Target dependence of angular distributions for near-threshold (e,2e) processes.

Abstract

Distorted-wave calculations of the triply differential cross sections for electron-impact ionization of H and He targets are presented for final-state electrons sharing 4-eV excess energy and leaving in opposite directions. The experimentally observed target dependence of the angular distributions is shown to stem essentially from short-range effects on the {ital s}-wave phase shifts of both incident and final-state continuum electrons.