• 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.

• F. Peauger, W. Farabolini, P. Girardot
  CEA, Gif-sur-Yvette
• A. Andersson, G. Riddone, A. Samoshkin, A. Solodko
  CERN, Geneva
• R.J.M.Y. Ruber
  Uppsala University, Uppsala
• R. Zennaro
  PSI, Villigen

To achieve high luminosity in CLIC, the accelerating structures must be aligned to an RMS accuracy of 5 μm with respect to the beam trajectory. Position detectors called Wakefield Monitors (WFM) are integrated to the structure for a beam based alignment. This paper describes the requirements of such monitors. The development plan and basic feature of the WFM as well as the accelerating structure working at 12 GHz and 100 MV/m are shortly described. Then we focus on detailed electromagnetic simulations and design of the WFM itself. In particular, time domain computations are performed and an evaluation of the intrinsic resolution is done for two higher order modes at 17 and 24 GHz. The mechanical design of the accelerating structure with WFM is also presented. Precise machining with a tolerance of 2.5 μm and a surface roughness of 0.025 μm is demonstrated. The fabrication status of three complete accelerating structures with WFM is finally presented for a feasibility demonstration with beam in CTF3 at CERN.