ACCUMULATION PROCESSES OF CASCADE DAMAGE UNDER HEAVY-ION IRRADIATION

In-situ observation of defect clusters was performed to examine cascade damage produced by energetic heavy particle in gold. Thin foils of pure gold were irradiated with 400 keV Xe+ ions using a combined facility of a 400 kV heavy ion accelerator and a 200 kV transmission electron microscope (TEM). TEM images of defect clusters under irradiation were recorded on videotapes, and ion fluence dependence of the defect cluster density, production and annihilation efficiencies of defect clusters were measured on the video images. Defect cluster density under irradiation was determined by the balance between the production and the annihilation of defect clusters. A simple model of accumulation processes of cascade damage was proposed.