool for beam phase space reconstructions. Based on these techniques, a novel beam diagnostics method is being developed. It combines a quadrupole-based transverse phase-space tomography with the variable streaking direction of a PolariX TDS. This method resolves the full 5-dimensional phase space (x, x', y, y', t) of the bunches including their transverse and longitudinal distributions and correlations. In simulation studies, this method shows excellent agreement between the reconstructed and the original distribution for all five planes. Here, the method and its working principle as well as preparatory steps towards a first experimental measurement at ARES are presented.

Speaker: Sonja Meike Jaster-Merz (MPY1 (MPY Fachgruppe 1))

5D_tomography_ST3_workshop_Jaster-Merz.pdf

10:23 Electro-Optical Diagnostics at KARA

Electro-optical (EO) methods are well-proven diagnostic tools, which are utilized to detect THz fields in countless experiments. The world’s first near-field EO sampling monitor at an electron storage ring was developed and installed at the KIT storage ring KARA (Karlsruhe Research Accelerator) and optimized to detect longitudinal bunch profiles. This experiment with other diagnostic techniques builds a distributed, synchronized sensor network to gain comprehensive data about the phase-space of electron bunches as well as the produced coherent synchrotron radiation (CSR). Furthermore, a far-field EO setup to measure the THz spectrum of the CSR in single-shot is currently implemented. In this contribution, we will give an overview of current EO activities at KARA.

Speaker: Gudrun Niehues (KIT)

Niehues-2022-ST3-Berlin.pdf

10:26 Development of an electro-optical longitudinal bunch profile monitor at KARA towards a beam diagnostics tool for FCC-ee

The Karlsruhe Research Accelerator (KARA) at KIT features an electro-optical (EO) near-field diagnostics setup to conduct turn-by-turn longitudinal bunch profile measurements in the storage ring using electro-optical spectral decoding (EOSD). Within the Future Circular Collider Innovation Study (FCCIS) an EO monitor using the same technique is being conceived to measure the longitudinal profile and center-of-charge of the bunches in the future electron-positron collider FCC-ee. This contribution provides an overview of the EO near-field diagnostics at KARA and discusses the development and its challenges towards an effective beam diagnostics concept for the FCC-ee.

Speaker: Micha Reißig (Karlsruher Institut für Technologie (KIT))

2022-09-07_MT-ARD-ST3_EONF-Concept_Reissig.pdf

10:29 THz spectrometer using diffraction radation for parasitic current profile measurements at European XFEL

The broadband and single-shot spectrometer CRISP detects coherent diffraction radiation at European XFEL in the infrared and THz regime for current profile measurements. The noninvasive radiation source and the MHz capability of spectrometer allows an individual characterization of all bunches of the European XFEL bunch train. This poster presents the working principle of the spectrometer, the current profile reconstructions and comparative measurements with other diagnostics.

Speaker: Nils Maris Lockmann (MSK (Strahlkontrollen))

speedtalk_lockmann_hzb22.pdf

10:32 Towards direct detection of the shape of CSR pulses with fast THz detectors

Coherent synchrotron radiation (CSR) is emitted when the emitting structure is equal to or smaller than the observed wavelength. Consequently, these pulses are very short and most detectors respond with their impulse response, regardless of the pulse length and shape. Here we present single-shot measurements performed at the Karlsruhe Research Accelerator (KARA) using a fast real-time oscilloscope and Schottky barrier detectors sensitive in the sub-THz range. The time response of this setup to CSR pulses emitted by electron bunches during the microbunching instability is shown to be sensitive to the shape of the electron bunch. Our results show how, in the future, the shape of electron bunches can be directly measured using a straightforward setup.

Speaker: Johannes Steinmann (Karlsruhe Institute of Technology (KIT), IBPT)

2022-09-07 MT-ARD-ST3_SpeedTalk.pdf

10:35 Towards the Detection and Monitoring of Ageing Precursors on the XFEL Machine Beam Control Hardware

The hardware deployed by the Machine Beam Control group (MSK) at the European XFEL is used in critical operation systems. This includes low-level RF control, special diagnostics and time synchronization, making the devices highly dependable. At the same time, this hardware operates under harsh environmental conditions, potentially causing degradation and failures of the board components in the long term. In this poster we survey different ageing mechanisms that affect the hardware under study, together with literature describing their measurable effects. Furthermore, we discuss approaches that can yield an overall status of the hardware ageing, which we will evaluate, combine, and leverage in future work for predictive maintenance.

Speaker: Leandro Lanzieri (DESY)

mt_ard_st3_presentation_lanzieri.pdf

10:38 KINGFISHER: A Framework for Fast Machine Learning Inference for Autonomous Accelerator Systems

Modern particle accelerator facilities allow new and exciting beam properties and operation modes. Traditional real-time control systems, albeit powerful, have bandwidth and latency constraints that limit the range of operating conditions currently made available to users. The capability of Reinforcement Learning to realize self-learning control policies by interacting with the accelerator is intriguing. The extreme dynamic conditions require fast real-time components throughout the whole control loop from the diagnostic, with novel and intelligent detector systems, all the way to the interaction with the machine. In this talk, the novel KINGFISHER framework based on the modern Xilinx Versal devices will be presented. Versal combines several computational engines, specifically combining powerful FPGA logic with programmable AI Engines in a single device. Another key characteristic of this system is the native integration with the fastest beam diagnostic tools already available, i.e. KAPTURE and KALYPSO. In this contribution, the recent beam test and preliminary results aiming to control the microbunching instability by applying modulations using the Low Level RF and Bunch By Bunch systems at KARA at KIT will be presented.

Speaker: Luca Scomparin (KIT IPE)

[20220908]_KINGFISHER_ARD_ST3_speedposter.pdf

10:41 Ultra-fast Longitudinal Bunch Diagnostic at the KARA Booster Synchrotron

At the KARA accelerator, after the electron bunches are per-accelerated by a 3 GHz microtron, a booster synchrotron operating at 500 MHz is used to increase the energy of the electrons from 50 MeV to 500 MeV, before they are injected into the storage ring. Due to various effects, the injection efficiency from to the ring is rather low. To investigate these inefficiencies and remedy them, fast beam diagnostics are needed.
Currently the sum signal from a beam position monitor and an oscilloscope are used to measure an average longitudinal beam profile over many turns, which is insufficient to observe e.g. the injection period.
Therefore, we propose to replace the oscilloscope with a high-speed digitizer with the appropriate trigger capabilities and to deploy a photodiode at the synchrotron light port of the booster synchrotron.
Doing so enables turn-by-turn and bunch-by-bunch diagnostic needed to investigate events that differ over a few turns, as well as instabilities in-between the electron bunches.

Speaker: Marvin Noll (KIT)

mt_ard_st3_22-talk.pdf

10:44 FLASHlab@PITZ: Preparations for First Beam Experiments on FLASH Radiation Therapy at PITZ

FLASHlab@PITZ is an R&D platform for electron FLASH and very high energy electron radiation therapy and radiation biology, under preparation at the Photo Injector Test facility at DESY in Zeuthen (PITZ).
The available beam parameters are unique: ps scale electron bunches with up to 5 nC bunch charge at MHz repetition rate in bunch trains of up to 1 ms in length, currently 22 MeV (upgrade to 250 MeV planned). Individual bunches can provide peak dose rates up to 10^14 Gy/s and 10 Gy can be delivered in ps. On request, each bunch of the bunch train can be guided to a different transverse location, so that either a "painting" with micro beams or a cumulative increase of absorbed dose using a wider beam distribution can be realized at the tumor. Full tumor treatment can be completed within 1 ms, mitigating organ movement issues.
With extremely flexible beam manipulation capabilities, FLASHlab@PITZ will be able to cover the current parameter range of successfully demonstrated FLASH effects and extend the parameter range towards yet unexploited short treatment times and high dose rates.
A summary of the plans for FLASHlab@PITZ and the status of its realization will be presented.

Speaker: Frank Stephan (DESY)

FLASHlab@PITZ_speedposter@HZB.pdf

10:47 Experimental Slice Emittance Reduction at PITZ using Laser Pulse Shaping

The Photo Injector Test Facility at DESY in Zeuthen (PITZ) optimises electron sources for their use at the free-electron lasers FLASH and European XFEL in Hamburg. Non-linear space charge forces after emission lead to an increase of the transverse (slice) emittance. Photocathode laser pulse shaping allows to alter the space charge forces. This contribution shows a method to measure the slice emittance using a single-slit scan and a transversely deflecting structure, as well as measured slice emittance of three beams, emitted using laser pulses with different shapes.

Speaker: Raffael Niemczyk (Z_PITZ (Betrieb und Forschung))

2022-09-08_ARD_ST3_Annual_Meeting_speedposter_slides_slice_emittance_Niemczyk.pdf

2022-09-08_ARD_ST3_Annual_Meeting_speedposter_slides_slice_emittance_Niemczyk.pptx

10:50 Laser arrival time monitor for FELs

The time arrival stability of the electrons is as good as 5-10 fs rms, but the arrival time of the optical lasers is on the order of 10 fs rms after correction. Here will be presented a laser arrival time monitor: the arrival time of the optical pulses will be measured against a reference from a length-stabilized fiber. With a measurement as close as possible to the interaction point, instabilities due to transport can be evaluated and if possible corrected.

Speaker: Anne-Laure Calendron (MSK (Strahlkontrollen))

220908_ARD-ST3_Poster_SpeedTalk_ALC.pdf

220908_ARD-ST3_Poster_SpeedTalk_ALC.pptx

10:53 → 11:03 Coffee Break

11:03 → 12:33 Session 2: Beam Diagnostics: Posters

Convener: Peter Forck (GSI)

12:33 → 14:00 Lunch (on your own)

Participants are free to lunch on their own on Adlershof campus.

14:00 → 15:20 Session 3: Controls/Seeding/DAQ: Talks

Convener: Holger Schlarb (MSK (Strahlkontrollen))

14:00 Machine learning to predict and control beam properties

Speaker: Andrea Santamaria Garcia (KIT)

2022-09-08_ST3_SANTAMARIAGARCIA.pptx

14:20 Beam size prediction at Bessy II with ML/AI

Light sources are used by many users at the same time. Each user is able to adjust different settings, e.g. insertion device parameters. Light source operation tries to minimize their crosstalk, i.e. settings of one user should not change the beam of a different user. The vertical beam size is a parameter that should be tightly controlled.

Data reveals that the vertical beam size takes a long time for settling, after settings were changed. Thus, to model the parameter, it needs to be treated as a time-dependent problem.

In this talk, I describe the challenge to model the vertical beam size using machine learning methods, especially why LSTM cells should be used. I present which predictions have been reached reliably and what remains to be dealt with to provide it in user operation.

Speaker: Alexander Schuett (Helmholtz-Zentrum Berlin)

schuett_vertical_beam_pred.pdf

14:40 Towards femtosecond-scale electron bunches with high stability for accelerator R&D on the ARES linac at DESY

The ARES linac at DESY aims at producing and characterizing ultrashort (fs to sub-fs) electron bunches with high stability for cutting-edge applications related to accelerator R&D (e.g. Advanced and compact longitudinal diagnostics development, medical applications i.a. in collaboration with UKE, external injection into advanced accelerating structures, etc.). The current status and perspectives of the ARES linac in terms of beam properties and beamline completion will be presented. A special focus will be put on the bunch duration and stability measurements, which are the core goals of ARES. An overview on the already performed, ongoing and future experiments at ARES will also be given.

Speaker: Thomas Vinatier (MPY1 (MPY Fachgruppe 1))

Vinatier_Talk_ARDST3-workshop_08092022.pdf

Vinatier_Talk_ARDST3-workshop_08092022.pptx

15:00 Making controls groups’ systems more accessible to scientist with simple Python interfaces and cleaner code

This talk names the different computer and data systems that are needed for efficiently working with accelerators for the example of KIT's IBPT's accelerators. It shows why and how to make them accessible to accelerator physicist of various kind via cleanly coded Python wrappers and how to keep them maintainable.

Speaker: Gethmann Julian (KIT)

2022-09-08_MT_ARD_ST3_Gethmann_ControlSystem.pdf

2022-09-08_MT_ARD_ST3_Gethmann_ControlSystem.pptx

15:20 → 15:56 Session 3: Controls/Seeding/DAQ: Speed Talks

Convener: Julian Gethmann (KIT)

15:20 Development of a multi-axis Motion Controller in MicroTCA.4

DESY is developing a MicroTCA.4-based multi-axis motion controller: DAMC-MOTCTRL. This board is a contribution to the ecosystem, since it enables controlling motion in big experiments from within the MicroTCA crate. It is designed to move up to 48 stepper motors per card in parallel - which means each card replaces up to 6 VME cards. One major benefit is the possibility to aggregate multiple cards inside crate and across DESY campus. This allows to perform position-synchronous data acquisition. Using the MicroTCA features, this device can interact with virtually any other MicroTCA card and trigger user-programmable actions.

In this talk, the the design, it's current state and the latest developments will be presented.

Speaker: Michael Fenner (MSK (Strahlkontrollen))

mtca4-multi-axis-motion-controler-ard-st3-2022-web.pdf

15:23 Integration of Yocto and Jupyter Lab into the MSK Firmwarework for MPSoCs

With the advent of modern systems on chips (SoCs) and multiprocessor systems on chips (MPSoCs), there are clear advantages to using embedded Linux as an operating system. It is an open-source operating system that supports multiprocessing, and there are a variety of open-source hardware drivers and application software. The most important advantage, however, is that chip vendors provide extensive libraries and high-level APIs for Linux to take advantage of features such as hardware acceleration and heterogeneous processing.

DESY MSK has chosen the Yocto Project framework to create custom embedded Linux images for the SoC/MPSoC-based Advanced Mezzanine Cards within the MicroTCA systems. We will present our approach to integrating the Yocto build process into the existing framework of MSK for building FPGA artifacts. We will show how we plan to add, update, and maintain software components and the status of this work.

Speakers: Michael Randall (MSK (Strahlkontrollen)), Seyed Nima Omidsajedi (MSK (Strahlkontrollen))

Integration of Yocto and Jupyter Lab into the MSK Firmware Framework for MPSoCs_Omidsajedi.pdf

15:26 Attosecond RF Receivers Based on Carrier Suppression: Status update

On this poster, we will present a status update on the carrier suppression interferometer based RF recevier with the last measurement restults and future plans for tests at CMTB/DESY.

Speaker: Matthias Hoffmann (MSK (Strahlkontrollen))

MT-Speedtalk-ARD-ST3-CSI_Hoffmann.pdf

15:29 Comparison of the Spectro-Temporal Properties of Echo-Enabled and High-Gain Harmonic Generation Free-Electron Laser Pulses

The external seeding scheme Echo-Enabled Harmonic Generation (EEHG) utilizes two modulators and two chicanes to manipulate the longitudinal phase space of an electron beam to achieve bunching at higher harmonics of the seed laser wavelength. High-Gain Harmonic Generation (HGHG) makes use of a single modulator-chicane setup, but is limited to lower harmonics due to more stringent requirements on the energy modulation and a consequently larger induced beam energy spread. In both seeding techniques, different combinations of energy modulation and longitudinal dispersion can result in the same amount of bunching at a certain harmonic. A comparison of EEHG and HGHG at the 15th harmonic is presented under particular consideration of the impact of the energy modulation amplitudes on the bunching properties and the spectro-temporal characteristics of the free-electron laser (FEL) radiation. The corresponding numerical modelling and simulations are performed within the parameter range of the future upgrade of the FEL user facility FLASH at DESY.

Speaker: Fabian Pannek (UNI/EXP (Uni Hamburg, Institut fur Experimentalphysik))

15:32 Transverse and Longitudinal Modulation of Photoinjection Pulses at FLUTE

To generate the electrons to be accelerated, a photoin-jection laser is used at the linac-based test facility FLUTE (Ferninfrarot Linac-Und Test Experiment) at the Karlsruhe Institute of Technology (KIT). The properties of the laser pulse, such as intensity, laser spot size or temporal profile, are the first parameters to influence the characteristics of the electron bunches. In order to control the initial parameters of the electrons in the most flexible way possible, the laser optics at FLUTE are therefore supplemented by additional setups that allow transverse and longitudinal laser pulse shaping by using spatial light modulators (SLMs). In the future, the control of the SLMs will be integrated into a machine learning (ML) supported feedback system for the optimization of the electron bunch properties. In this contribution , the first test experiments and results on laser pulse shaping at FLUTE on the way to this project are presented.

Speaker: Matthias Nabinger (KIT)

2022-09-07_09_MT-ARD-ST3_Nabinger_Speedtalk.pdf

15:35 Bayesian Optimization for the Control Parameters of the Optical Synchronization System at European XFEL

Linear particle accelerators require outstanding synchronization of the subsystems to provide high quality results for temporally resolved experiments. Considering the laser-based synchronization system at the European X-Ray Free-Electron Laser, the optimization process involves searching for the global optimum in a high-dimensional parameter space whereby safety constraints are fulfilled. For this purpose, Bayesian optimization is iteratively applied on subspaces of the high-dimensional optimization problem to maintain numerical tractability. Furthermore, modifications to an existing safety mechanism are developed which show significantly improved convergence rates. This opens the applicability to even higher-dimensional problems with high iteration cost.
The developed algorithm was applied on the main branch of the optical synchronization system.

Speaker: Jannis Luebsen (MSK (Strahlkontrollen))

Bayesian_Optimization_for_the_Control_Parameters_EuXFEL.pdf

15:38 Status of Beam-Based Feedback Research and Development for CW Linac ELBE

The CW operation mode of the superconducting linear accelerator ELBE allows
reinterpreting a beam-based feedback control problem as a regulation goal.
By moving the focus of attention to low-frequency RF noise, i.e. the disturbance
that makes a significant contribution to electron beam fluctuations, the necessity
to pursue a bandwidth-demanding bunch-by-bunch control can be avoided.
Simultaneously, the fundamental bandwidth limitation of a superconducting RF
cavity, i.e. the usual actuator in such control schemes, no longer poses a problem.

Furthermore, the benefit of implementing the resulting beam-based feedback regulator
using an FPGA is twofold. Firstly, the low-latency nature of FPGAs allows dealing with
fast processes, such as the regulation of an electron bunch arrival time. Secondly,
the high configurability of FPGAs enables the implementation of sophisticated regulation
algorithms, e.g. an optimal H2 regulator in its state-space representation.

Accordingly, in this report we provide the details of the work that has been done
so far, both in control engineering and digital logic domains. We support our
work by demonstrating the results of the latest machine studies at ELBE.
These results show not only a reduction in the bunch arrival time jitter,
but also a correspondence between a model and a measured data.

Speaker: Andrei Maalberg (Helmholtz-Zentrum Dresden-Rossendorf)

20220905_1_maalberg_slides.pdf

15:41 Learning-based Optimisation of Particle Accelerators Under Partial Observability Without Real-World Training

Reinforcement learning (RL) has enabled the development of intelligent controllers for complex tasks that previously required human intuition to solve. In the context of particle accelerators, there exist many such tasks and solving them with conventional methods takes away from scarce experiment time and limits the operability of accelerators. We demonstrate how to successfully apply RL to the optimisation of part of a linear particle accelerator under highly limited partial observability and without requiring expensive beam time for training on the real machine. Our method outperforms conventional optimisation algorithms in both the achieved result and time taken, and achieves close to human-level performance. In the future, RL-based controllers like ours will enable more challenging beam configurations and significantly reduce the time required to attain them, thereby increasing both quality and quantity of experimental output of accelerator facilities and consequently enable scientific advances in the research fields served by these machines.

Speaker: Jan Kaiser (DESY)

Slides - Learning-based optimisation of particle accelerators.pdf

15:44 The feedback LMS resonance control for the SRF cavities in CW/LP

Future development in the LLRF system is needed to suppress the microphonics disturbances to drive SRF cavities in the EUXFEL within CW/LP field stability.
The current CW LLRF system implements a narrowband Least Mean Square (LMS) Active Noise Controller (ANC) to compensate for sinusoidal microphonics disturbances.
The major limitation of using narrowband LMS ANC is that it can reject only sinusoidal disturbances.So, if the noise source frequency changes over time, the narrowband ANC cannot track and cancel the disturbance.
Therefore wideband LMS ANC can be considered for compensating for the disturbances over a broad range of frequencies. Compared to the feedforward LMS ANC, the feedback LMS ANCs can correct the disturbances regardless of whether they originate outside or inside the controlled system. Hence the feedback LMS ANC can improve the resonance control of a high Ql cavity system.
This poster discusses the proposed Feedback LMS ANC algorithm implementation in FPGA with offline verification results. The implemented design is compact and pipelined, CPU accessible, operates at 100 MHz, and can implement a filter with an order of up to 1000.

Speaker: Shweta Prasad

Presentation_HZB (1).pdf

15:47 Adaptive Computing Accelerator Platform (ACAP) first experience and Vitis Tool chain

Developers have proposed various hardware accelerators to improve the CNN inference performance on embedded platforms. Recently, Xilinx announced its first 7-nm FPGA accelerator, the Versal ACAP, delivering a high-performance, heterogeneous computing platform adaptable to the application requirements. However, as early studies were concerned with the most common deep learning architectures for CNN, the implementation and analysis of the Versal ACAP performance with customized CNN architectures are yet to be explored.
In this study, we implement one of the CNN architectures considered at the European XFEL and compare its performance to a state-of-the-art GPU and other FPGA generation. In addition, this study evaluates the validity of using the quantization methods for critical regression applications. It presents a complete analysis of the results built upon the device time traces, providing recommendations for configuring the runtime parameters.
The experimental results confirm a superior performance of the Versal ACAP in terms of latency and throughput.

Speaker: Gianluca Martino (MSK (Strahlkontrollen))

20220908_ml_accelerators.pdf

20220908_ml_accelerators.pptx

15:50 Generic FPGA Firmware Framework

In the beam controls group in DESY, the FPGA firmware is developed with the use of a custom framework, called FWK. This framework has been developed in order to provide FPGA firmware for European XFEL for LLRF, special diagnostic and synchronization systems.
In the past two years FWK went a number of changes which allowed to make it open source. The main goal of the changes is to provide a universal framework that could significantly facilitate cooperation in the development of FPGA firmware.
The current state of the firmware framework and its idea and usage will be presented.

Speaker: Lukasz Butkowski (DESY)

ard-st3-2022_lukasz_butkowski.pdf

ard-st3-2022_lukasz_butkowski-poster.pdf

15:53 Precision RF Cable shield measurement tech.transfer to industry

We present in cooperation with the industry a precision rf cable shield measurement setup to be able to measure the transfer impedance and the screening attenuation. We discuss the proper selection of rf-cables, quality control issues during the production and usage and how to avoid (semi) faulty transitions.

Speaker: Frank Ludwig (DESY)

ARDST3_2022_09_06_FL_Speedtalk_Poster.pptx

15:56 → 16:06 Gruppenphoto

16:06 → 16:16 Coffee Break

16:16 → 17:36 Session 3: Controls/Seeding/DAQ: Posters

Convener: Julian Gethmann (KIT)

18:00 → 21:00 Dinner BBQ

The BBQ will happen in front of the SEALAB/bERLinPro hall. BBQ will be setup from 18:00. We will serve food from 18:30 to 20:00. The BBQ ends at 21:00. This is an outside event. In case of bad weather we will move into the SEALAB/bERLinPro hall.

Friday, 9 September

09:00 → 10:20 Session 4: Beam Dynamics: Talks

Convener: Erik Bruendermann (KIT)

09:00 Ultra-short pulses and low jitter for time-resolved experiments at the SRF photoinjector of SEALAB

In the last years, the visualization of structural dynamics, which take place on time scales as short as few femtoseconds has been complemented by pump-probe techniques that employ relativistic electrons as probes, e.g. ultrafast electron diffraction (UED). These applications demand not only extreme beam quality in 6‑D phase space such as few nanometer transverse emittances and femtosecond bunch lengths, but also equivalent beam stability. Although these utmost requirements have been demonstrated by a compact setup with a high‑gradient electron gun with state‑of‑the‑art laser technologies, this approach is fundamentally restricted by its nature for compressing the electron bunches in a short distance by a ballistic bunching method while also suppressing the time-of-flight jitter of the electrons. Here, we propose a new methodology that pushes the limit of timing jitter and bunch compression simultaneously beyond the state‑of‑the‑art by utilizing consecutive RF cavities. This accelerator layout already exists for energy recovery linear accelerator demonstrators such as SEALAB in Helmholtz-Zentrum Berlin. Furthermore, the superconducting nature of the RF cavities in the beam-line is capable of providing MHz repetition rates, which are out of reach for most conventional high‑gradient electron guns. Hence, the proposed accelerator layout offers a new scientific case for similar ERL demonstrators without significant modifications, while providing enhanced signal to noise performance when compared to other purpose-built UED accelerators.

Speaker: Beñat Alberdi Esuain (Helmholtz-Zentrum Berlin)

ST3_talk_final_Benat.pdf

09:20 High-resolution 2D streak camera investigations: Injection dynamics at BESSY II

High-Resolution 2D Streak Camera Investigations:
Injection Dynamics @ BESSY II
The BESSY optical timing beamline with its high resolution 2D streak camera system will be presented. The system can be optimized for high time resolution (< 0.6 ps rms), or single-shot sensitivity (single turn, single bunch), or high spatial resolution (< 0.1 mm rms or even below by combination with interferometry).

The dynamics of either a kicked bunch or an injected bunch are examined using a series of turn-resolved single-shot data. Tunes as well as damping times are extracted for horizontal and also longitudinal motion. Turn-separated 2D images show the evolution of head-tail modes, nonlinearities, and the influence of chromaticity on the time evolution of an injected bunch.

Speaker: Gregor Schiwietz (Helmholtz-Zentrum Berlin (HZB))

Abstract.txt

ARD_ST3-GS_final.pdf

Video1_short2.mp4

Video2_short2.mp4

09:40 Alternating Phase Focusing Beam Dynamics for Drift Tube Linacs

The Helmholtz Lienar Accelerator has reached the next project milestone with the commissioning of the superconducting Advanced Demonstrator cryomodule, comprising four superconducting crossbar H-mode (CH) cavities and superconducting steerer magnets. Parallel to the commissioning of the superconducting main accelerator, the injector linac is revised for integration into the standalone linac tunnel under construction. An Electron Cyclotron Resonance Ion Source (ECRIS) together with an Radio Frequency Quadrupole (RFQ) will supply beam to a normal conducting Interdigital H-mode (IH) pre-accelerator unit, providing for beam energy gain from 300 to 1400 keV/u. The revision of the injector Linac allows to re-design the IH cavity using an Alternating Phase Focusing (APF) beam dynamics scheme in order to yield two quadrupole-lens free cavities and to extend the injector with further beam diagnostics and beam steerers. Thus, the HELIAC-injector layout applying APF for continuous wave heavy ion acceleration is presented.

Speaker: Simon Lauber (HIM Mainz, GSI Darmstadt, JGU Mainz)

MTARDST3_lauber_final.pdf

10:00 Energy compressor for PWA Injector PETRA IV

Speaker: Sergey Antipov (MPY (Beschleunigerphysik))

Antipov_MT_ARD_ST3_Meeting_09.09.2022.pdf

10:20 → 10:50 Session 4: Beam Dynamics: Speed Talks

Convener: Michael Kuntzsch (HZDR)

10:20 THz@PITZ: First Commissioning Results

Research and development of an accelerator-based THz source prototype for pump-probe experiments at the European XFEL are ongoing at the Photo Injector Test Facility at DESY in Zeuthen (PITZ). A proof-of-principle experiment to generate THz SASE FEL radiation using an LCLS-I undulator driven by an electron bunch from the PITZ accelerator has been prepared. After four years of designs and construction, the first commissioning with an electron beam was started in July 2022. This contribution presents and discusses the experience and results of the first commissioning.

Speaker: Prach Boonpornprasert (Z_PITZ (Betrieb und Forschung))

1stTHz@PITZ_ARDST32022_Boonpornprasert.pdf

10:23 Bayesian optimization of simulated THz radiation at FLUTE

The linac-based test facility FLUTE (Ferninfrarot Linac Und Test Experiment) at KIT will be used to study novel accelerator technology and provide intense THz pulses. In this paper, we present start-to-end simulation studies of FLUTE with different bunch charges. We employ a parallel Bayesian optimization algorithm for different bunch charges of FLUTE to find optimized accelerator settings for the generation of intense THz radiation.

Speaker: Chenran Xu (KIT)

2022-MT-ARD-ST3-Xu_speedtalk.pdf

10:26 Predicting the transverse emittance of space charge dominated beams using the phase advance scan technique and a fully connected neural network

The transverse emittance of a charged particle beam is an important figure of merit for many accelerator applications, such as ultra-fast electron diffraction, free electron lasers and the operation of new compact accelerator concepts in general. One of the easiest to implement methods to determine the transverse emittance is the phase advance scan method using a focusing element and a screen. This method has been shown to work well in the thermal regime. In the space charge dominated laminar flow regime, however, the scheme becomes difficult to apply, because of the lack of a closed description of the beam envelope including space charge effects. Furthermore, certain mathematical, as well as beamline design criteria must be met in order to ensure accurate results. In this work we show that it is possible to analyze phase advance scan data using a fully connected neural network (FCNN), even in setups, which do not meet these criteria. In a simulation study, we evaluate the perfomance of the FCNN by comparing it to a traditional fit routine, based on the beam envelope equation. Subsequently, we use a pre-trained FCNN to evaluate measured phase advance scan data, which ultimately yields much better agreement with numerical simulations. To tackle the confirmation bias problem, we employ additional mask-based emittance measurement techniques.

Speaker: Dr Frank Mayet (MPY1 (MPY Fachgruppe 1))

FCNN_Emittance_SpeedTalk_v2.pdf

10:29 Observations of Effects on Beam Dynamics at Negative Momentum Compaction Factors

For the development of future synchrotron light sources new operation modes often have to be considered. One such mode is the operation with a negative momentum compaction factor to provide the possibility of increased dynamic aperture. For successful application in future light sources, the influence of this mode has to be investigated. At the KIT storage ring KARA (Karlsruhe Research Accelerator), operation with negative momentum compaction has been implemented and the dynamics can now be investigated. Using a variety of high-performance beam diagnostics devices it is possible to observe the beam dynamics under negative momentum compaction conditions. This contribution presents different aspects of the results of these investigations in the longitudinal and transversal plane.

Speaker: Patrick Schreiber (KIT)

2022-09-09_MT-ARD-ST3-NegativeAlpha_PSchreiber.pdf

10:32 Simulation of the effect of corrugated structures on the longitudinal beam dynamics at KARA

Two parallel corrugated plates will be installed at the KIT storage ring KARA (KArlsruhe Research Accelerator). This impedance manipulation structure will be used to study and eventually control the beam dynamics and the emitted coherent synchrotron radiation (CSR).
In this contribution, we present the influence of the parameters of the structure on its impedance and the results obtained with the Vlasov-Fokker-Planck solver Inovesa showing the impedance impact of different corrugated structures on the CSR power.
Supported by "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology" (KSETA) and by the DFG project 431704792 in the ANR-DFG collaboration project ULTRASYNC.

Speaker: Mr Sebastian Maier (KIT)

2022-09-07_09_MT_ARD_ST3_Maier_speedTalk.pdf

10:35 Bunch compressor commissioning at ARES

We present the first commissioning results of the movable bunch compressor designed for the ARES linac at DESY. The development and simulated performance has been reported and predicts sub-fs electron bunches with high charge densities. Commissioning results of the injector part of the ARES linac delivered promissing beam quality results to achieve these numbers. The bunch compressor system will be used to bench mark numerical models for coherent synchrotron radiation and space charge for ultra-short electron bunches. Here we will present first measurements of the dispersion management and compensation as well as calculations for the longitudinal dispersion. In the future the Polarix transverse deflecting structure will be commissioned to fully characterize the ARES electron beam.

Speaker: Willi Kuropka (MPY1 (MPY Fachgruppe 1))

ST3ARD_09042022_WK.pdf

10:38 Development of a transferline for LPA-generated electron bunches to a compact storage ring

The injection of LPA-generated beams into a storage ring is considered to be one of the most prominent applications of laser plasma accelerators (LPAs). The Karlsruhe Institute of Technology (KIT) and Deutsches Elektronen-Synchrotron (DESY) cooperate to address the key challenges with the aim to successfully demonstrate injection of LPA-generated beams into a compact storage ring with large energy acceptance and dynamic aperture. The corresponding transfer line is currently being designed within the cSTART project at KIT and will be ideally suited to accept bunches from a 50 MeV LPA prototype developed at DESY. This contribution presents the foreseen layout of the transfer line from the LPA to the injection point of the storage ring and discusses the status of beams optics calculations.

Speaker: Bastian Haerer (Karlsruhe Institute of Technology (KIT))

220907-09_ARD-ST3-Haerer.pdf

10:41 Variable RF Parameters along European XFEL Bunch Trains

Superconducting RF allows for long RF pulses compared to warm normal conducting machines. At the European XFEL these pulses are used to transport up to 2700 bunches to the user stations per pulse.
In order to allow for flexible control of beam properties the LLRF system was modified. We now have the ability to drive the RF pulses very flexible to accommodate either beam based corrections for e.g. energy variations along the train or even introduce advanced FEL delivery modes e.g. variable compression within an experiment.

In this presentation we show the high level controls for daily control room use as well as experiments done at the real machine.

Speaker: Bolko Beutner (MPY (Beschleunigerphysik))

ARD22_beam_regions.pdf

ARD_Beam_Regions.pdf

10:44 Gun5.1 at PITZ: RF conditioning and first characterization

A new generation of normal conducting 1.3GHz RF gun was developed to provide a high-quality electron source for superconducting linac driven free-electron lasers like FLASH and European XFEL. Compared to the Gun4 series, Gun5 aims for a 50% increase of the duration of the RF pulse (up to 1 ms at 10 Hz repetition rate) combined with high gradients (up to ~60 MV/m at the cathode). The first prototype of the new RF gun was manufactured at DESY and installed at the Photo Injector Test facility at DESY in Zeuthen (PITZ) in October 2021. In mid-October 2021 the RF conditioning began, aiming for achieving the aforementioned RF parameters.
The first characterization of Gun5.1 included measurements of RF amplitude and phase stability (pulse-to-pulse and along 1 ms RF pulse). The dark current was measured at various peak power levels. The current status of the RF conditioning will be presented as well as results of the first characterization.

Speaker: Mikhail Krasilnikov (DESY Zeuthen)

ST3speedposterMKgun5_v3.pdf

10:47 Ocean wave impacting arrival time stability at EuXFEL

At X-ray free electron lasers a high temporal stability of produced photon pulses is a key parameter for many classes of experiments using a pump-probe scheme. At the European XFEL an optical synchronization system in combination with beam-based feedbacks guarantees an FEL-to-laser pulse short-term jitter on the sub-10 fs level. However, environmental factors acting on different time scales lead to residual timing drifts between external lasers and FEL pulses and require additional measures to disentangle the overlaid effects. Here, we present results from investigation of drifts induced by ocean waves of the North Sea and the Atlantic Ocean.

Speaker: Dr Marie Kristin Czwalinna (DESY, MSK (Strahlkontrollen))

ARD-ST3_slides_czwalinna.pdf

ARD-ST3_slides_czwalinna.pptx

10:50 → 11:00 Coffee break

11:00 → 12:30 Session 4: Beam Dynamics: Posters

Convener: Michael Kuntzsch (HZDR)

12:30 → 13:00 Farewell

13:00 → 14:00 Take-away lunch

Light lunch with take-away options will be provided for the participants

14:00 → 15:00 Guided tours HZB