Electron capture into continuum states of fast channelled protons

Abstract

The yield of electrons captured into continuum states of 200-300 keV protons is measured for conditions of both (111) channelling and random impact on single-crystal gold foils. The measured yields under channelling conditions are approximately 80% of those under random impact. To discuss this theoretically it is shown that the channelled protons capture only from the 5d electrons whereas the random beam captures from 5d, 5p and 5s. Using atomic Hartree-Fock wavefunctions throughout reasonable agreement with experiment is obtained, particularly under channelling conditions.