SMART Scattering Matrices for Single Collision Electron Monte Carlo Calculations

Abstract

An angular redistribution function for electron scattering based on Goudsmit-Saunderson theory has been implemented in a Monte Carlo electron transport code in the form of a scattering matrix that the authors term SMART (simulating many accumulative Rutherford trajectories). These matrices were originally developed for use with discrete ordinates electron transport codes. An essential characteristic of this scattering theory is a large effective mean-free-path for electrons, much larger in fact than the true single collision mean-free-path. When this theory is applied to single collision analog Monte Carlo calculations, excellent results are obtained for the principal quantities of interest, transmission and reflection spectra, and energy deposition. A derivation of the SMART scattering matrix is presented, using the method of weighted residuals to obtain the discretized form of the Spencer-Lewis equation for electron transport. Results of Monte Carlo calculations for electron transport in aluminum slabs for both beam source and isotropic source configurations are given. These results are compared with similar benchmark calculations made with the TIGER code series.