Positron impact ionization of atomic hydrogen

Abstract

Ionization cross sections for positrons impacting on atomic hydrogen have been measured for kinetic energies in the range 15-700 eV. This has been done in a crossed-beam geometry where a magnetically guided positron beam intersects a hydrogen gas jet emanating from a radio frequency discharge tube. Electron impact ionization cross sections were also measured with the same apparatus thus facilitating comparison with, and normalization to, published results. The positron-atomic hydrogen results are found to be significantly lower than those obtained by Spicher et al. (1990).