# MT ARD ST3 Annual meeting

Europe/Berlin
Hörsaal (KBW)

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GSI/FAIR campus
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Description
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. As the ARD ST3 will broaden its scope from current “ps – fs Electron and Photon Beams” to “Advanced beam controls, beam diagnostics and beam dynamics” in POF4, the seventh ARD topical workshop for ST3 will be held in GSI from Oct. 16 to 18. In addition to the review of the progress in the three fundamental areas of current research of short pulse particle accelerators, this workshop also aims for bringing the scientists from universities and Helmholtz centers that are involved in the current subtopic 3 (ST3) “ps – fs Electron and Photon Beams” of the ARD program with the scientists who have been and will be in the ST3 POF4 topics. 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 ST3. In addition, the host of GSI colleagues would also like to use this opportunity to share with the community the tremendous progress that FAIR project has made recently!
Participants
• Andrea Bellandi
• Andreas Ebersoldt
• Andreas Jankowiak
• Andreas Penirschke
• Andreas Schwarz
• Annika Eichler
• Bastian Härer
• Benjamin Kehrer
• Bernhard Scheible
• Carsten Mai
• Christoph Hessler
• Erik Bruendermann
• Florian Burkart
• Furkan Ucar
• Georgi Georgiev
• Hamed Shaker
• Holger Schlarb
• Houjun Qian
• Jan Marjanovic
• Jan Timm
• Ji-Gwang Hwang
• Johannes Zink
• Jost Müller
• Klaus Zenker
• Kral Jiri
• Larissa Birli
• Louise Springer
• Ludwig Frank
• Marcel Schuh
• Marie Kristin Czwalinna
• Marten Koopmans
• Matthias Balzer
• Matthias Reukauff
• Meghana Patil
• Mei Bai
• Michael Büchler
• Michele Caselle
• Min Chen
• Miriam Brosi
• Mohammed Bawatna
• Nils Lockmann
• Patrick Nonn
• Patrick Rauer
• Patrick Schreiber
• Paul Goslawski
• Pavel Evtushenko
• Peter Forck
• Petra Schuett
• Raffael Niemczyk
• Rahul Singh
• Sandeep Ummethala
• Shahab Sanjari
• Sonja Jaster-Merz
• Stefano Mattiello
• Stephan Kötter
• Stephan Reimann
• Sven Pfeiffer
• Thiemo Schmelzer
• Thomas Stoehlker
• Vaibhav Jain
• Vera Chetvertkova
• Weijia Wang
• Xiangkun Li
Support
• Wednesday, October 16
• Registration and Welcome Hörsaal

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GSI/FAIR campus
• Facility status talks Hörsaal

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GSI/FAIR campus
• 1
PITZ/FLASH and XFEL at DESY
Speaker: Dr Holger Schlarb (DESY)
• 2
FAIR Project at GSI
Speaker: Jörg Blaurock (GSI)
• 3
FLUTE and KARA at KIT
Speaker: Marcel Schuh (KIT)
• 4
VSR & BerLinPro at HZB
Speaker: Prof. Andreas Jankowiak (HZB)
• 5
ELBE and DALI at HZDR
Speaker: Dr Pavel Evtushenko (HZDR / ELBE)
• 6
S-DALINAC
Speaker: Michaela Arnold
• 3:10 PM
Coffee break Foyer

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• Diagnostics Hörsaal

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GSI/FAIR campus
• 7
Diagnostics for BESSY VSR, an overview
BESSY VSR is an upgrade project of the existing storage ring BESSY II to create long and short photon pulses simultaneously for all beamlines by installing superconducting cavities with harmonic frequencies of 1.5 GHz and 1.75 GHz. The storage-ring operation will be influenced by a transient beam-loading effect of all cavities in accordance with a complex filling pattern. This calls for bunch resolved measurements with sub-ps time resolution and micrometer spatial resolution. Currently, we are constructing a diagnostic platform for visible light as well as THz radiation and establishing not only sensitive and high-resolution beam diagnostics but also other innovative methods for the measurement of bunch-length as well as lateral size. In this presentation, the physical design and preliminary results will be presented.
Speaker: Dr Ji-Gwang Hwang (Helmholtz-Zentrum Berlin)
• 8
Pulse- and field-resolved THz diagnostics at TELBE
In this work we demonstrate an approach of double arrival time monitors (ATM), which is employed to increase synchronization level between external femtosecond laser systems and 4th generation light sources. With comparison to the single arrival time monitor technique, which was routinely used for time-resolved experiments at accelerator-based light sources, here we demonstrate more than twice increase in the temporal resolution and elimination of temporal drifts. The proposed technique opens a way for sub-femtosecond synchronization within large-scale facilities and laser systems.
Speaker: Mr Min Chen (Helmholtz - Zentrum Dresden - Rossendorf)
• 9
Measurements at ELBE with Martin-Puplett interferometer
Speaker: Dr Pavel Evtushenko (HZDR / ELBE)
• 10
High sensitive SCHOTTKY analysis for the GSI storage ring
Speaker: Dr Shahab Sanjari (GSI Darmstadt)
• Speed talks: Diagnostics Hörsaal

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GSI/FAIR campus
• 11
Upgraded Bunch Arrival-Time Monitors for the European XFEL Reaching Below 3fs Time Resolution
Free electron laser facilities, such as the European XFEL and FLASH, have increasingly high demands on the temporal stability of the electron bunches, as pump-probe experiments meanwhile aim for timing stabilities of few femtoseconds residual jitter only. For a beambased feedback control of the linear accelerator, bunch arrival-time monitors are required that are capable of reaching measurement resolutions better than the stated timing stability goals. We report on our electro-optical bunch arrival-time monitors now achieving a time resolution better than 3 fs. This new level of precision is a first step towards the ultimate goal of reaching sub-femtosecond timing stability. The system has also been upgraded to allow for multi-beam line operation with large variations of the bunch arrival times for the different pulse trains. The characteristics of the bunch arrival-time monitor system and limitations of the state-of-the-art design will be discussed.
Speaker: Dr Marie Kristin Czwalinna (DESY)
• 12
Development of a Beam Profile Monitor based on Silicon Strip Sensors for Low-Charge Electron Beams at ARES
Novel accelerator techniques such as dielectric laser acceleration (DLA) will be studied at the SINBAD facility (DESY Hamburg) using the ARES linac. Due to the low charge of the accelerated beams, charge densities below 1 aC per square micron are expected at the spectrometer screen, which are challenging to measure with conventional techniques used in multi-pC accelerators. Therefore, a dedicated beam profile monitor, based on silicon strip sensors originally developed for the ATLAS inner tracker upgrade, was developed to measure these distributions with a sufficient spatial resolution of around 100 micron. Here, the design of the device and experimental tests with a prototype are presented
Speaker: Sonja Jaster-Merz (DESY)
• 13
Bunch-Resolved 2D Measurements at BESSY II
With the VSR upgrade for the BESSY II electron-storage ring bunch resolved diagnostics are required for machine commissioning and to ensure the long-term quality and stability of operation. For bunch-length measurements a dedicated beamline equipped with a fast streak camera was set up and successfully commissioned. The beamline is also capable of direct beam-profile imaging and interferometry of the vertical beam size using the X-ray blocker bar. Optimisations are still ongoing. 2D bunch-resolved measurements with an additional transverse dimension are already possible with the streak camera. First results of 2D bunch-resolved measurements on the “pulse picking by resonant excitation” (PPRE) bunch are presented.
Speaker: Marten Koopmans (HZB)
• 14
Diagnostics for the micro-bunching instability at KARA
At the Karlsruhe Research Accelerator (KARA), the micro-bunching instability is investigated during regular low-alpha runs. Therefore, several diagnostics setups are used for time-resolved and synchronous measurements of the different bunch parameters with the long-term goal to reconstruct the longitudinal phase space. This allows to study the CSR intensity, the bunch length and the horizontal bunch size – as a measure for the energy spread – with a single-turn resolution. In this contribution, we give an overview about the different setups and present first results.
Speaker: Mr Benjamin Kehrer (Karlsruhe Institute of Technology)
• 15
Electron Beam Characterization and Gun Laser Stability at FLUTE
The low energy section of FLUTE (Ferninfrarot Linac- Und Test-Experiment), a compact versatile linear accelerator under construction at the Karlsruhe Institute of Technology (KIT), is currently being commissioned. For the characterization of the electron beam different diagnostics tools are available, such as profile monitors and an energy spectrometer. The electron beam is produced in the photo injector gun using a short-pulse laser. Therefore power and positioning instabilities of the laser beam transfer onto the electron beam. In this contribution we present electron beam measurements and show the newly commissioned stabilization system in the laser transport.
Speaker: Mr Thiemo Schmelzer (Karlsruhe Intitute of Technology (KIT))
• 16
Concept of a novel high-bandwidth arrival time monitor for very low charges as a part of the all-optical synchronization systems at XFEL and FLASH
Numerous advanced applications of X-ray free-electron lasers require pulse durations and time resolutions in the order of only a few femtoseconds or better. The generation of these pulses to be used in time-resolved experiments require synchronization techniques that can simultaneously lock all necessary components to a precision in the range of 1fs only. To improve the experimental conditions at existing facilities and enable future development of seeded FELs, a new all-optical synchronization system at FLASH and XFEL was implemented, which is based on pulsed optical signals rather than electronic RF signals. In collaboration with DESY, Hamburg the all-optical synchronization system is used to ensure a timing stability on the 10fs scale at XFEL. For a future ultra-low charge operation mode down to 1pC at XFEL an overall synchronization of (5+1)fs r.m.s. or better is necessary. This contribution presents a new concept for a ultra-wideband pickup structure for beampipe-diameters down to 10mm for frequencies up to 100GHz or higher and at the same time providing sufficient output signal for the attached EOMs.
Speaker: Mr Bernhard Scheible (Technische Hochschule Mittelhessen)
• 17
Status Update about the PolariX TDS Project
A collaboration between DESY, PSI and CERN has been established to develop and build an advanced modular X-band transverse deflection structure (TDS) system with the new feature of providing variable polarization of the deflecting force. The RF design of such structure, named Polarizable X-band (PolariX) TDS, has been done at CERN, while the fabrication took place at PSI, following the high-precision tuning-free production process. Bead-pull RF measurements on the prototype cavity were also performed at PSI to verify that the polarization of the dipole fields does not have any rotation along the structure. Finally high power test was performed at CERN and now the TDS is at DESY and has been installed in FLASHForward, where the commissioning of the prototype with electron beam is taking place. We summarize in this poster the status of the project and preliminary comment the outcome of the first beamtime for the PolariX commissioning.
Speaker: Mr Matthias Reukauff (DESY)
• 18
Precision X-band RF control system
The new PolariX TDS and its tomographic capabilities will be used in FLASH2, FLASHForward and SINBAD and shall provide a new level of beam diagnostics. It is developed in cooperation between DESY, PSI and CERN and requires 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 LLRF system based on MicroTCA.4. We will present the 9 GHz LO generation method and measurements of the 12 GHz front-end setup as well as an overview of the 19” packaging. Preliminary measurements of a prototype setup have shown a short-term jitter of about 1 fs rms for the LO generation and 1 fs rms resolution for the X-band down-conversion.
Speaker: Mr Matthias Reukauff (DESY)
• 19
Slit-Based Slice Emittance Measurements Optimization at PITZ
At the Photo Injector Test Facility at DESY in Zeuthen (PITZ) photoelectron guns are conditioned and optimized for free-electron laser (FEL) facilities. In order to achieve a high lasing performance an electron beam with low transverse emittance and high current is required. Measurements of the slice emittance are necessary to determine both properties. At PITZ, transverse emittance measurements are carried out with a single-slit scan due to the strong space charge forces at the low momentum of 20 MeV/$c$. Utilizing a transversely deflecting structure (TDS) toghether with quadrupole magnets allows for slice emittance measurements. The poster shows the measurement setup at PITZ, together with methods to calibrate the beam transport and first measurement results.
Speaker: Mr Raffael Niemczyk (PhD Student)
• 20
Virtual Pepper-Pot Technique for 4D Phase Space Studies.
There are ongoing beam coupling studies at the Photo Injector Test facility at DESY in Zeuthen (PITZ). Electron beam asymetries have been observed and gun quadrupoles are installed to correct them. A 4-dimensional phase space characterization is required to understand the asymmetries in detail. A novel technique for 4-dimensional transverse beam phase space measurement is developed at PITZ. This method is called Virtual Pepper-Pot (VPP), because key principles of the pepper-pot mask method are applied. The 4D transverse phase space is reconstructed from a pepper-pot like pattern that is generated by crossing each measured horizontal slit beamlet with all measured vertical slit beamlets. All elements of the 4D transverse beam matrix are calculated and applied to obtain the 4D transverse emittance, 4D kinematic beam invariant and coupling factors. Results of the technique for bunches of 0.5 nC charge are presented.
Speaker: Mr Georgi Georgiev (DESY Zeuthen)
• Poster Session: Diagnostics Hörsaal

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GSI/FAIR campus
• 21
Fast Direct-Sampling Digitizer for RF Accelerator Diagnostics
The rapid development in the field of digitizers is leading to Analog-to-Digital Converters (ADC) with ever higher sampling rates. Nowadays many high-speed digitizers for RF applications and radio communication are available which can sample broadband signals without the need of down converters. These ADCs fit perfectly into beam instrumentation and diagnostic applications like Bunch Arrival time Monitor (BAM) or measuring beam-induced higher-order modes of accelerating cavities. To cover these high- frequency diagnostic applications, DESY has developed a direct sampling FMC digitizer board based on a 12-bit high-speed ADC with an analog input bandwidth of 2.7 GHz. A high-speed direct-sampling data acquisition system capable of acquiring 2 channels at 500 MSP/s will be presented.
Speaker: Mr Johannes Zink (DESY)
• Thursday, October 17
• Beam Dynamics Hörsaal

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GSI/FAIR campus
• 22
Single shot thermal emittance measurement in photoinjectors
Photoinjector is an enabling technology for modern accelerator instruments, and photocathode is one of keys to photoinjector performance. Generally, good photocathode features long life time, high quantum efficiency (QE), low thermal emittance, low dark current, and short response time. While cathode lifetime, QE are routinely monitored, cathode thermal emittance is still a time consuming measurement, thus is not routinely measured. In this contribution, a single shot thermal emittance measurement technique is introduced, and both theoretical basics and experiment results are presented.
Speaker: Mr Houjun Qian (DESY)
• 23
SIS100 beam loss mechanisms and corresponding machine protection
SIS100 is the main accelerator of the FAIR-facility that will provide high-energy high-intensity ions and protons further down to the experiments and production targets. One of the challenges of its operation is the large beam size compared to the physical aperture. This presentation will cover the different beam loss mechanisms in SIS100: resonance crossing due to magnet field errors and space charge, extraction and ionization losses. The corresponding machine protection measures will be discussed, like dedicated warm quadrupoles at extraction section, the halo collimation system and internal beam dump.
Speaker: Dr Vera Chetvertkova (GSI)
• 24
Synchronous Studies of the Longitudinal Micro-Bunching Instability at KARA
Speaker: Miriam Brosi (KIT)
• Speed talks: Beam Dynamics Hörsaal

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GSI/FAIR campus
• 25
Space charge dominated beam transport for THz studies at PITZ
A proof-of-principle experiment for a THz SASE FEL is undergoing preparation at the Photo Injector Test facility at DESY in Zeuthen (PITZ), as a prototype THz source for pump-probe experiments at the European XFEL, which could potentially provide up to mJ/pulse THz radiation while maintaining the identical pulse train structure as the XFEL pulses. One key design is to obtain a peak current of nearly 200 A from the heavily charged bunches of a few nC, which is then sent to an LCLS-I type undulator for THz generation in the SASE regime. Challenges such as the generation, transport and matching of the space charge dominated beam will be addressed in this contribution. Experimental results on the generation, characterization and matching of the beam will also be presented.
Speaker: Dr Xiangkun LI (DESY Zeuthen)
• 26
First Experiences with Negative Momentum Compaction at KARA
For future synchrotron light sources different acceleration modes are of interest including operation with negative momentum compaction. The Karlsruhe Research Accelerator (KARA) is an accelerator test facility that enables the implementation of a wide variety of operation schemes. This possibility is utilised by testing optics with a negative momentum compaction factor at KARA. Studies of collective effects in this regime are being performed with close attention to the head-tail and microbunching instability. In this contribution we will present the status of operation in the negative momentum compaction regime as well as first studies on collective effects.
Speaker: Mr Patrick Schreiber (KIT)
• 27
Status of FLUTE
FLUTE (Ferninfrarot Linac- Und Test-Experiment) is a compact versatile linear accelerator under construction at the Karlsruhe Institute of Technology (KIT). It serves as a platform for a variety of accelerator studies and will generate strong THz pulses for photon science. In the 7 MeV injector section, currently under commissioning, the first experiment is being set up, the Split Ring Resonator (SRR) experiment. It is based on THz streaking using a resonating ring structure to measure the longitudinal electron bunch profile. In this contribution, we report the current status in the commissioning phase of the injector section with focus on the progress of the SRR-Experiment. Furthermore, the progress from the first electron beam, generated at FLUTE, to the current status will be presented.
Speaker: Mr Thiemo Schmelzer (Karlsruhe Intitute of Technology (KIT))
• 10:30 AM
Coffee break Foyer

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• Poster Session: Beam Dynamics Hörsaal

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GSI/FAIR campus
• 28
PITZ Optimization at SRF Gun Gradients
A continuous wave (CW) mode operation of the European XFEL is under studies for a future upgrade. A superconducting RF (SRF) CW gun is under experimental development at DESY in Hamburg. Beam dynamics simulations for this setup have been done assuming 100 pC bunch charge and a maximum electric field at the photocathode of 30-40 MV/m. Experimental studies for these parameters using a normal conducting RF gun have been performed at the Photo Injector Test facility at DESY in Zeuthen (PITZ) together with corresponding beam dynamics simulations. The beam transverse emittance was minimized by optimizing the main photo injector parameters in order to demonstrate the feasibility of generating electron beams with a beam quality required for successful CW operation of the European XFEL for conditions similar to the SRF gun setup.
Speaker: Dr Xiangkun LI (DESY Zeuthen)
• 29
Pulse Shaping Methods for laser-induced Generation of THz Radiation at the DELTA storage ring
At DELTA, a 1.5-GeV electron storage ring operated as a synchrotron light source by the TU Dortmund University, a dedicated beamline is used for experiments with (sub-)THz radiation. Here, an interaction of short laser pulses with electron bunches gives rise to coherently emitted broadband as well as tunable narrowband radiation from 75 GHz to 5.6 THz. For the narrowband operation of the source, a laser pulse with periodic intensity modulation is used. An interferometric approach, the chirped-pulse beating technique, is routinely employed for this purpose. Recently, pulse shaping techniques using spatial light modulators are investigated to gain more flexible control of the laser pulse shape and the spectrotemporal properties of the resulting THz pulses.
Speaker: Carsten Mai (DELTA - TU Dortmund)
• 30
The ARES LINAC at DESY - status update
The ARES linac (Accelerator Research Experiment at DESY) setup hosts a normal conducting RF photoinjector generating a low charge electron beam that is afterwards accelerated by an S-band linac section. The linac as well as a magnetic chicane allow the production of ultrashort pulses with an excellent arrival-time stability. The electron beam has then the potential to serve as a test beam for next generation compact acceleration schemes. The poster reports on the current status of the ARES RF commissioning, linac setup and stages of the upgrade plans.
Speaker: Dr Florian Burkart (DESY)
• 31
Evaluating a Fit Method for an Online Orbit-Response-Matrix Model at DELTA
At DELTA, a 1.5-GeV electron storage ring operated by the TU Dortmund University, preliminary tests of an online orbit-response-matrix model were conducted. Closed orbit perturbations corrected by the slow orbit feedback can be buffered and used to update a fit of the bilinear-exponential model with dispersion (BE+d model). This model is a representation of the orbit-response matrix depending on the beta functions, the betatron phases and the tunes in both planes and an unnormalized dispersion. After a new fitting recipe had been introduced to obtain estimates of the aforementioned quantities, this work focuses on investigating the measurement-over-measurement error of the fitted beta functions. The unnormalized dispersion output is also evaluated. The presented research is based on measurement results.
Speaker: Mr Stephan Kötter (Zentrum für Synchrotronstrahlung (DELTA), TU Dortmund University)
• 32
Bunch Profile Reconstructions based on THz Spectroscopy at EuXFEL
At the European X-ray Free-Electron Laser, the spectral intensity of coherent diffraction radiation emitted at a screen with an aperture is monitored by a single-shot THz spectrometer. The spectrometer covers the range from 0.7-60 THz, which enables longitudinal form factor measurements of the electron bunch at the final compression stage. Iterative phase retrieval algorithm are used to obtain the missing phase information in the frequency domain for bunch current profile reconstructions. As the electron bunch passes through the aperture without any disturbance and the detector system of the spectrometer allows for MHz readout rates, all bunches inside the bunch train can be characterized non-invasively and simultaneously to FEL operation. This contributions describes form factor measurements along the bunch train and shows the resulting current profiles.
Speaker: Nils Lockmann (DESY)
• 33
A Policy Gradient Platform Baseded on ZYNQ Ultrascale+ for Beam Diagnostic
The KIT (Karlsruhe Institute of Technology) storage ring KARA (Karlsruhe Research Accelerator) aims at the stabilization of the emitted THz radiation to tackle the problem of micro-bunching instability. A reinforcement learning based method are planed to be implemented through a RF feedback system located at storage ring. IPE (Institute of Data Processing and Electronics) developed a reinforcement learning hardware platfrom for the final realistic approach in this paper. To provide a proof of concept, a CartPole problem environment are built on a ZYNQ MPSoC platfrom, a fast Neural Network inferance are deployed on FPGA, and a Lite-Weighted training process are developed on ARM. The problem is solved by Policy Gradient method, showing the same functionality with simulation on standard PC and improve dramatically the inferance and training speed. The platform could also used by other reinforcement learning based applications senario.
Speaker: Weijia Wang (Karlsruhe Institute of Technology (KIT))
• 34
The European XFEL photocathode laser
We present the design, performance and long-term stability of the hybrid Yb:fiber, Nd:YVO4 laser used to generate electrons from the RF photocathode gun at the European XFEL facility. The laser provides deep UV output pulses in 600µs long bursts with variable internal repetition rate ranging from 564kHz to 1.1285MHz up to 4.5MHz. Due to its robust laser architecture, comprised of a mode-locked and synchronized fiber oscillator, Yb:fiber amplifiers and Nd:YVO4 gain blocks, the laser has operated with >99% uptime since January 2017. Using this laser, the XFEL reported landmark electron beam energies of 17.5 GeV in July 2018, and simultaneous multi-mJ lasing in its three SASE beamlines. The XFEL photocathode laser offers two parallel outputs (1064nm) with single pulse energies of >100µJ and 11ps width (FWHM). One output is converted to the deep UV (266nm) with conversion efficiencies > 25%. The second beam is sent to a laser heater to reduce microbunching instabilities, increasing the SASE efficiency. For efficient XFEL operation several state-of-art laser controls were implemented, such as: feed-forward algorithm to flatten electron charge along the bunch, active beam stabilization with < +/-10µm beam pointing jitter at the photocathode, state machines for hands-off end-user operation, temporal pulse synchronization and drift compensation, which reduce the timing jigger of the electron bunches to less than 45fs.
• 35
Photocathode Laser for X-ray FELs at DESY with Flexible Pulse Shape
The photocathode laser plays an important role for X-ray Free Electron Laser (XFEL) operation since the generated electron clouds at the gun determine many of the X-ray parameters. Its energy and pointing stability is a pre-requisite for stable X-ray pulse trains. The XUV FEL FLASH at DESY runs in burst-mode, where XUV pulses are emitted in 800 µs long bursts with up to 1MHz intra-burst pulse-repetition rate and 10 Hz burst repetition rate. Each burst of accelerated electron bunches is temporal split into two undulator beamlines, each of them serving multiple science experiments. Different FEL operation modes require optimized electron charge distributions at the electron gun and therefore different photocathode laser pulse shapes. Two extreme requirements are (1) large flat-top beam sizes with long pulse durations (20 ps) for high X-ray pulse energies and (2) short pulse duration (1 ps), small beam sizes for the shortest X-ray pulses (10fs). Currently those different pulse durations are realized by separate photocathode laser systems. Here we present a new photocathode laser design, providing flexible UV pulse durations from 1 ps to 20 ps and single pulse 257nm pulse energies up to 10 μJ at 1 MHz pulse repetition rate.
• 12:15 PM
GSI Tour 1 Hörsaal

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GSI/FAIR campus
• 12:15 PM
Lunch
• 1:00 PM
GSI Tour 2 Hörsaal

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GSI/FAIR campus
• Controls/Seeding/DAQ Session Hörsaal

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GSI/FAIR campus
• 36
Femtosecond synchronization system of the European XFEL
Speaker: Mr Jost Mueller (DESY)
• 37
X-ray FEL Oscillator for the EuXFEL
Speaker: Mr Patrick Rauer (Universität Hamburg)
• 38
SIS100 longitudinal feedback cavity system
Speaker: Harald Klingbeil
• Speed talks: Controls/Seeding/DAQ Session Hörsaal

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GSI/FAIR campus
• 39
Status Update of TARLA and NICA LLRF Projects
The Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) is the first particle accelerator facility under construction in Turkey. The accelerator will deliver electrons to generate gamma radiation via Bremsstrahlung as well as to drive an IR-FEL. It consists of normal conducting and superconducting cavities. The MicroTCA Technology Lab is developing a turn-key LLRF system for this accelerator. The Nuclotron-based Ion Collider fAcility (NICA) at the Joint Institute for Nuclear Research in Dubna, Russia is a synchrotron that delivers light and heavy ions for collision experiments. The Light Ion Linac (LILAC) is the injector for (polarized) protons and deuterons. Its cavities will be designed and delivered by BEVATECH, Frankfurt. The MicroTCA Technology Lab has designed the LLRF system for those cavities in cooperation with BEVATECH. These two projects and their current status will be presented in this poster.
Speaker: Dr Patrick Nonn (DESY)
• 40
Connecting MicroTCA Crates with High Performance Computers via PCIexpress Uplink
The power consumption of a MicroTCA.4 slot is limited to 80 W. This limits the performance of CPUs, used in MicroTCA.4 crates. One option to circumvent this limitation, is to extend the PCI express bus of the crate to a high performance computer, instead. This poster will present the experience gained with such a setup. It will further discuss some of the pros and cons of this setup in comparison to the classic CPU-AMC.
Speaker: Dr Patrick Nonn (DESY)
• 41
Device error handling in ChimeraTK
ChimeraTK is a tool kit to write application servers for control systems. When integrating the devices into a control system, the device servers usually contain a large fraction of error handling code. Many of these errors are runtime errors which occur when communicating with the hardware, and have similar handling strategies. We report how ChimeraTK introduces a standardized way to raise and report errors, and to do the re-initialization when recovering from an error. All this is handled in the framework, which significantly simplifies the business logic because it is not mixed with error handling code any more.
Speaker: Jan Timm (DESY)
• 42
Update on GigE Vision implementation in FPGA
Presented here are the latest updates from the development of the GigE Vision in MicroTCA. First we present the results of the certification process at AIA plug-fest, where our implementation had to interface with cameras from several vendors. A new hardware platform (Struck SIS8160 - an Advanced Mezzanine Card for MicroTCA platform) was also added to the list of supported hardware. With two 64-bit wide DDR4 memories this board offers a good platform for data intensive application, and with the support for White Rabbit is also allows timestamping of the captured frames. Lastly we present the steps needed to extend the support for 10 GigE Vision, based on 10 Gigabit Ethernet.
Speaker: Mr Jan Marjanovic (DESY)
• 3:30 PM
Coffee break Foyer

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• Poster Session: Controls/Seeding/DAQ Hörsaal

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GSI/FAIR campus
• 43
An ultra-fast and wide-spectrum linear array detector for high repetition rate and pulsed experiments
The photon science research at accelerators is influenced radically by the developments of sensor and readout technologies for imaging. It covers a wide range of applications fields both beam diagnostic and user systems, tomography and spectroscopy, etc. The repetition rate of commercially available linear array detectors is a limitation factor for the emerging synchrotron applications. To overcome these limitations, KALYPSO (Karlsruhe Linear arraY detector for MHz rePetition rate SpectrOscopy), an ultra-fast and wide-field of view linear array detector operating at several Mfps, has been developed. A silicon micro-strip sensor is connected to the cutting-edge and custom designed front end ASICs to achieve unprecedented frame rate in continuous readout mode. The system is optimized for near infrared, visible and near ultraviolet spectra regions. The third generation of KALYPSO will be presented. It consists of a linear array sensor with 1024 pixels, operating over 1 Mfps. The detector is currently employed in synchrotron facilities for beam diagnostics, but also has attractive applications for user beam monitor and laser characterizations.
Speaker: Ms Meghana Mahaveer Patil (KIT)
• 44
Development of an FMC+ carrier in MicroTCA
The ecosystem of FMC/FMC+ carriers in MicroTCA (Advanced Mezzanine Card form factor) is very diverse. The requirements for such a board are very demanding, and sometimes even opposing to each other. The definition of a set of requirements that will satisfy most of the use cases is a challenging task. Presented here is the DAMC-FMC2ZUP, a modern and high-performance FMC+ carrier in AMC form factor, hosting a Xilinx Zynq UltraScale+ MPSoC. The FPGA has a total of 52 transceivers (32 GTH, 16 GTY, 4 GTR) providing support to the diverse communication interfaces towards the FMC slots, backplane and RTM. The four cores ARM processor with Mali graphics, and the availability of DisplayPort and USB interfaces over USB type-C allow to use the board in stand-alone mode. The board is fully backward compatible with DAMC-FMC25, an FMC carrier based on two-FPGA solution, with Virtex-5 and Spartan-6. There are two firmware projects already available for the board. The first one contains support for all peripheral components and can serve as a reference design for custom projects. The second one contains the Intellectual Property (IP) cores to support two DFMC-DS500/800 FMC mezzanines, providing a digitizer solution with 4 channels, 12 bits and up to 800 MSPS. Mounting two DFMC-4SFP+ creates a solution with 8 SFP+ connections on the front panel, each one able to communicate at data rates of 10 Gbit/s and higher. DAMC-FMC2ZUP is a versatile platform ideal to perform control tasks around a particle accelerator. Combined with the modularity of the MicroTCA platform it can be a building block for a larger system.
Speaker: Mr Jan Marjanovic (DESY)
• 45
High-Speed Data Acquisition System and Real-time Data Processing using FPGA Architecture
The superradiant THz sources at TELBE facility is based on the new class of accelerator-driven terahertz (THz) radiation sources that provide high repetition rates up to 13 MHz, and flexibility of tuning the THz pulse form. The THz pulses are used for the excitation of materials of interest, about two orders of magnitude higher than state-of-the-art tabletop sources. Time-resolved experiments can be performed with a time resolution down to 30 femtoseconds (fs) using the novel pulse-resolved Data Acquisition (DAQ) system. However, the increasing demands in improving the flexibility, data throughput, and speed of the DAQ systems motivate the integration of reconfigurable processing units close to the new detectors to accelerate the processing of tens of GigaBytes of data per second. In this poster, we introduce our online ultrafast DAQ system that uses an FPGA architecture for real-time image processing, as well as interfacing the image sensors and provide a continuous data transfer.
Speaker: Mr Mohammed bawatna (HZDR)
• 46
Status of the ELBE femtosecond synchronization system
- Overview of the Optical and Control Setup of the pulsed optical synchronization system at ELBE - Results of performance measurements of the system done in 2019 - Actual Goals and Challenges
Speaker: Andreas Schwarz (Helmholtz-Zentrum Dresden-Rossendorf, radiation source ELBE)
• 47
A picosecond sampling system for continuous sampling of ultra-short pulses generated by THz-detectors
This poster presents the 2nd version of the Karlsruhe Pulse Taking Ultra-fast Readout Electronics (KAPTURE-2) for continuous sampling of ultra-short pulses generated by terahertz (THz) detectors. KAPTURE-2 is able to sample each pulse with 4 to 8 sampling points with a resolution of down to 1 ps and accepts flexible pulse repetition rates in a range from 0.2 to 3.6 GHz. Low noise combined with wide dynamic range and bandwidth enables the sampling of signals generated by various GHz- and THz-detectors. To manage the high raw data rate of about 120 Gb/s, KAPTURE-2 is connected to a heterogeneous FPGA-/GPU-based readout system. FPGA and GPU are connected by a new Direct Memory Access (DMA) concept, called ”GPUDirect”. The readout card is equipped with a Xilinx Virtex-7 FPGA and is connected to the GPU by a PCIe Gen 3 x16 data link, capable of a net throughput of up to 13 GB/s. In a traditional DMA architecture, data is first transferred to the main system memory and afterwards moved to the GPUs for processing. Here, the main memory is involved in several read/write operations, depending on the specific implementation. The total throughput and latency of the system is therefore limited by the memory bandwidth. Using the ”GPUDirect” communication, the DMA engine has a direct access to the GPU memory. Therefore latency and hardware requirements of the system are extremely reduced. The GPU real-time architecture is used for pulse reconstruction based on the 4 to 8 sampling points. It results in the peak amplitude of each pulse and the time between two consecutive pulses/buckets with a picosecond time resolution. With KAPTURE-2 it is possible to study THz behavior with an unprecedented temporal resolution and to resolve bunch-to-bunch interactions.
Speaker: Mr Andreas Ebersoldt (KIT)
• 48
Status of CW cryomodule testing at Cryo Module Test Bench.
Cryo Module Test Bench (CMTB) is a facility at DESY to perform Continuous Wave (CW) and pulsed tests on European XFEL cryomodules. The facility is equipped with a 120 kW Inductive Output Tube (IOT), and more than 180 W of cryogenic power at 2 K can be used for the tests. Since last Summer, a new accelerating module, namely XM50.1, is installed at CMTB. Such a device is the first production European XFEL module to be tested in CW. Such a module is equipped with eight superconducting TESLA cavities that are driven with a vector sum scheme. These tests are essential to define the operational constraints and validate technologies for the proposed European XFEL CW upgrade. Of particular importance is the mitigation of microphonic related effects to lower the RF power requirements. Such a task is achieved using an Active Noise Controller (ANC) that uses piezo actuators to reduce the mean square detuning of each cavity. Another effect of interest is the RF-induced heating of the cavity couplers that make the Q_{ext} drift over time. Then a proper characterization of this effect is useful to optimize the RF power consumption of the accelerating system. Other important tests that are ongoing or foreseen at CMTB include the online detection and measurement of quenches and detuning, the characterization of Q0 at different cryogenic temperatures, and the achievable field regulation using RF feedback.
Speaker: Sven Pfeiffer (DESY)
• 49
Field Detection using Carrier Suppression in the Attosecond Regime for CW Signals
Latest free electron lasers (e.g. the EuropeanXFEL) produce x-ray light pulses of below 100fs duration. For this type of accelerator a most precise field detection is required to control the accelerating field inside the superconducting RF cavities. Latest low level RF (LLRF) controls, which are working with the non-IQ detection scheme, are limited to a few femtosecond timing jitter resolution and a noise floor of -150 dBc/Hz to -160 dBc/Hz, typically. A nearly invincible boundary for digital LLRF regulation systems is the limited noise spectral density of available ADCs. Possible solutions to overcome this issue in field detection are named and one promising answer to the problem is explained in detail: A detection scheme based on the suppression of the carrier signal (Carrier Suppression Interferometer, abbr. CSI) is implemented as a receiver front-end for the LLRF MicroTCA.4 standard at DESY. First measurements under laboratory conditions were promising with a noise floor of -184dBc/Hz and below 90as integrated timing jitter in a bandwidth of 20kHz. The next step is the system implementation for CW-operation in the field at CMTB (DESY). For this, all mechanical devices need to be characterized on the sub-as scale and exchanged by electronically controlled devices with an automated carrier suppression algorithm. First results will be presented and discussed.
Speaker: Ms Louise Springer (DESY)
• 50
Ultra-fast arrival time feedback using BACCA at FLASH
The longitudinal intra-bunch train beam-based feedback is used to correct arrival time fluctuations of the electron bunches at the free-electron laser in Hamburg (FLASH). The arrival time information is measured by a bunch arrival time monitor (BAM). The novel bunch arrival corrector cavity (BACCA) has been successfully commissioned and characterized. BACCA is a normal conducting RF cavity, located prior to the first bunch compressor, and acts as ultra-fast energy corrector. Due to the energy dependent path length through the magnetic chicane of the bunch compressor the cavity is used to stabilize the bunch arrival time. This fast energy corrector cavity acts together with the superconducting RF cavities for larger corrections in an intra-train beam-based feedback system. First measurements at FLASH show arrival time stabilities towards 5 fs (rms).
Speaker: Sven Pfeiffer (DESY)
• 51
Scaling Performance in MicroTCA.4
In the past two decades, radio-frequency (RF) controls have improved by two orders in magnitude achieving meanwhile sub-10 fs phase stabilities and 0.01% amplitude precision. Advances are through improved field detection methods and extensive usage of digital signal processing on very powerful field programmable gate arrays (FPGAs). Still the dominant limitation are todays available ADCs. One general approach to overcome this is the brute-force parallelization of receivers, preferable in standards like MicroTCA.4. In this poster we present a proposal for channel parallelization in MicroTCA.4 and hybrid options between conventional and carrier suppression interferometer receivers to achieve sub-fs resolutions.
Speaker: Dr Frank Ludwig (DESY)
• Tutorial Hörsaal

### Hörsaal

#### KBW

GSI/FAIR campus
• 52
Tutorial: Basics of feedback control systems
Speaker: Sven Pfeiffer (DESY)
• 7:00 PM
Conference Dinner GSI cantine

### GSI cantine

#### KBW

GSI/FAIR campus
• Friday, October 18
• Tutorial Hörsaal

### Hörsaal

#### KBW

GSI/FAIR campus
• 53
Tutorial: Beam Diagnostics
Speaker: Peter Forck
• Transition to POF IV Projects in ST2 and ST3
• 54
Topic Structure ARD POFIII/POFIV
Speaker: Prof. Andreas Jankowiak (HZB)
• 55
ARD-ST3
Speaker: Anke-Susanne Mueller (KIT)
• 56
ARD-ST3
Speaker: Dr Holger Schlarb (DESY)
• 57
ARD-ST3
Speaker: Prof. Mei Bai
• 11:00 AM
Coffee break Foyer

### Foyer

#### KBW

• Transition to POF IV Projects in ST2 and ST3
• 58
ARD-ST3
Speaker: Dr Paul Goslawski (Helmholtz-Zentrum Berlin, HZB)
• 59
ARD-ST3
Speaker: Dr Pavel Evtushenko (HZDR / ELBE)
• 60
BMBF Verbundforschung and beyond
Speaker: Dr Erik Bruendermann (KIT)
• 61
DTS activities connecting to ARD-ST3
Speaker: Dr Michele Caselle (KIT)
• 62
Discussion