A contribution to sputtered ejection patterns from collision sequences in atomic cascades: Firm evidence from channeling experiments

Abstract

The sputtering of single crystals of radioactive gold by well collimated beams of energetic ions has been investigated in detail, using cylindrical collectors. For 80 keV argon ions incident in and near to channels there is a very sensitive dependence of the height and shape of the spots on angular deviation. This is shown to be a consequence not only of the size and degree of order within anatomic cascade, but also of its position below the bombarded surface, following ion dechannelling. At angles of incidence such that cascades lie at very shallow depths the spots develop an internal structure, which is shown not to be an artefact, but can be due to not fully focused collision sequences, from the cascade. Detailed variations in spot structure and relative intensities for beams incident at and near to axial and {100} planar channels are also described, as are the influences of incoming ion energy.