Author: Schmidt, Ch.
Paper Title Page
MOOAA03 Fast Feedback Strategies for Longitudinal Beam Stabilization 26
  • S. Pfeiffer, M.K. Bock, H. Schlarb, Ch. Schmidt
    DESY, Hamburg, Germany
  • W. Jałmużna
    TUL-DMCS, Łódź, Poland
  • G. Lichtenberg, H. Werner
    TUHH, Hamburg, Germany
  The key for pump-probe and seeding experiments at Free Electron Lasers such as FLASH is a femtosecond precise regulation of the bunch arrival time and compression. To maintain this beam based requirements, both for a single bunch and within a bunch train, it is necessary to combine field and beam based feedback loops. We present in this paper an advancement of the currently implemented beam based feedback system at FLASH. The principle of beam based modulation of the RF set point can be superimposed by a direct feedback loop with a beam optimized controller. Recent measurements of the achieved bunch arrival time jitter reduction to 20 fs have shown the performance gain by this direct feedback method *. The combination of both approaches will be presented and possible advantages are discussed.
* C. Schmidt et al., “Feedback Strategies for Bunch Arrival Time Stabilization at FLASH Towards 10 fs,” FEL’2011, Shanghai, August 2011, THPA26, http://www.
slides icon Slides MOOAA03 [0.544 MB]  
MOOAC01 The European XFEL LLRF System 55
  • J. Branlard, G. Ayvazyan, V. Ayvazyan, M.K. Grecki, M. Hoffmann, T. Jeżyński, I.M. Kudla, T. Lamb, F. Ludwig, U. Mavrič, S. Pfeiffer, H. Schlarb, Ch. Schmidt, H.C. Weddig, B.Y. Yang
    DESY, Hamburg, Germany
  • P. Barmuta, S. Bou Habib, L. Butkowski, K. Czuba, M. Grzegrzółka, E. Janas, J. Piekarski, I. Rutkowski, D. Sikora, L. Zembala, M. Żukociński
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  • W. Cichalewski, K. Gnidzińska, W. Jałmużna, D.R. Makowski, A. Mielczarek, A. Napieralski, P. Perek, A. Piotrowski, T. Pożniak, K.P. Przygoda
    TUL-DMCS, Łódź, Poland
  • S. Korolczuk, J. Szewiński
    The Andrzej Soltan Institute for Nuclear Studies, Centre Świerk, Świerk/Otwock, Poland
  • K. Oliwa, W. Wierba
    IFJ-PAN, Kraków, Poland
  The European X-ray free electron laser accelerator consists of 800 superconducting cavities grouped in 25 RF stations. The challenges associated with the size and complexity of this accelerator required a high-precision, modular and scalable low level RF (LLRF) system. TheμTCA technology (uTCA) was chosen to support this system and adapted for RF standards. State-of-the-art hardware development in close collaboration with the industry allowed for the system continuity and maintainability. The complete LLRF system design is now in its final phase and the designed hardware was installed and commissioned at FLASH. The uTCA hardware system, measurement results and system performance validation will be shown. Operational strategy and plans for future automation algorithms for performance optimization will also be presented in this paper.  
slides icon Slides MOOAC01 [12.188 MB]