Slow Electrons from Electron-Impact Ionization of He, Ne, and Ar

Abstract

A trapped-electron technique is used to determine the integral cross sections for production of secondary electrons in the energy range from 0 to 1 eV resulting from electron-impact ionization of He, Ne, and Ar. For incident electron energies above 150 eV the slow-electron production cross section decreases approximately as the total-ionization cross section. A simple Born calculation for the case of atomic hydrogen also shows this general behavior. The measured absolute cross sections compare well with recently measured relative angular distributions and with Born and Born-exchange calculations.