Energy and Angular Distributions of Electrons Ejected from Hydrogen and Helium by 100- to 300-keV Protons

Abstract

Measurements have been made of the differential cross sections for ejection of electrons of various energies at various angles from hydrogen and helium gases bombarded by 100- to 300- keV protons. After electrostatic analysis, individual electrons were counted using an electron-multiplier detector. Measurements were made at nine angles from 10° to 160° and at electron energies down to 2 eV. Comparison is made with Born-approximation calculations using hydrogen wave functions but with the results scaled to molecular hydrogen and to helium. The Gryziński classical theory is also used to calculate cross sections and these are compared with the Born approximation and with the experimental values. A simple semi-empirical equation has been found which fits the energy distributions fairly well at low and intermediate energies.