A Monte Carlo model of alkali halides under low energy electron irradiation

A Monte Carlo random walk model was used to study the creation and dynamics of F- and H-centers induced by electron irradiation in alkali-halide singl e crystals. The purpose of the study was to observe the effects of depth de pendent electron energy deposition near the surface region using beam energ ies of 500 eV or less and relatively low currents (< 100 mu A/cm(2)). The c alculations were carried out using the parameters appropriate for an FCC Li F single crystal at room temperature. Depth dependent dynamics of F- and H- centers are also presented as well as F-H center recombination rates, and t hermal and non-thermal halogen production rates at the surface. The model d emonstrates that F-H center recombination dramatically affects the F-center distribution. F-center distributions are found to be peaked at the surface and do not reflect the initial energy deposition profile.