Experimental demonstration of feasibility of a polarized gamma-source for ilc based on compton backscattering inside a co2 laser cavity

Compton interaction point incorporated into a laser cavity is the key element of the polarized positron source (PPS) concept proposed for ILC in [1]. According to this proposal, circularly polarized gamma rays are produced via Compton backscattering from a linac´s electron beam (e macr-beam) inside a CO₂ laser amplifier cavity. Intra-cavity positioning of the interaction point (IP) allows laser energy recycling to match the electron beam format. We conducted experimental tests of multi-pulse operation of such active Compton cavity upon injection of a picosecond CO₂ laser beam. Together with earlier demonstration of a high x-ray yield via the emacr-beam/CCv laser backscattering, these new results show a viability of the entire PPS concept and closely prototype the laser source requirements for ILC.