Polarized triplet production by circularly polarized photons

A process of pair production by a circularly polarized photon in the field of an unpolarized atomic electron was considered in the Weizaecker-Williams approximation. The degree of longitudinal polarization of a positron and an electron was calculated. An exclusive cross section, as well as a spectral distribution, were obtained. We estimate the accuracy of our calculations at the level of a few percent. We show the identity of the positron polarization for the considered process and for the process of pair production in the screened Coulomb field of a nucleus.