Meastri: A hybrid analytical/monte carlo code for particle transport in solids

Abstract

We report on a hybrid analytic/Monte Carlo code for evaluating particle transport in solids. In this code, atomic concentrations in the near surface implanted region of a target material, { N k ( x, t)}, are propogated in time through the method of equivalent atomic stopping (MEAS). The implantation source profiles { P k ( x, t)}, initially obtained from the TRIM code, are propagated along with the { N k ( x, t)}. In addition, TRIM is invoked periodically to provide updated profiles { P k ( x, t)}, since the MEAS procedure includes only first order corrections to the { P k }. The code provides for simultaneous implantation of different atomic species and includes the local mixing model (LMM) for describing buildup to saturation and isotope exchange for implantation of hydrogen and/or other species. Since the MEAS procedure is analytic, both sputtering and diffusion are included in a natural way, and disparate time scales, e.g. for implantation, sputtering and diffusion, are easily accommodated. The code is particularly useful for high fluence implantation. Example calculations for simultaneous C and D implantation into graphite are compared with experimental data obtained from TFTR limiter tiles.