• D. Schulte, A. Andersson, S. Bettoni, R. Corsini, A. Dubrovskiy, A. Gerbershagen, J.B. Jeanneret, G. Morpurgo, G. Sterbini, F. Stulle, R. Tomás
  CERN, Geneva
• A. Aksoy
  Ankara University, Faculty of Engineering, Tandogan, Ankara
• V.R. Arsov, M.M. Dehler
  PSI, Villigen
• P. Burrows, C. Perry
  JAI, Oxford
• F. Marcellini
  INFN/LNF, Frascati (Roma)

In CLIC very tight tolerances exist for the phase and amplitude stability of the main and drive beam. In this paper we present the status of the CLIC beam phase and amplitude stabilisation concept. We specify the resulting tolerances for the beam and technical equipment and compare to first measurements.

• M.M. Dehler
  PSI, Villigen
• A.E. Candel, L. Lee
  SLAC, Menlo Park, California

Currently an X-band traveling wave accelerator structure is fabricated in a collaboration between CERN, PSI and Sincrotrone Trieste (ST). PSI and ST will use it in their respective FEL projects, CERN will test break down limits and rates for high gradients. A special feature of this structure are two integrated wake field monitors monitoring the beam to structure alignment. The design used an uncoupled model for the fundamental mode, assuming the overall behavior to be the superposition of the individual components. For the wake field monitors, an equivalent circuit was used. This approach has been proven to produce valid structure designs. None the less it cannot approach the quality of a numerical electromagnetic simulation of the full structure, which is ideal for a validation capturing the differences between design models and the real cavity as e.g. internal reflections inside the structure or higher order dispersive terms altering the response of the wake field monitor. Using SLAC's family of massive parallel codes ACE-3P, first results are presented for the fundamental mode and the first transverse mode. They are compared with earlier simulations using simplified models.