Glancing-angle scattering of fast ions at solid surfaces

Abstract

The interaction of fast ions with solid surface is investigated by small angle scattering of MeV H +, He + and hydrogen molecular ions at grazing incidence on a clean (001) surface of SnTe single crystal. The secondary electrons with energies less than 25 eV shows an increase of the yield when the surface axial channelling occurs, while that of scattered ions shows a dip. This disappearance of the dip cannot be interpreted simply as due to the long dwell time of ions in the thin surface layer caused by surface channelling. The observed energy losses of the specularly reflected ions are 2 to 3 times as large as those calculated with the formula derived by Lucas. Anomalies in the charge state distributions of reflected ions are observed at specular reflection of incident ions at the surface. Further studies to elucidate the physical processes taking place at the surface are needed for the interpretation of these results.