Determination of Circular Polarization of gamma-quanta with Energy > 10 MeV using Compton Polarimeter

The circularly polarized gamma-quanta with energy > 10 MeV are formed during Compton backscattering of circularly polarized laser photons on an electron beam with energy 1.26 GeV. The contribution of nonlinear processes for planned parameters of a laser flash[T. Okugi, Y. Kurihara and M. Chiba, Jpn. J. Appl. Phys. 35, p. 3677 (1996).] can be rather significant, that leads to deterioration of polarization of a resulting gamma-beam. The direct method of measurement of gamma-beam circular polarization will allow not only to estimate a correctness of the theoretical calculations, but also to use the obtained information for simulation of polarization parameters of positrons.