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acceleration

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MOPP036 Next Generation Synchronization System for the VUV-FEL at DESY laser, electron, cavity, fel 118
 
  • H. Schlarb, V. Ayvazyan, F. Ludwig, D. Noelle, B. Schmidt, S. Simrock
    DESY, Hamburg
  • F.X. Kaertner
    MIT, Cambridge, Massachusetts
  • A. Winter
    Uni HH, Hamburg
  
 

The control and stabilization of the longitudinal beam profile and the bunch arrival time in linac driven VUV or X-ray Free-Electron Lasers require special effort and new developments in the fields of low level RF controls, global synchronization systems and longitudinal beam feedbacks. In this paper we describe the required upgrades for the VUV-FEL at DESY to synchronize the FEL pulse and optical lasers to the level of hundred femtoseconds (FWHM).

   
    
TUOB004 Bunch Compression Stability Dependence on RF Parameters linac, emittance, bunch-compressor, simulation 250
 
  • T. Limberg, M. Dohlus
    DESY, Hamburg
  
 

In present designs for FEL's with high electron peak currents and short bunch lengths, higher harmonic RF systems are often used to optimize the final longitudinal charge distributions. This opens degrees of freedom for the choice of RF phases and amplitudes to achieve the necessary peak current with a reasonable longitudinal bunch shape. It had been found empirically that different working points result in different tolerances for phases and amplitudes. We give an analytical expression for the sensitivity of the compression factor on phase and amplitude jitter for a bunch compression scheme involving two RF systems and two magnetic chicanes as well numerical results for the case of the European XFEL.

   
    
THPP035 Observation of Femtosecond Bunch Length Using a Transverse Deflecting Structure bunch-compressor, linac, sase, energy-spread 538
 
  • M. Huening, A. Bolzmann, H. Schlarb
    DESY, Hamburg
  • J.C. Frisch, D.J. McCormick, M.C. Ross, T.J. Smith
    SLAC, Menlo Park, California
  • J. Rossbach
    Uni HH, Hamburg
  
 

The design of the VUV-FEL at DESY demands bunch lengths in the order of 50 fs and below.For the diagnostic of such very short bunches a transverse deflecting RF structure (LOLA) has been installed which streaks the beam according to the longitudinal distribution. Tests in the VUV-FEL yielded a rich substructure of the bunches. The most pronounced peak in the has a rms length of approximately 50 fs during FEL operation and below 20 fs FWHM at maximum compression. Depending on the transverse focusing a resolution between 10-50 fs was achieved.