Author: Schlarb, H.
Paper Title Page
TUCO03
Upgraded Bunch Arrival-Time Monitors for the European XFEL Reaching Below 3fs Time Resolution  
 
  • M.K. Czwalinna, C. Gerth, H. Schlarb, B. Steffen
    DESY, Hamburg, Germany
 
  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 beam-based 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.  
slides icon Slides TUCO03 [2.481 MB]  
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TUPP002 Direct-Sampling Coarse Bunch Arrival Time Monitor in the Free Electron Laser FLASH Based on the Fast Digitizer Implemented in the FMC VITA 57.1 Standard 270
 
  • J. Zink, M.K. Czwalinna, M. Fenner, S. Jabłoński, J. Marjanovic, H. Schlarb
    DESY, Hamburg, Germany
  • F. Gerfers
    Technische Universität Berlin, Berlin, Germany
 
  At the free-electron lasers FLASH and European-XFEL bunch arrival times are monitored with a high-accuracy electro-optical based data acquisition system (BAM). Due to only a couple of picoseconds time measurement range of this system, large timing changes might cause the monitor to fail. To remove any ambiguity and for health status monitoring a high-speed direct-sampling FPGA mezzanine card (FMC) and an analogue RF front-end was added. The circuitry has lower precision than the electro-optical based BAM, but it can determine bunch arrival time with respect to a reference signal over a large time range, i.e. of the order of 1 ms. After restarts or larger energy changes during operation, the electron bunch arrival time may have been changed by tens or even hundreds of picoseconds, which causes that the BAM is out of its operation range and needs to be recalibrated. With the solution developed, the BAM gets the coarse bunch timing from the digitizer and adjusts its optical delay lines accordingly. This allows for finding the operation point fast and automatically. Performance data of the fast direct-sampling digitizer FMC and first measurement data from FLASH will be presented.  
poster icon Poster TUPP002 [3.810 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP002  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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WEPP018 THz Generation by Optical Rectification for a Novel Shot to Shot Synchronization System Between Electron Bunches and Femtosecond Laser Pulses in a Plasma Wakefield Accelerator 548
 
  • S. Mattiello, A. Penirschke
    THM, Friedberg, Germany
  • H. Schlarb
    DESY, Hamburg, Germany
 
  Funding: The work of S. Mattiello is supported by the German Federal Ministry of Education and Research (BMBF) within the Project ’ MAKE-PWA.
We investigate the influence of the optical properties and of the theoretical description of the THz generation on the conversion efficiency of the generation of short THz pulses. The application is a feedback-system for SINBAD with a time resolution of less than 1 fs for the synchronization of the electron bunch and of the plasma wake field in a laser driven plasma particle accelerator*. Here stable THz pulses are generated by optical rectification of a fraction of the plasma generating high energy laser pulses in a nonlinear lithium niobate crystal. Then the generated THz pulses will energy modulate the electron bunches shot to shot before the plasma to achieve the required time resolution. In this contribution we compare different approximations for the modeling of the generation dynamics using second order or first order equations as well as considering pump depletion effects. Additionally, the dependence of the efficiency of the THz generation on the choice of the dielectric function has been investigated.
*The feedback system will be tested at the Accelerator R&D facility SINBAD (Short Innovative Bunches and Accelerators at DESY).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP018  
About • paper received ※ 04 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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WEPP019 Concept of a Novel High-Bandwidth Arrival Time Monitor for Very Low Charges as a Part of the All-Optical Synchronization System at ELBE 553
 
  • A. Penirschke
    THM, Friedberg, Germany
  • W. Ackermann
    TEMF, TU Darmstadt, Darmstadt, Germany
  • M.K. Czwalinna, H. Schlarb
    DESY, Hamburg, Germany
  • M. Kuntzsch
    HZDR, Dresden, Germany
 
  Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) under contract no. 05K19RO1.
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 a few fs only. The CW operated electron accelerator ELBE at the Helmholtzzentrum Dresden Rossendorf uses a all-optical synchronization system to ensure a timing stability on the few 10 fs scale. ELBE requires a minimum beam pipe diameter of 43mm that limits the achievable output voltage of the pickup structure to drive the attached electro-optical modulator. This contribution presents a concept for a novel high-bandwidth arrival time monitor with sufficient output signal for the attached EOMs for very low charges as a part of the all-optical synchronization system at ELBE.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP019  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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WEPP020 First results on Femtosecond Level Photocathode Laser Synchronization at the SINBAD Facility 557
 
  • M. Titberidze, M. Felber, T. Kozak, T. Lamb, J. Müller, H. Schlarb, S. Schulz, C. Sydlo, F. Zummack
    DESY, Hamburg, Germany
 
  SINBAD, the "short-innovative bunches and accelerators at DESY" is an accelerator research and development facility which will host various experiments. SINBAD-ARES linac is a conventional S-band linear accelerator which will be capable of producing ultra-short electron bunches with duration of few femtoseconds and energy of up to 100 MeV. In order to fully utilize the potential of ultra-short electron bunches while probing the novel acceleration techniques (e.g. external injection in LWFA), it is crucial to achieve femtosecond level synchronization between photocathode laser and RF source driving the RF gun of the ARES linac. In this paper we present the first results on the synchronization of the near-infrared photocathode laser to the RF source with the residual timing jitter performance of ~10 fs rms. These results were obtained using a conventional laser-to-RF synchronization setup employing heterodyne detection of an RF signal generated by impinging the laser pulses to a fast photodetector. In addition, we describe an advanced laser-to-RF phase detection scheme as a future upgrade; promising even lower timing jitter and most importantly the long-term timing drift stability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP020  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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