6th ARD ST3 workshop

26 Sept 2018, 09:00 → 28 Sept 2018, 13:00 Europe/Berlin

Seminar room 201, building 114 (HZDR)

Anke-Susanne Mueller (Karlsruher Institut fuer Technologie), Holger Schlarb (DESY), Michael Gensch (HZDR, Institute for Radiation Physics)

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, Helmholtz Zentrum Dresden-Rossendorf (HZDR), Forschungszentrum Jülich (FZJ), Helmholtz Zentrum for Heavy Ion Research GSI in Darmstadt, Karlsruhe Insitute for Technology (KIT), and Helmholtz Zentrum Berlin for Materials and Energy (HZB) ), two Helmholtz institutes, eleven universities, two Max-Planck institutes, and the Max-Born institute. The sixth ARD topical workshop on “ps - fs Electron and Photon Beams” will focus on three fundamental areas of current research in the field of short pulse particle accelerators, namely research related to synchronization and seeding, ultra-fast pulse diagnostics, and photon radiation and interaction. The workshop aims to bring to together scientists from universities and Helmholtz centers that are involved in the subtopic 3 (ST3) “ps – fs Electron and Photon Beams” of the ARD program. It shall 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 ST3.

Wednesday 26 September

Chimera Workshop

slides ChimeraTK_update_Sept2018.pdf

1 Chimera Workshop

Speaker: Martin Killenberg (DESY)

Slides ChimeraTK_update_Sept2018.pdf

Tours to ELBE High Power Radiation Sources

Registration and Welcome

Facility Report

2 Facility Report-HZDR

Speaker: Dr Michael Gensch (HZDR)

Slides ARD_testfacilityTELBEfinal.finalppt.pdf

3 Facility Report -DESY

Speaker: Dr Holger Schlarb (DESY)

Slides ARD-ST3-DESY-Acc_20190926.pptx

4 Facility Report - HIM

Speaker: Dr Florian Hug

5 Facility Report-HZB

Speaker: Dr Paul Goslawski (HZB)

Slides 20180926_ARDST3No1_HZBFacilities_PG_indico.pdf

6 Facility Report - KIT

Speaker: Dr Marcel Schuh (KIT)

Slides 2018-09-26-28_ARD-ST3_Schuh_IBPT.pdf

7 Facility Report - DELTA

Speaker: Carsten Mai (DELTA - TU Dortmund)

14:30 Coffee break

BEAM DYNAMICS

8 Beam Dynamics BESSY VSR

Speaker: Dr Paul Goslawski (HZB)

Slides 20180926_ARDST3No2_BVSR_PG_indico.pdf

9 Ultra-short beams by SINBAD

Speaker: Mr Daniel Marx (DESY)

Slides ARDST3_HZDR_20180926.pdf

Short Talks Speedposter: BEAM DYNAMICS

Poster Session: BEAM DYNAMICS

10 First design studies on a NC CW RF gun for European XFEL

High brightness high-repetition rate (MHz-class) electron source for European free-electron lasers (FELs) upgrade program is under design at the Photo Injector Test facility at DESY, Zeuthen site (PITZ). A normal-conducting (NC) cavity resonating in the VHF band at 216.7 MHz operating in continuous wave (cw) mode is chosen as the backup candidate. The preliminary design studies of the NC cw RF gun was carried out. The cathode gradient and voltage were pushed to 30 MV/m and 860 kV to improve the beam brightness. This poster presents the RF design and optimization of the copper cavity, multipacting simulation, beam dynamics study as well as the mechanical thermal and stress analysis.

Speaker: Dr Guan Shu (DESY)

11 Influence of the chirped electron beam on THz radiation.

As is well known, coherent emission of radiation from ultrarelativistic electron bunches takes place when the duration of the bunches is shorter than the radiation wavelength. In this case, the contributions to the field from all electrons sum up in phase, and the output intensity scales as the square number of electrons in the bunch. In this work, we consider the particular case of coherent emission of radiation from an undulator in THz range. It is often the case that the electron bunch at the entrance of a THz undulator setup, for accelerator-based THz sources, has an energy chirp. We investigate the influence of the energy chirp of an electron bunch on coherent radiation.

Speaker: Dr Sergey Tomin (European XFEL)

12 Influences of Impedances on Longitudinal Beam Dynamics

The beam dynamics in a particle accelerator are influenced by its impedances. In particular at high charge densities, the production of coherent synchrotron radiation is governed by the longitudinal impedance. With Inovesa, an in-house developed simulation tool, it is possible to simulate the dynamics of the longitudinal phase space density inside a storage ring by solving the Vlasov-Fokker-Planck equation. A complex example for an impedance induced effect is the micro-bunching instability, driven by the CSR self- interaction. In general, a precise knowledge of real world impedances and their implications is required. In this contribution, we present systematic studies of the effects of various simplified impedances on the observed longitudinal phase space density.

Speaker: Mr Patrick Schreiber (KIT)

Poster InfluencesOfImpedances_PatrickSchreiber_ARD_ST3_poster.pdf

Slides Speed_PatrickSchreiber.pdf

13 Studies of Longitudinal Dynamics in the Micro-Bunching Instability using Machine Learning

The operation of synchrotron light sources with short electron bunches increases the emitted coherent synchrotron radiation (CSR) power in the THz frequency range. However, the spatial compression leads to complex longitudinal dynamics, causing the formation of micro-structures in the longitudinal bunch profiles. The fast temporal variation and small scale of these micro-structures put challenging demands on their observation. At the KIT storage ring KARA (KArlsruhe Research Accelerator), diagnostics have been developed allowing direct observation of the dynamics by an electro-optical setup, and indirect observation by measuring the fluctuation of the emitted CSR. Additionally, the longitudinal dynamics can be simulated using the numerical Vlasov-Fokker-Planck solver Inovesa. In this contribution, we present studies of the micro-structure dynamics on simulated data. To deal with generated data sets in the order of terabytes in size, we apply the machine learning technique k-means to identify the dominant micro-structures in the longitudinal bunch profiles. Following this approach, new insights on the correlation of the CSR power fluctuation to the underlying longitudinal dynamics can be gained.

Speaker: Mr Tobias Boltz (KIT)

Poster 2018-09-26_ARD-ST3_poster.pdf

Slides 2018-09-26_ARD-ST3_speed_talk.pdf

14 Studies of the Micro-Bunching Instability in the Presence of a Damping Wiggler

At the KIT storage ring KARA (KArlsruhe Research Accelerator), the momentum compaction factor can be reduced leading to natural bunch lengths in the ps range. Due to the high degree of longitudinal compression, the micro-bunching instability arises. During this longitudinal instability, the bunches emit bursts of intense coherent synchrotron radiation in the THz frequency range caused by the complex longitudinal dynamics. The temporal pattern of the emitted bursts depends on given machine parameters, like momentum compaction factor, acceleration voltage, and damping time. In this contribution, the influence of the damping time is studied by utilizing the CLIC damping wiggler prototype installed in KARA as well as by simulations using the Flasov-Fokker-Planck solver Inovesa.

Speaker: Miriam Brosi (KIT)

Poster ard-st3-2018_poster_mbrosi.pdf

Slides ard-st3-annual-workshop-slides-mbrosi.pdf

15 Study of a Superconducting Transverse Gradient Undulator for a Laser Plasma Accelerator-Driven FEL

The application of Laser Wakefield Accelerators (LWFA) is a potential key for realizing extremely compact Free Electron Lasers (FEL) due to an unprecedented high longitudinal electric field inside the laser-driven plasma wave. LWFA-based electron beams exhibit challenging initial conditions in terms of beam divergence and large energy spread. The superconducting transverse gradient undulator (TGU) scheme is a viable option to compensate the challenging properties of the LWFA electron beam to enable FEL amplification. A first test of the TGU was performed in a specially designed cryostat of KIT at liquid helium temperature (4.2 K). The first TGU cooling process to 4.2 K was successful. A preliminary magnet powering test was performed by using one of the two undulator coil. The results of these tests are presented in this contribution.

Speaker: Mr Kantaphon Damminsek (Karlsruhe Institue of Technology)

16 THz afterburner undulator for selective THz control experiments at the European XFEL

Different options for proving intense THz filed for THz pump - X-ray probe experiments at the European XFEL using laser-based and/or accelerator-based techniques are currently discussed. Here we present a concept which is based on a superconducting THz undulator utilizing the spent electron beam of the eV scale linac as an afterburner to produce narrowband, tunable, few-cycle THz pulses with world-record intensities. A challenge to this approach is the very high electron beam energy of up to 17.5 GeV which yield particular requirements for the specific undulator design. In this presentation, we will report the preliminary study of the undulator design for the European XFEL and present the radiation properties including expected pulse energies, spectra, and temporal profiles.

Speaker: Mr Takanori Tanikawa (European XFEL)

17 Towards boosting THz superradiance by ideal model bunch forms at TELBE and the European XFEL

The photon flux of superradiant THz undulator emission is calculated from the square modulus of electron-bunch form factors and single-particle spectra with a start-to-end simulation. In this presentation, we will report some preliminary results for boosting THz pulse energies assuming specific ideal model bunch forms for the case of the TELBE facility and an envisioned future THz afterburner undulator at the European XFEL.

Speaker: Mr Takanori Tanikawa (European XFEL)

Tutorial: High Power Lasers

18 High Power Lasers

Speaker: Dr Ulrich Schramm (HZDR)

Thursday 27 September

DIAGNOSTICS

19 Pulse resolved diagnostics at a real world quasi-cw user facility

Speakers: Dr Bertram Green (HZDR), Mr Tester1 Tester1 (Tester)

Slides ARD-ST3_meeting_2018_talk.pdf

20 Smokerings at XFEL REVISITED

Speaker: Mr Artem Novokshonov (DESY)

Slides Novokshonov.pdf

Short Talks Speedposter: DIAGNOSTICS

10:30 Coffee break

Poster Session: DIAGNOSTICS

21 Application of MicroTCA.4 for Diagnostics at the European XFEL and at FLASH

The accelerators of FLASH and of the European XFEL deliver electron bunches in bursts of several hundred pulses with MHz repetition rates every 100ms. These bunches are distributed between different undulator beamlines to generate FEL pulses with few to hundred femtoseconds temporal width in the soft to hard x-ray regime. To run these high repetition rate FELs a large number of different fast detectors and diagnostics, regulation and feedback systems are required which are to a large extent read out or directly controlled by MTCA.4 hardware. This poster gives a few examples of the different MTCA-related applications implemented at both facilities.

Speaker: Dr Marie Kristin Czwalinna (DESY)

Poster Czwalinna_Poster_MTCA-Applications.pdf

Slides Czw_MTCAapplications_speedposterslideremix.pdf

22 Characterization of THz Detectors using the Tunable Narrowband Source at DELTA

-

Speaker: Carsten Mai (DELTA - TU Dortmund)

Slides 20190927_Speedposter36_Carsten_Mai.pptx

23 Development of a Silicon Strip Detector for the ARES Spectrometer.

In collaboration between DESY MPY-1 and DESY FH ATLAS a silicon strip detector for the ARES spectrometer is being developed. This detector will be used for low (sub-pC) charged beams where a good spatial resolution is needed. It will be placed after the spectrometer dipole. The detector consists of two 1cm x 1cm silicon strip sensors. The readout is done by 4 charge-to-digital converters with three strips grouped together per readout channel. The key specifications of the ATLAS miniatures strip sensors developed for the HL-LH ATLAS tracker upgrade are a pitch of 74.5 micron, 103 strips per sensor and a thickness of 310 microns. Current-Voltage and Capacitance-voltage measurements were performed at the UNI HH lab. Measurement results and a dedicated charge production simulation tool will be presented and discussed in detail. A proof of principle experiment is foreseen at the DESY II test beam at the beginning of 2019.

Speaker: Sonja Jaster-Merz (DESY)

Slides Sonja_Jaster-Merz.pdf

24 FLUTE Diagnostics - Overview and Status

FLUTE (Ferninfrarot Linac- Und Test-Experiment) will be a new compact versatile linear accelerator at KIT. Its primary goal is to serve as a platform for a variety of accelerator studies as well as to generate strong ultra-short THz pulses for photon science. The machine consists of an RF gun, a travelling wave linac and a D-shaped bunch compressor chicane with corresponding diagnostic sections. In this contribution, we give an overview of the diagnostic components used at FLUTE and present their commissioning status.

Speaker: Mr Thiemo Schmelzer (Karlsruhe Intitute of Technology (KIT))

25 Longitudinal electron bunch diagnostics for LWFA based on broadband, spectral CTR measurements at single-shot

Laser-wakefield accelerators (LWFA) feature electron bunch durations on a scale of a few fs. Precise knowledge of the longitudinal profile of such ultra-short electron bunches is essential for the design of future table-top X-ray light sources. The resolution limit, as well as the limited reproducibility of electron bunches, pose big challenges for LWFA beam diagnostics. Spectral measurements of broadband transition radiation from LWFA electron bunches passing through a metal foil are especially promising for analyzing ultrashort longitudinal bunch characteristics ranging from of tens of fs down to sub-fs. Our broadband, single-shot spectrometer combines the TR spectrum in UV/VIS (200-1000nm), NIR (0.9-1.7μm) and mid-IR (1.6-12μm). A complete characterization and calibration of the spectrometer has been done with regard to wavelengths, relative spectral sensitivities and absolute photometric sensitivity. Our spectrometer is able to characterize electron bunches with charges as low as 1 pC and resolve time-scales from 0.4 to 40 fs. We present results from recent measurement campaign by analyzing transition radiation spectra produced by nC class LWFA electron bunches using ionization-injection, while complementary data on the transverse bunch profile is provided by simultaneously imaging the CTR in the far- and near-field. We discuss the data analysis from detection to profile reconstruction with error analysis and show electron bunch profiles as determined from experimental density scan measurements.

Speakers: Dr Alexander Debus (HZDR), Mr Omid Zarini (Helmholtz-Zentrum Dresden-Rossendorf)

Slides Speedtalk slides

26 Novel Si-Sensor technology for KALYPSO system

Linear array detectors with high spatial resolution and MHz frame-rates are essential for high-rate experiments at accelerator facilities. We have developed KALYPSO, a line array detector with 1024 pixels operating at 10 Mfps. To improve the spatial resolution and sensitivity at different wavelengths, novel Si microstrip sensors have been developed with a pitch of 25 μm. Furthermore, to enable measurements of the beam profile with a repetition time of 2 ns, a sensor based on Low Gain Avalanche Detector (LGAD) coupled with a SiGe readout is under development. The detector system and the characterization of the sensors will be presented.

Speaker: Ms Meghana Mahaveer Patil (KIT)

27 On-chip devices for THz based diagnosis

We will introduce the current as well as planned on-chip devices manufactured in standard industrial processes for THz based diagnosis. This includes on-chip spectrometers, multi-element detectors providing spatial information as well as polarization sensitive approaches.

Speaker: Dr Niels Neumann (TU Dresden, Chair for RF and Photonics Engineering)

Slides speedposter_slides_neumann.pdf

28 Status of KIT technology developments for plasma accelerator diagnostics

The poster discusses the technologies currently investigated at KIT as potential diagnostic techniques to explore plasma properties of plasma accelerators. The work is supported by the Helmholtz President’s strategic fund IVF "Plasma accelerators".

Speaker: Dr Erik Bruendermann (KIT)

29 TELBE: Ultra-fast-science enabled by advanced photon diagnostics.

In this contribution we show how the THz photondiagnostic efforts within ARD-ST3 have enabled several scientific breakthrough experiments at the TELBE THz facility

Speaker: Dr Sergey Kovalev (Helmholtz Zentrum Dresden Rossendorf)

30 THz spectral characterization at FLASH1: Lamellar Grating Interferometer

Free Electron Laser in Hamburg (FLASH) employs a unique FEL scheme which provides naturally synchronized X-ray and intense THz pulses, generated from the same electron bunch, enabling the performance of exciting THz-XUV pump-probe experiments. Characterization of the spectrum has a high priority in many experiments. We have designed a spectrometer to characterize the broadband intense THz pulses. Based on the lamellar grating geometry, our home-made FTIR spectrometer operates at frequencies 0.3 - 10 THz, which covers the most efficient range of FLASH1 THz source. We present the recent results and talk about perspectives for the implementation of the spectrometer as online tool at FLASH.

Speaker: Ms Ekaterina Zapolnova (DESY)

31 Towards FPGA-based high speed data aquisition with online analysis

Towards FPGA-based high speed data aquisition with online analysis

Speaker: Mr Mohammed bawatna (HZDR)

12:30 Lunch

SYNCHRONIZATION AND CONTROL

32 Control system design for SRF cavity based on Kalman filter observer

Speaker: Dr Andriy Ushakov (Application engineer)

Slides 2018_v11_ARDST3_AUshakov.pdf

33 LLRF at ELBE

Speaker: Dr Klaus Zenker (HZDR)

Slides ARD_zenker.pdf

34 Sub-10-fs drift stability feedback for the broadband burst-mode OPCPA System at FLASH

Speaker: Tino Lang (FS-LA)

Slides Sub_10-fs_drift_stability_feedback_for_broadband_burst-mode_Schirmel_Lang.pptx

Short Talks Speedposter: SYNCHRONIZATION AND CONTROL

15:00 Coffee break

Poster Session: SYNCHRONIZATION AND CONTROL

35 A new approach to femtosecond level intrinsic synchronization between accelerators and external laser systems

The timing jitter between accelerator-based light sources and external laser systems is nowadays the critical limit for the achievable temporal resolution in ultrafast time-resolved experiments at 4th generation light sources such as superradiant terahertz (TELBE) facilities or X-FEL's. In this work we demonstrate the proof-of-principle experiment. It was experimentally shown that our scheme allow us to compress timing jitter between two laser systems by 2 orders of magnitude, from 2ps to 15fs by utilizing laser induced single cycle THz pulses as gate signal based on electro-optic slicing.

Speaker: Mr Min Chen (Helmholtz - Zentrum Dresden - Rossendorf)

36 CONTROL SYSTEM DESIGN FOR SRF CAVITY BASED ON KALMAN FILTER OBSERVER

Superconducting Radiofrequency Cavities as planned for BESSY-VSR or bERLinPro require a high stable RF field of the accelerating mode in order to allow as for VSR a stable RF beating scheme. Further, to ensure efficient operation at low RF power consumption, these type of cavities are operated at low coupling, i.e. narrow RF bandwidth. Hence, any disturbance to the system by unwanted cavity detuning can finally lead to the worst situation of a beam loss. The modern SRF cavity control system should take into consideration not perfect model of microphonic disturbances, sensor noise and model instabilities as well as the limitation for the number of expensive sensors. To cope with such class of systems the general approach is based on using linear quadratic regulator together with an observer. The optimal observer based on so called Kalman Filter (KF) was tested nowadays as the data processing firmware in a real mTCA equipment. The input is provided by the virtual cavity representing software/hardware debugging complex and the real-time KF response is then examined. The test results shows relatively good correlation between predictable behavior and KF output.

Speaker: Dr Andriy Ushakov (Application engineer)

37 High Precision Field Receiver for RF Controls at Attosecond Level

Up to now the sensitivity of the field detectors for the accelerating cavitites are limited by the LLRF system and actuators to about 3fs for a bandwidth of 1 MHz. The main limitation is using digital field detection schemes, which involves front-ends, LO-generation and analog to digital converters. Within this poster the field detection method based on a suppressed carrier signal is presented. In comparison to the well-known results measured by the LLRF system, most recent results of the measurement technique will be shown.

Speaker: Ms Louise Springer (DESY)

Slides ARDST3_HZDR_18.pptx

38 Large-Scale Optical Synchronization System of the European XFEL

Speaker: Mr Jost Mueller (DESY)

Slides ARDST3_Mueller.pptx

39 Precision X-Band RF control system

The new PolariX TDS cavities developed in cooperation between DESY, PSI and CERN require X-Band RF front-ends for the measurement of the 12 GHz electric fields. The cavity, waveguide and klystron signals will be down-converted from 12 GHz to 3 GHz and further processed in a standard 3 GHz S-Band RF control system based on MicroTCA.4. In this poster, we will present the 9 GHz LO generation method and measurements of the 12 GHz front-end prototype setup. Preliminary results have shown a short-term jitter of about 1.1 fs rms for the LO generation and 1.1 fs rms resolution for the X-Band down-conversion. Further steps concern the PCB integration as well as the discussion of the 19“ chassis packaging.

Speaker: Mr Matthias Reukauff (DESY)

Slides Speedtalk_ARD-ST3_18_MReukauff.pptx

40 Status of the linac-based KIT test facility & THz source FLUTE

Phase 1 of the "Ferninfrarot Linac- und Test-Experiment" (FLUTE), a 41 MeV linear accelerator, is currently in commissioning at KIT. Phase 1 comprises mainly the RF system including the LLRF system, electron gun, gun laser, timing system and various beam diagnostics elements. The current status of the commissioning is given in this contribution.

Speaker: Dr Michael Nasse (Karlsruhe Institute of Technology)

Slides 2018-09-26_28_Speedposter_MT_ARD-ST3_Poster_FLUTE_1stBeam_Nasse.pdf

Tutorial: Vacuum Systems

41 Vacuum Systems

Speaker: Dr Sven Lederer (DESY)

Slides 20180927_ARD-ST3_Vacuum_for_accelerators_SLederer.pdf

18:00 Workshop dinner

Friday 28 September

POF IV talks and discussion

42 POF4 talk-HZDR

Speaker: Pawel Evtushenko (HZDR)

Slides ELBE-Upgrade_ARD-ST3-2018_Evtushenko_20180928.pdf

43 POF4 talk- HZDR

Speaker: Dr Michael Kuntzsch (HZDR)

44 POF4 talk-DESY

Speaker: Dr Holger Schlarb (DESY)

Slides ARD-ST3-DESY-Stategy-POV4_20190928.pdf ARD-ST3-DESY-Stategy-POV4_20190928.pptx

45 POF4 talk-KIT

Speaker: Anke-Susanne Mueller (KIT)

Slides KIT_ARD_Strategy.pdf MT_ST3_POF4.pdf

46 POF4 talk-HZB

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

Slides ARDSTNo3_HZBinPOFIV_indico.pdf

11:00 Coffee break

Close out

47 Close out

Speaker: Dr Holger Schlarb (DESY)

Slides ARD-ST3-Next_Meeting_20190928.pptx