Monte Carlo calculation of the total energy loss of electrons from 0.3 to 1 MeV in aluminium foils

Abstract

Since low-energy electrons straggle in the beam extraction window, their total energy loss in this window cannot be given by the product of the theoretical energy loss rate of electrons passing through matter, and the foil thickness. This energy loss is calculated by the Monte Carlo method, including the energy loss by knock-on collisions and the difference between real path length and foil thickness. The total energy loss thus obtained is, for instance, about two times as large as the product of the theoretical energy loss rate based on Bethe's formula and the foil thickness, for an initial energy of 300 keV and a foil, 150 μm thick, made of Al, and decreases gradually with increasing initial energy up to about 1 MeV, while the theoretical energy loss rate is almost constant for electrons having kinetic energy above ≈ 300 keV.