Keyword: timing
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MOPO121 Large-Scale Optical Synchronization System of the European XFEL laser, FEL, experiment, electron 253
 
  • J.M. Müller, M. Felber, T. Kozak, T. Lamb, H. Schlarb, S. Schulz, C. Sydlo, M. Titberidze, F. Zummack
    DESY, Hamburg, Germany
 
  At the European XFEL, a facility-wide optical synchronization system providing a femtosecond-stable timing reference at more than 40 end-stations had been developed and installed. The system is based on an ultra-stable, low-noise laser oscillator, whose signals are distributed via actively length-stabilized optical fibers to the different locations across the accelerator and experimental areas. There, it is used to locally re-synchronize radio frequency signals, to precisely measure the arrival time of the electron beam for fast beam-based feedbacks, and to phase-lock optical laser systems for electron bunch generation, beam diagnostics and user pump-probe experiments with femtosecond temporal resolution. In this paper, we present the system’s architecture and discuss design choices to realize an extensible, large-scale synchronization infrastructure for accelerators that meets reliability, maintainability as well as the performance requirements. Furthermore, the latest performance result of an all-optically synchronized laser oscillator is shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO121  
About • paper received ※ 12 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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TUPO088 Measurement of Diagnostics Response by RF Parameters for Hard X-ray Line in PAL-XFEL* FEL, diagnostics, gun, linac 531
 
  • H. Yang
    PAL, Pohang, Kyungbuk, Republic of Korea
 
  Funding: *This work is supported by MSIP, Korea.
PAL-XFEL is a hard x-ray (HX) and soft x-ray (SX) FEL machine to generate 2.5 - 15 keV FEL in the HX line and 0.28 - 1.2 keV FEL in the SX line. The HX line consists of an e-gun, a laser heater, S-band accelerators, an X-band linearizer, three bunch compressors (BC), and a dog-leg line. PAL-XFEL maintains the stable operation and FEL delivery with more than 98% availability due to machine stabilities including RF modules. In order to investigate the stable operation, we measure the diagnostics response for bunch charge monitors, energy beam position monitors, bunch length monitors, and a FEL intensity with a photon beam position monitor by RF parameters - RF amplitude and phase for an e-gun, accelerators, and a linearizer. In this paper, we present mainly corresponding RF parameters for e-beam and FEL jitters by this measurement and matrix analysis.
 
poster icon Poster TUPO088 [0.281 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO088  
About • paper received ※ 11 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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TH1A05 Jitter Study for the APS Linac Photo-injector Beam laser, linac, simulation, experiment 647
 
  • D. Hui, M. Borland, J.M. Byrd, Y. Sun
    ANL, Argonne, Illinois, USA
 
  Funding: *Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The APS Linac photo-injector can deliver high brightness electron beams to the Linac Extension Area (LEA) for beam experiments such as TESSA (Tapering Enhanced Stimulated Superradiant Amplification). Beam jitter in the device-under-test (DUT) area of the LEA can adversely affect the quality of data for such experiments. In this paper, a start-to-end simulation of jitter is studied. Sources of jitter include photo-cathode drive-laser arrival time, laser energy, and RF phases and voltages of the photo-cathode gun and accelerating cavities. It is found that at the DUT the relative mean energy jitter is the most significant concern, and that improvements in the Linac RF voltage stability can help to reduce it. RMS energy spread are more sensitive to the laser timing and charge jitter. The laser timing jitter itself can be compressed by the magnetic chicane by a factor of 5.6.
 
slides icon Slides TH1A05 [4.377 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH1A05  
About • paper received ※ 10 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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