Intense gamma-ray source for polarized positron beam generation

Abstract

In order to generate a polarized positron beam for a linear collider, an intense circularly polarized gamma-ray generation is considered by passing a circularly polarized CO2 laser beam through an optical lens series with periodic focal points, where a 5.8 GeV bunched electron beam is collided. It is shown by diffraction analysis that laser beam loss in the lens series is very small, and the beam size is reduced to 26 micrometers The electron beam size is reduced to 34 micrometers in a superconducting solenoid with a field of 15 T. The laser power required for the gamma-ray yield of 7 x 10(exp 15) gamma/s for JLC is 24 kW. A single pass FEL amplification using the same electron beam at 560 MeV can produce 9.5 kW, which is not far away from the required power.