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Holldack, K.

Paper Title Page
RPAE032 Femtosecond Laser-Electron Interaction in a Storage Ring Studied by Terahertz Radiation 2239
 
  • K. Holldack, S. Khan, T. Quast
    BESSY GmbH, Berlin
  • R. Mitzner
    Universität Muenster, Physikalisches Institut, Muenster
  
  Funding: This work was supported by the german Bundesministerium für Bildung und Forschung (BMBF).

The laser-induced energy modulation of relativistic electrons in the BESSY II storage ring was studied by temporal and spectral characterization of femtosecond far infrared (THz) pulses being emitted due to the fact that dispersive elements convert the energy modulation into a longitudinal density modulation. Bunch shapes down to 3 ps and phase noise effects as well as the length of the femtosecond density modulation and its temporal decay were measured. The THz diagnostics is crucial for the operation of the recently commissioned undulator based "femtosecond slicing" source at BESSY.

 
RPAE033 Commissioning Results from the BESSY II Femtoslicing Source 2309
 
  • S. Khan, K. Holldack, T. Kachel, T. Quast
    BESSY GmbH, Berlin
  • R. Mitzner
    Universität Muenster, Physikalisches Institut, Muenster
  
  Funding: Funded by the Bundesministerium für Bildung und Forschung and by the Land Berlin.

At the BESSY II storage ring, a source of sub-100 fs x-ray pulses with tunable polarization and excellent signal-to-background ratio has been constructed in 2004. This source is based on laser-induced energy modulation ("femtoslicing") and subsequent angular separation of the short-pulse x-rays emitted by an elliptical undulator. The paper reviews the layout of the source and reports on new insights and experimental results obtained while commissioning the source for user operation.

 
RPAE035 Orbit Stability at BESSY 2366
 
  • R. Müller, J. Feikes, K. Holldack, P. Kuske
    BESSY GmbH, Berlin
  
  Funding: Funded by the Bundesministerium für Bildung und Forschung and by the Land Berlin.

Traditionally intrinsic component stability as well as perturbation source identification and suppression (like set-up modifications or feed-forward compensations) have been the preferred methods used to guarantee beam orbit stability for user operation at BESSY. Second focus of activity is the reliability of slow drift control and the high degree of beam position reproducibility maintained under frequently changed operation conditions. Along these lines an overview of the measures taken, the available diagnostic means as well as the achievements and shortcomings of the existing slow orbit feedback is given. Diagnostic capabilities of a fast BPM read-out and data distribution system give insight into the demands on a fast orbit feedback that could provide better operation flexibility and improved performance.