Author: Koprek, W.
Paper Title Page
MOPC153 Design and Implementation of Automatic Cavity Resonance Frequency Measurement and Tuning Procedure for FLASH and European XFEL Cryogenic Modules 439
 
  • V. Ayvazyan, W. Koprek, D. Kostin, G. Kreps
    DESY, Hamburg, Germany
  • Z. Geng
    SLAC, Menlo Park, California, USA
 
  The superconducting cavities in FLASH and European XFEL should be tuned to the frequency of 1.3 GHz after cool down and adjusted to initial frequency before warm up by stepper motor tuners. The initial frequency is 300 kHz far from the operating frequency (1.3 GHz) to remove mechanical hysteresis of the tuner. The cavities should be relaxed to initial frequency to avoid a plastically deformation. In framework of digital low level RF and DOOCS control systems we have developed a simple automatic procedure for the remote resonance frequency measurement and simultaneous remote tuning for all cavities which are driven from the single klystron. The basic idea is based on frequency sweeping both for driving klystron and for generation of local oscillator frequency with constant RF frequency from master oscillator. The developed system has been used during FLASH commissioning in spring 2010 and is in use for cavity and cryogenic module test stands for European XFEL at DESY.