• B. Beutner, S. Reiche
  PSI, Villigen

The SwissFEL facility will produce coherent, ultra-bright, and ultra-short photon pulses covering a wavelength range from 0.1 nm to 7 nm, requiring an emittance between 0.18 to 0.43 mm mrad. It consists of an S-band rf-gun and booster and a C-band main linac, which accelerates the beam up to 5.8 GeV. Two compression chicanes will provide the required peak current of 2.7 kA. An important issue is the stability of the photon pulses leaving the undulator toward the user stations. Arrival time and peak current stability are crucial factors for the scientific return of the user experiments. Machine stability, especially the rf jitter, will directly affect these important figures. Shot-to-shot jitter is of main interest here since long term drifts can be compensated by slow feedback systems. We present a study on stability including rf tolerances for a new optimised layout of the SwissFEL.