Depolarization of polarized slow positrons in solids

We have investigated spin-precession mechanisms of polarized slow positrons in materials caused by multiple Coulomb scatterings, Bhabha scatterings and bremsstrahlungs. The depolarizations of polarized slow positrons in various materials have been estimated and found that the degree of depolarization is strongly dependent on the atomic number of materials. A Monte-Carlo simulation program, in which the theoretical formulations of spin precession due to the three processes mentioned above are incorporated, have been developed and applied successfully for designing the production system of polarized slow positrons.