The Baseline Positron Production and Capture Scheme for CLIC

The CLIC study considers the hybrid source using channeling as the baseline for unpolarised positron production. The hybrid source uses a few GeV electron beam impinging on a tungsten crystal target. With the crystal oriented on its < 111 > axis it results an intense relatively low energy photon beam. The later is then impinging on an amorphous tungsten target producing positrons by e+e− pair creation. Downstream the amorphous target, a capture section based on an adiabatic matching device followed by a 2 GHz Pre- Injector Linac focuses and accelerates the positron beam up to around 200 MeV