Theoretical derivation and benchmarking of cross sections for low-energy electron transport in gold

Abstract

Simulation of transport of electrons through matter is used in many applications. Some of them need models that are both efficient in terms of computing time and accurate over a wide range of electron energy. For certain applications such as radiochemistry and radiotherapy enhanced by metallic nanoparticles, it is desirable to consider relatively low-energy electrons. We have implemented a physical model for electron transport down to low energy in solid metallic media that meets both of the aforementioned requirements. The main goal of this paper is to present the theoretical framework of our Monte Carlo simulation, its application to gold metal and an extensive comparison with available data for gold foils irradiated by electron beams, for projectile energies ranging from a few eV to 90 keV. In particular, we calculated secondary electron emission to assess the accuracy of our code at energies below 50 eV. A close agreement with experiment is obtained for a large range of energy, even though the backward emission yields of low-energy electron are systematically underestimated. Nevertheless, the quality and numerical efficiency of the simulation are encouraging for nanoscale applications such as nanodosimetry or radiochemistry in presence of gold nanoparticles.