Helium irradiation of alkali halides

An investigation has been made of radiation damage in alkali halide crystals induced by heavy bombardment of 1 MeV helium ions. The channeling technique has been employed and three processes have been monitored simultaneously to explain the apparent reduction of damage at high doses. It is shown that the initial rise and fall of the back-scattered yield from different alkali halides can be related to the Pooley mechanism coupled with the aggregation of interstitials to form dislocation loops through the intermediate stage of clusters