Author: Urakawa, J.
Paper Title Page
MOP064 Asymmetric Laser Radiant Cooling in Storage Rings 229
 
  • E.V. Bulyak
    NSC/KIPT, Kharkov, Ukraine
  • J. Urakawa
    KEK, Ibaraki, Japan
  • F. Zimmermann
    CERN, Geneva, Switzerland
 
  Laser pulses with small spatial and temporal dimensions can interact with a fraction of the electron bunches circulating in Compton storage rings. We studied synchrotron dynamics of such bunches when laser photons scatter off from the electrons with energy higher than the synchronous energy. In this case of ‘asymmetric cooling', as shown theoretically, the stationary energy spread is much smaller than under conditions of regular scattering; the oscillations are damped faster. Coherent oscillations of large amplitude may be damped in one synchrotron period, which makes this method feasible for injection the bunches into a ring in the longitudinal phase space. The theoretical results are validated with simulations.  
 
FROAN4 Femtosecond RF Gun Based MeV Electron Diffraction 2558
 
  • J. Yang, K. Kan, Y. Murooka, N. Naruse, K. Tanimura, Y. Yoshida
    ISIR, Osaka, Japan
  • J. Urakawa
    KEK, Ibaraki, Japan
 
  Ultrafast time-resolved electron diffraction based on a photocathode rf electron gun is being developed in Osaka University to reveal the hidden dynamics of intricate molecular and atomic processes in materials. A new structure rf gun has been developed to generates a low-emittance femtosecond-bunch electron beam, and has been used successfully for the single-shot MeV electron diffraction measurement. The transverse emittance, bunch length and energy spread were measured. The growths of the emittance, bunch length and energy spread due to the rf and the space charge effects in the rf gun were investigated by changing the laser injection phase, the laser pulse width and the bunch charge. The same demonstrations of the electron diffraction measurement were reported.  
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