Production of high brightness γ rays through backscattering of laser photons on high-energy electrons

Abstract

Based on the requirements from a conceptual design of a polarized positron beam for future linear colliders, we constructed a special collision system with a short focal length of 150 mm of the laser beams so as to produce γ rays through inverse Compton scattering. In order to achieve efficient laser-electron collisions, we created a special optics to produce very small e --beam sizes of σ ex0 = 7.6 μm and σ ey0 = 5.4 μm in the horizontal and vertical directions at the collision point. Using laser light with a wavelength of 532 nm and an e - beam of 1.28 GeV provided from the ATF-damping ring at KEK, we generated 2 × 10 5 γ rays with a time duration of 26 ps in rms, leading to a peak brightness of 1.7 × 10 18/(mrad 2mm 20.1%bandwidth s) near to the maximum energy of 56 MeV. © 2003 The American Physical Society.