A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z  

Hoffmann, M.

Paper Title Page
MOPAN019 Performance of the New Master Oscillator and Phase Reference System at FLASH 188
 
  • S. Simrock, M. Felber, M. Hoffmann, B. Lorbeer, F. Ludwig, H. C. Weddig
    DESY, Hamburg
  • K. C. Czuba
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw
  
  The master oscillator and phase reference system at FLASH must provide several rf reference frequencies to widely spread locations with low phase noise and small long term phase drifts. The phase noise requirements of the 1300 MHz reference is of the order of 0.1 deg. while short and medium term phase stability is of of the order of 0.1 deg. and 1 deg. respectively. The frequency distribution system employs a temperature stabilized coaxial line for rf power distribution and a fiber optic system for the monitoring of phase drifts. Presented are the the concept, design and performance measured in the accelerator environment.  
WEPMN011 Multichannel Downconverter for the Next Generation RF Field Control for VUV- and X-Ray Free Electron Lasers 2071
 
  • M. Hoffmann, F. Ludwig, H. Schlarb, S. Simrock
    DESY, Hamburg
  
  Funding: We acknowledge financial support by DESY Hamburg and the EUROFEL project.

For pump- and probe experiments at VUV- and X-ray free-electron lasers the stability of the electron beam and timing reference must be guaranteed in phase for the injector and bunch compression section within a resolution of 0.01 degree (rms) and in amplitude within 1 10-4 (rms). The performance of the field detection and regulation of the acceleration RF critically influences the phase and amplitude stability. For the RF field control, a multichannel RF downconverter is used to detect the field vectors and control the vectorsum of 32 cavities. In this paper a new design of an 8 channel downconverter is presented. The downconverter frontend consists of a passive rf double balanced mixer input stage, intermediate filters and an integrated 16bit analog-to-digital converter (ADC). The design includes a digital motherboard for data preprocessing and communication with the controller. In addition we characterize the downconverter performance in amplitude and phase jitter, temperature drifts and channel crosstalk in laboratory environment as well as for accelerator operation.