Low-energy electron transport in non-uniform media

Abstract

We simulated the transport of low and medium energy electrons with energies between 1.26eV and 10keV in non-uniform carbon targets using the track structure Monte Carlo code TRAX which has several applications in biophysics and radiation physics. Cross sections for electrons incident on carbon have been critically assessed. Furthermore the code has been extended to handle non-uniform targets allowing a complex geometry description. Solid state targets, which are commonly used as targets in electron spectrometers and other devices can be non-uniform, e.g. have highly irregular surfaces or pinholes. The resulting electron spectra can be significantly affected by these non-uniformities. We reproduce experimental data obtained by GSI’s Toroid electron spectrometer using thin solid state foils as targets. This unique experiment was designed to gain further insight in the emission and transport of low energy electrons in solids to improve the description of microscopic energy deposition. The realistic implementation of non-uniform targets in TRAX was verified by comparison with available experimental data. The increased backscattering due to the roughness of an unpolished target in comparison with polished ones could be reproduced as well as secondary electron spectra from the Toroid.