Energy spectra and angular distributions of charged particles backscattered from solid targets

Abstract

In this study, the EGSnrc (Electron Gamma Shower) Monte Carlo radiation transport code is used to simulate the energy spectra and the angular distributions of charged particles backscattered from solid targets. The study covers the energy range 10-70 keV, which is of interest to applied physics fields such as scanning electron microscopy, microprobe analysis and x-ray imaging. Simulation results are compared with experimental data from 11 different published experiments (1954-2002). Comparisons include electrons and positrons, low-and high-Z targets, normal and oblique incidence, different backscatter angles and backscatter planes, and backscatter from thin films. EGSnrc simulation results show excellent agreement with the majority of the published experimental data. Possible experimental and computational uncertainties explaining the few noted discrepancies are discussed. This study concludes that EGSnrc produces accurate backscatter data in the kilovoltage energy range. A

Backscattered Electrons Spectra and Angular Distributions: Simulations with EGS5

“…A dq=0.01 step was employed giving histograms of 108 points (3* beyond Emax). The results presented here were obtained with a Xeon with 12 cores, 4x10 6 shots per image, totalizing almost 5x10 7 total shots. The time for such a run was 8 minutes.…”

“…Of particular interest is the work Ali and Rogers [6], who, with the EGSnrc [7] system conducted an analysis on a large number of experiments. The present work makes a similar investigation but differs in two important aspects.…”

Backscattering of MeV Electrons. An Analysis of Tabata’s Experiment with Geant4

“…For example, in medical physics, mainly in the kilovolt range of energies, it is of critical importance in establishing accurate irradiation doses to the patients. The papers of Ali and Rogers [2] and a previous work by the present author [3], are dealing with this range of energy. Other fields of interest are surface science, electron field microscopy and many others.…”

Monte Carlo simulation of Tabata’s electron backscattering experiments

“…The electron backscattering coefficients obtained from experiments and calculations have been compared by several researchers including Seltzer and Berger [2] by using the ETRAN code [3]; Ferrari et al [4] by using the FLUKA code [5]; Baró et al [6], Benedito et al [7], and Sempau et al [8] by using the PENELOPE code [9]; Ali and Rogers [10,11] by using the EGSnrc code [12]; and Ito et al [13] by using the ITS 3.0 code [14], as listed in Table 1. These comparisons were carried out from low to high atomic number materials in the keV energy range; however, only Ito et al carried out at low atomic number materials using Be and C targets in the MeV range.…”