Electron Collisions with Metastable Helium

Abstract

Measurements and theoretical studies of electron scattering from the metastable 21,3S excited states of helium are briefly reviewed. An apparatus developed for the study of low energy differential scattering from metastable excited states is discussed in detail and the first results of angular distributions for electrons superelastically scattered from the 21,3S states at incident energies of 5, 10 and 30 eV are presented.