Target preparation

Abstract

The requirements for the surface preparation of single crystals to be used in the measurement of heavy ion channelling, proton scattering, etc., processes which depend on the ordered nature of the lattice, are much more stringent than those for the standard metallographic examination of surfaces. This review describes the various techniques of sectioning, grinding and polishing of single crystals, illustrates the type and depth of damage introduced as a consequence of these techniques and shows how this damage may best be removed. The mounting of prepared targets in vacuum apparatus, in a manner suitable for measurement of channelling effects over a wide range of temperature is described and illustration is made of the effect of disordered surfaces, due to oxidation or to ion bombardment, on the measured yield of the channelling processes.