Author: Pfeiffer, S.
Paper Title Page
WEPME065 European XFEL RF Gun Commissioning and LLRF Linac Installation 2427
 
  • J. Branlard, G. Ayvazyan, V. Ayvazyan, Ł. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, S. Pfeiffer, H. Schlarb, Ch. Schmidt, H.C. Weddig, B.Y. Yang
    DESY, Hamburg, Germany
  • S. Bou Habib, K. Czuba, M. Grzegrzółka, E. Janas, J. Piekarski, I. Rutkowski, R. Rybaniec, D. Sikora, L.Z. Zembala, M. Żukociński
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  • W. Cichalewski, D.R. Makowski, A. Mielczarek, P. Perek, A. Piotrowski, T. Pożniak
    TUL-DMCS, Łódź, Poland
  • S. Korolczuk, I.M. Kudla, J. Szewiński
    NCBJ, Świerk/Otwock, Poland
  • K. Oliwa, W. Wierba
    IFJ-PAN, Kraków, Poland
 
  The European x-ray free electron laser (XFEL) is based on a 17.5 GeV super conducting pulsed linac and is scheduled to deliver its first beam in 2016. The first component of its accelerator chain, the RF gun, was installed in fall of 2013 and its commissioning is underway. This contribution gives an update on the low level radio frequency (LLRF) system development and installation for the XFEL. In particular, the installation, performance and conditioning results of the RF gun are presented. The subsequent steps toward LLRF components mass-production, testing and installation for the XFEL linac are also explained.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME065  
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WEPME075 Real-time Estimation of Superconducting Cavities Parameters 2456
 
  • R. Rybaniec
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  • V. Ayvazyan, J. Branlard, Ł. Butkowski, S. Pfeiffer, H. Schlarb, Ch. Schmidt
    DESY, Hamburg, Germany
  • W. Cichalewski, K.P. Przygoda
    TUL-DMCS, Łódź, Poland
 
  Performance of accelerators based on the superconductive cavities including FLASH and XFEL facilities at DESY is affected by cavity parameters variation over time. High gradient electromagnetic field inside cavities causes detuning due to the Lorentz force. In addition the quality factor of cavities can change during the RF field pulse. Currently used method for estimation of those parameters is based on the post-processing of the data recorded during operation of the RF. External servers calculate cavity parameters using cavity equation, forward power and probe signals collected during previous pulse. A novel approach* based on the component implemented in FPGA is presented. In the new method loaded quality factor and detuning are estimated in real-time during the RF pulse for increased reliability and better exception handling. Modified firmware of the LLRF control system based on the Micro Telecommunications Computing Architecture (MTCA) platform has been used for the method verification.
*”Development of Control System for Fast Frequency Tuners of Superconducting Resonant Cavities for FLASH and XFEL Experiments”, K. Przygoda, PhD thesis, Technical University of Łódź, Poland, 2010.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME075  
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THPRI033 Design of New Buncher Cavity for Relativistic Electron Gun for Atomic Exploration – REGAE 3840
 
  • M. Fakhari, H. Delsim-Hashemi, K. Flöttmann, M. Hüning, S. Pfeiffer, H. Schlarb
    DESY, Hamburg, Germany
  • J. Roßbach
    Uni HH, Hamburg, Germany
 
  The Relativistic Electron Gun for Atomic Exploration, REGAE, is a small electron accelerator build and operated at DESY. Its main application is to provide high quality electron bunches for time resolved diffraction experiments. The RF system of REGAE contains different parts such as low level RF, preamplifier, modulator, phase shifter, and cavities. A photocathode gun cavity to produce the electrons and a buncher cavity to compress the electron bunches in the following drift tube. Since the difference between the operating mode of the existing buncher and its adjacent mode is too small, the input power excites the other modes in addition to the operating mode which affects the beam parameters. A new buncher cavity is designed in order to improve the mode separation. Furthermore the whole cavity is modeled by a circuit which can be useful especially during the tuning process. Beam dynamics simulations have been performed in order to compare the new designed cavity with the old one which declare that the effects of the adjacent modes on the beam parameters are decreased.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI033  
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