Electron impact ionization of argon: measurements of triple differential cross sections

Abstract

For primary energies E0=100 eV and 250 eV the ionization process of argon due to electron impact has been studied in detail. In a coincidence experiment, both ionization electrons have been analysed with respect to their energy and scattering angles. For a fixed scattering angle of the fast electron the angular dependence of the slow electron has been determined in the plane given by the momentum of the incoming and scattered electrons. This has been done for various sets of energies of the two outgoing electrons. There are again two groups of slow electrons as appeared in earlier measurements on helium. The angular positions of the binary encounter peak and the recoil peak show similar dependence on the scattering parameters as found for helium. In addition these peaks show some structure probably due to the fact that a p-electron has been ejected in the collision process.