Design of a Polarised Positron Source Based on Laser Compton Scattering
  We describe a scheme for producing polarised positrons at the ILC from polarised X-rays created by Compton scattering of a few-GeV electron beam off a CO2 or YAG laser. This scheme is very energy effective using high finesse laser cavities in conjunction with an electron storage ring. 
S. Araki, Y. Higashi, Y. Honda, Y. Kurihara, M. Kuriki, T. Okugi, T.   Omori, T. Taniguchi, N. Terunuma, J. Urakawa, X.Artru...