Low energy (e,2e) studies of the noble gases in the perpendicular plane

Detailed (e,2e) studies of the electron-impact ionization of the noble gases, helium, neon, argon, krypton and xenon, have been carried out from near threshold to intermediate energies, where the outgoing electrons carry equal energy from the interaction. The experiments were conducted in the perpendicular plane, where the outgoing electrons are both detected orthogonal to the incident electron beam. For electrons to emerge in this geometry they must undergo multiple scattering, including scattering from the nucleus of the target, and so this geometry provides a highly sensitive test of the most sophisticated scattering theories. The data show that the cross sections undergo complex variations as a function of incident energy, and in particular ionization of the heaviest target is at variance to all others that have been studied here. © 2010 IOP Publishing Ltd.