Transmission and backscattering energy distributions of slow electrons from metallic targets

Abstract

Transmission probabilities of slow electrons normally incident on aluminum and copper thin film targets are stochastically modeled within a Monte-Carlo framework in the examined energy range 0.5-4 keV. Attention has also been given to transmission and backscattering energy distributions. The agreement between theory and experiment is found to be good in all cases.

Simulation of positron backscattering on Al, Cu, Ag and Au targets using GEANT4 code

“…Where, Bsc(t) is referred to a given thickness of targets and Bsc(si) is referred to the semi‐infinite targets. The results show that for a certain material, the positron backscattering coefficient increases gradually until the target thickness increases to a critical value (which depends on the target material) and then becomes almost constant . This could be explained by the simple fact that if the target is a bulk material, then the number of transmitted positrons would be zero and the fraction of backscattered positrons could reach its maximum value (backscattering coefficients of semi‐infinite targets).…”

“…The results show that for a certain material, the positron backscattering coefficient increases gradually until the target thickness increases to a critical value (which depends on the target material) and then becomes almost constant. [15,21,37,38] This could be explained by the simple fact that if the target is a bulk material, then the number of transmitted positrons would be zero and the fraction of backscattered positrons could reach its maximum value (backscattering coefficients of semi-infinite targets). It could be noticed that the critical thickness decreases with the increase of atomic number Z, which indicates that the impact of target surface on the backscattering coefficient is also related to the atomic number Z.…”

Positron backscattering from an Al target: analytical calculation and Monte Carlo simulation

“…The backscattering coefficient, which may provide stringent tests on the accuracy of the description of the scattering processes, has been obtained using both the Vicanek and Urbassek theory 15 and Monte Carlo simulation. The Monte Carlo code used here has the same general structure as that used in our previous publications 16,17 but with the incorporation of a new approximation for the differential elastic scattering cross section. …”

Positron and electron backscattering from elemental solids in the 1–10 keV energy range

“…Calculations of electron and positron backscattering coefficients as a function of both incident angles and target atomic number Z for a large range of energies have been made by several authors [6, 14, 20, 21, 23, 27-29, 31, 32, 34, 35]. More general theoretical problems of calculating transmission, backscattering and absorption of electrons impinging on supported and unsupported thin films have been also reported [30,[36][37][38]. However, relatively few data exist for low energy electrons and positrons.…”