Annealing of defects induced by Ge irradiation of silica probed with variable energy positrons

Fused silica (Suprasil 2) has been implanted with 2 MeV Ge ions. Defects produced by the implantation have been studied using a variable energy positron beam. The measurements allow depth resolved characterisation of the implantation induced defects, which are found to be produced by both the electronic and nuclear stopping of the ions. It is suggested that the previously unidentified positron-trapping defect associated with the nuclear …