• V.G. Khachatryan, V. Sahakyan, A. Tarloyan, V.M. Tsakanov
  CANDLE, Yerevan
• T. Garvey, S. Reiche
  PSI, Villigen

The study of radiation saturation length and saturation power sensitivity to beam main parameters (emittance, energy spread and peak current) at the entrance of the undulator section of PSI-XFEL project is presented. The comparative analysis of the SASE FEL performance with external and natural focusing in undulator section is given.

• K. Manukyan
  YSU, Yerevan
• G.A. Amatuni, A. Sargsyan, V.M. Tsakanov
  CANDLE, Yerevan
• M. Böge, A. Streun
  PSI, Villigen

An online measurement of the beam energy spread is based on the analysis of the decoherence/recoherence signals obtained from the beam position monitors after a single turn beam excitation by a pinger magnet. Furthermore the analysis allows calibration of the model in terms of higher order chromaticities and amplitude dependant tune shifts. An analytical model including 1st and 2nd order chromaticities and amplitude dependant tune shift will be presented.

• M. Ivanyan, V.M. Tsakanov, A. Vardanyan
  CANDLE, Yerevan
• M.M. Dehler, T. Schmidt, A. Streun
  PSI, Villigen

The longitudinal and transverse impedances of CPMU (cryogenic permanent magnet undulators) of the SLS storage ring are evaluated. The study takes into account the walls frequency dependent conductivity and the electrical and magnetic properties of the material at low temperature.

• M. Ivanyan, V.M. Tsakanov
  CANDLE, Yerevan
• M.M. Dehler
  PSI, Villigen
• A. Grigoryan
  YSU, Yerevan

The resistive longitudinal and transverse wakefields, longitudinal loss and transverse kick factors excited by the electron bunch in undulator section of the PSI-XFEL are given. The ordinary and in vacuum undulators are considered. For in vacuum undulator the modified technique for impedance calculation is developed.