Influence of inelastic collisions on fast electron beam energy relaxation in gas
- 1 — Saint-Petersburg State University
- 2 — Saint-Petersburg Mining University
This work is dedicated to the formulation of an analytical theory for calculating the spacial distribution of energy release in a fast electron beam moving in gas and, particularly, in air, considering inelastic interaction. Electron energies of 1-100 keV are considered. Based on the analysis of data on the cross sections for inelastic and elastic interaction of electrons with gas molecules contained in air, it is concluded that inelastic collisions mainly cause energy relaxation, and elastic collisions cause mostly impulse relaxation. Solving Boltzmann’s kinetic equation for the electrons, it is used a model cross-section for the inelastic collisions of electrons with molecules, which guarantees a good description of the measured energy dependence of the mass stopping power of the electrons. Obtained results for de dependence of electrons´ mean energy on the number of inelastic collisions are in good compliance with the results obtained with the method of expanding distribution function in collision numbers and also with the results of Monte-Carlo simulation.