• L. Rinolfi, F. Antoniou, H.-H. Braun, Y. Papaphilippou, D. Schulte, A. Vivoli, F. Zimmermann
  CERN, Geneva
• E.V. Bulyak, P. Gladkikh
  NSC/KIPT, Kharkov
• R. Chehab
  IN2P3 IPNL, Villeurbanne
• J.A. Clarke
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• O. Dadoun, P. Lepercq, R. Roux, A. Variola, Z.F. Zomer
  LAL, Orsay
• W. Gai, W. Liu
  ANL, Argonne
• T. Kamitani, T. Omori, J. Urakawa
  KEK, Ibaraki
• M. Kuriki
  HU/AdSM, Higashi-Hiroshima
• I. Pogorelsky, V. Yakimenko
  BNL, Upton, Long Island, New York
• T. Takahashi
  Hiroshima University, Graduate School of Science, Higashi-Hiroshima

The CLIC polarized positron source is based on a positron production scheme in which polarized photons are produced by Compton process. Compton backscattering happens in a so-called "Compton ring" where an electron beam of 1.06 GeV interacts with a powerful laser beam amplified in an optical resonator. The circularly-polarized gamma rays are sent on to a target, producing pairs of longitudinally polarized electrons and positrons. An Adiabatic Matching Device maximizes the capture of the positrons. A normal-conducting 2 GHz Linac accelerates the beam up to 2.424 GeV before injection into the Pre-Damping Ring (PDR). The nominal CLIC bunch population is 4.4x10⁹ particles per bunch. Since the photon flux coming out from a "Compton ring" is not sufficient to obtain the requested charge, a stacking process is required in the PDR. Another option is to use a "Compton Energy Recovery Linac" where a quasi-continual stacking in the PDR could be achieved. A third option is to use a "Compton Linac" which would not require stacking. We describe the overall scheme as well as advantages and constraints of the three different options.