Nonequilibrium charge states of recoil ions in high resolution elastic recoil detection analysis

Abstract

The measured profiles of a high resolution elastic recoil detection (ERD) analysis utilizing electrostatic or magnetic spectrographs may contain artefacts if only one charge state is measured. This effect is demonstrated by the analysis of 31.8 MeV 12C q+ recoil ions of different charge states q + scattered from a pure graphite sample using 60 MeV 58Ni 8+ ions at a scattering angle of 15° and by the analysis of a thin BN film. The primary charge state distribution obtained from scattering events very near the surface significantly deviates from the equilibrium one which is measured for carbon ions scattered deeper than 10 17 at/cm 2 below the surface. Charge exchange cross sections between the main charge states are obtained analysing the depth dependent charge state distributions.