COMPUTER SIMULATION OF RADIATION DAMAGE IN POTASSIUM HALIDES BY LOW AND HIGH ENERGY RECOILS

Abstract
Collision cascades induced by recoiling atoms in potassium halides are simulated by the computer program MARLOWE (binary collision approximation) [1-3] in order to evaluate the characteristics of defect zones stemming from recoils by reactor neutron irradiation (some 100 eV to 60 keV primary energy). The defects formed in low energy cascades are accumulated in small zones with high probability of annealing, since most of them are situated within their radius of spontaneous recombination. At energies greater than 10 keV channeling-dechanneling processes occur which lead to a straight track of the primary, bordered by periodic displacements with small energy transfer on the order of 10 eV. These defects have larger separations from each other and, thus, a lower recombination chance than those in low energy cascades. The calculation may explain the reduction of traps for diffusion formed by high energy recoils (n, p-reactions and elastic collisions with fast neutrons) when overlapped by low energy cascades (n, γ-reactions), as reported in the preceding paper. Moreover, the calculation yields interesting information on the generation of tracks by high energy heavy particles in solid state detectors.