AN ELASTIC CROSS-SECTION MODEL FOR USE WITH MONTE-CARLO SIMULATIONS OF LOW-ENERGY ELECTRON-SCATTERING FROM HIGH ATOMIC-NUMBER TARGETS

The form of the screened Rutherford elastic scattering cross section has been modified to approximate the Mott scattering cross section for low energy electrons interacting with high atomic number targets, both for the total and the differential elastic cross section. A modified form of the total scattering cross section has been found that fits the Mott scattering cross section derived using a partial wave expansion. The fit is from atomic number 6-92 over the energy range 1-100 keV. The differential elastic cross section has been modeled using a screened Rutherford distribution plus an isotropic distribution. The ratio of forward to backscattering found from the Mott cross section was used as a fitting criteria. The screened Rutherford distribution is fitted to the forward scattering half-angle of the Mott distribution and the size of the isotopic distribution is then adjusted to give the correct forward to backscattering ratio. This differential form has been used in a Monte Carlo simulation of the backscattering from Au. Both the total and the differential cross sections are straightforward to implement in a Monte Carlo simulation of electron/target scattering.