Keyword: free-electron-laser
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MOPO039 Status Update of the Fast Energy Corrector Cavity at FLASH cavity, electron, laser, coupling 112
 
  • S. Pfeiffer, J. Branlard, L. Butkowski, M. Hierholzer, M. Hoffmann, K. Honkavaara, H. Schlarb, Ch. Schmidt, S. Schreiber, M. Vogt, J. Zemella
    DESY, Hamburg, Germany
  • M. Fakhari
    CFEL, Hamburg, Germany
 
  Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453.
Linear accelerator facilities driving a free-electron laser require femtosecond precision synchronization between external laser systems and the electron beam. Such high precision is required for pump-probe experiments and also for example for the electron bunch injection into a plasma bubble for laser plasma acceleration. An upgrade of the fast intra-train beam-based feedback system is planned at the Free-Electron Laser FLASH in Hamburg, Germany. This linear accelerator is based on superconducting (SRF) technology operating with pulse trains of maximum 1 MHz bunch repetition rate. Arrival time fluctuations of the electron beam are correctable by introducing small energy modulations prior to the magnetic bunch compressor. This contribution focuses on the design and the characterization of a normal-conducting RF (NRF) cavity with large bandwidth, mandatory to correct fast arrival time fluctuations. The cavity has recently been installed in the FLASH beamline. First measurements with the new cavity will be presented.
 
poster icon Poster MOPO039 [1.884 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO039  
About • paper received ※ 13 September 2018      issue date ※ 18 January 2019  
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MOPO042 Evolutionary Many-objective Optimization Algorithm for Large-bandwidth Free-Electron-Laser Generation electron, FEL, laser, linac 121
 
  • J.W. Yan, H.X. Deng
    SINAP, Shanghai, People’s Republic of China
 
  Funding: National Natural Science Foundation of China , the National Key Research and Development Program of China, the Young Elite Scientist Sponsorship Program by CAST and Ten Thousand Talent Program.
X-ray free-electron lasers (XFELs) are leading-edge instruments in a wide range of research fields. Besides pursuing narrow bandwidth FEL pulses, the large-bandwidth XFEL pulses are very useful in various spectroscopy experiments, multi-wavelength anomalous diffraction, and X-ray crystallography. Overcompression operation scheme can be utilized to generate electron beams with large energy chirp which is benefit for bandwidth broadening. Recently, an evolutionary many-objective (having four or more objectives) algorithm, NSGA-III, was used to optimize the electron beam parameters in the overcompression including energy chirp, energy spread, current profile, peak current, and projected emittance. In this paper, combining with the Xie’s semianalytical estimate formula, the NSGA-III is utilized to find an optimal working point of linac by optimizing the XFEL pulse properties directly. Start-to-end numerical simulations based on the Shanghai soft X-ray Free-Electron Laser user facility parameters demonstrate that a full bandwidth of 4.75% can be generated.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO042  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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