Maksim V. Kuzin
UNPOLARIZED POSITRON SOURCES USING CHANNELING FOR FUTURE COLLIDERS
R.Chehab, I.Chaikovska, H.Guler (LAL-Orsay), X.Artru, M.Chevallier (IPNL), P.Sievers, L.Rinolfi(CERN), K.Furukawa, T.Kamitani, F.Miyahara, T.Suwada, M.Satoh, Y.Seimiya, K.Umemori (KEK), P.Martyshkin (BINP)
Investigations on unpolarized positron sources for future colliders have shown the great advantages of using axial channeling radiation for e+e- pair production; both high yields e+/e- and moderate energy deposition are expected. After a short review of this kind of sources with the two options: all-crystal and hybrid, we describe shortly the results of the experiments carried out at CERN and KEK. Applications to future linear (CLIC, ILC) and circular (FCC-ee) colliders are presented. Emphasis is put on the experiment performed at KEK, last year, on a hybrid source with a new converter made of small tungsten spheres; some of the gathered results are presented and discussed. Some perspectives are, then, discussed.