Computer Simulation of Displacement Cascade Structures in D--T Neutron-Irradiated Au, Ag, Cu, Ni and Al With the MARLOWE Code

Spatial distribution of point defects in displacement damage cascades at the early stage of their formation was simulated with the MARLOWE code for primary knock-on atoms which is relevant to D--T neutron irradiation. Calculations were carried out for Au, Ag, Cu, Ni and Al. Computer-simulated results were analyzed with complement of TEM observations of D--T neutron-irradiated metals at low temperature. The spatial configuration of displacement cascades, the size of small vacancy aggregates and the size of displacement damage cascade were examined. Results suggest that most of vacancy clusters which were formed in damage cascades may be as small as < 20 vacancies. The remarkable difference in defect yield of cascade damage in Ni and Cu is due to interstitial cluster formation and main contribution of cascade energy overlapping observed in cryotransfer TEM of D--T neutron-irradiated Au is due to ejected interstitials from cascade ores. Graphs, Photomicrographs. 12 ref.--AA(UK/US).