AN AB-INITIO MONTE-CARLO STUDY OF LOW-ENERGY POSITRON AND ELECTRON IMPLANTATION IN ELEMENTAL METALS AND MULTILAYERS

A Monte Carlo code developed at Brookhaven to study positron and elect ron implantation in solids will be discussed. This code models the tra jectories of a large number of positrons or electrons as they move thr ough the material and uses this information to calculate stopping prof iles, backscattered fractions and transmitted fractions. The particle- atom interactions are incorporated via elastic and inelastic scatterin g cross-sections. The incident particle energies vary from 1 to 10 keV and the simulation stops when the particle energy goes down to 25 eV or if the particle is backscattered. Main results of our Monte Carlo s imulations of the mean implantation depth and implantation profiles fo r both semi-infinite metallic elements and multilayers will be discuss ed.