Validation Test of Geant4 Simulation of Electron Backscattering

TL;DR

This study thoroughly evaluates Geant4's ability to simulate electron backscattering across a wide energy range and various models, revealing significant evolution over versions and identifying the most accurate configurations compared to experimental data.

Contribution

It provides a comprehensive validation of Geant4 electron backscattering models from versions 9.1 to 10.1 using statistical analysis, highlighting model performance and evolution.

Findings

Geant4 versions show varied accuracy in backscattering simulation.

Urban model in Geant4 9.1 and Coulomb scattering in 10.0 best match experiments.

Single scattering models perform better at low energies down to a few keV.

Abstract

Backscattering is a sensitive probe of the accuracy of electron scattering algorithms implemented in Monte Carlo codes. The capability of the Geant4 toolkit to describe realistically the fraction of electrons backscattered from a target volume is extensively and quantitatively evaluated in comparison with experimental data retrieved from the literature. The validation test covers the energy range between approximately 100 eV and 20 MeV, and concerns a wide set of target elements. Multiple and single electron scattering models implemented in Geant4, as well as preassembled selections of physics models distributed within Geant4, are analyzed with statistical methods. The evaluations concern Geant4 versions from 9.1 to 10.1. Significant evolutions are observed over the range of Geant4 versions, not always in the direction of better compatibility with experiment. Goodness-of-fit tests complemented by categorical analysis tests identify a configuration based on Geant4 Urban multiple scattering model in Geant4 version 9.1 and a configuration based on single Coulomb scattering in Geant4 10.0 as the physics options best reproducing experimental data above a few tens of keV. At lower energies only single scattering demonstrates some capability to reproduce data down to a few keV. Recommended preassembled physics configurations appear incapable of describing electron backscattering compatible with experiment. With the support of statistical methods, a correlation is established between the validation of Geant4-based simulation of backscattering and of energy deposition.