| Paper |
Title |
Page |
| TUPCH188 |
Phase Stability of the Next Generation RF Field Control for VUV- and X-ray Free Electron Laser
|
1453 |
| |
- F. Ludwig, M. Hoffmann, H. Schlarb, S. Simrock
DESY, Hamburg
|
|
| |
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 directly influences the phase and amplitude stability. In this paper we present the phase noise budget for a RF-regulation system including the noise characterization of all subcomponents, in detail down-converter, ADC sampling, vector-modulator, master oscillator and klystron. We study the amplitude to phase noise conversion for a detuned cavity. In addition we investigate the beam jitter induced by these noise sources within the regulation and determine the optimal controller gain. We acknowledge financial support by DESY Hamburg and the EUROFEL project.
|
|
| TUPCH191 |
Considerations for the Choice of the Intermediate Frequency and Sampling Rate for Digital RF Control
|
1462 |
| |
- S. Simrock, M. Hoffmann, F. Ludwig
DESY, Hamburg
- M.K. Grecki, T. Jezynski
TUL-DMCS, Lodz
|
|
| |
Modern FPGA-based rf control systems employ digital field detectors where an intermediate frequency (IF) in the range of 10 to more than 100 MHz is sampled with a synchronized clock. Present ADC technology with 14-16 bit resolution allows for maximum sampling rates up to 250 MHz. While higher IF's increase the sensitivity to clock jitter, lower IF frequencies are more susceptible to electromagnetic noise. The choice of intermediate frequency and sampling rate should minimize the overall detector noise, provide high measurement bandwidth and low latency in field detection, and support algorithms for optimal field estimation.
|
|