Design of a polarized positron source for linear colliders

We propose a design of a polarized positron source for linear colliders. The design is based on electron-positron pair creation from polarized gamma-rays which are produced by Compton scattering of circularly polarized laser light off a high-energy electron beam. Polarized positrons are created from those gamma-rays incident on a thin conversion target. A future linear collider of the TeV-energy region requires an extraordinary large number of positrons (similar to 1 x 10(10) positrons/ bunch) in a multi-bunch time structure. To meet these requirements, our design employs a high-current, low-emittance electron beam of 5.8 GeV, 10 CO2 lasers, and 200 laser-electron collision-points. At each collision point, a pair of specially designed parabolic mirrors is installed to achieve efficient head-on collisions. This system allows us to produce high-intensity polarized gamma-rays, which effectively generate high-intensity polarized positrons with the magnitude of polarization greater than 50%. (C) 2003 Elsevier Science B.V. All rights reserved.