The combination of free flying distance grouping method and midpoint method for high accuracy and high efficiency in Monte Carlo simulations of electron-solid interactions

Abstract

Recently, a method to accelerate computational efficiency by orders of magnitude for Monte Carlo simulations of electron-solid interactions has been proposed as the computation engine for the open-source code AMCSET. The method combines consecutive free-flying distances into groups for scattering simulations, assuming equal energy within each group. However, questions regarding accuracy have arisen. If the electron energy at the start of the group is used for the entire group, it can lead to noticeable errors. The error can be avoided by applying the midpoint method, where the average of the starting and ending electron energies within a group is used for scattering calculations. While this energy midpoint selection seems like an obvious choice, this study reports a computational method to predict the energy midpoint of the next group by using the energy loss from the current group, provided the group size is sufficiently large. Thus, the midpoint is calculated explicitly.