The kinetics which drove cascade formation and subsequent collapse were investigated by analysing the microstructures which were produced in situ by low-fluence 100keV Kr-ion bombardment of face-centered cubic samples at 18 to 873K. The resultant microstructures were characterized by quantitative measurements of the yields of collapsed point-defect clusters. The defect yields were shown definitely to be temperature dependent. They remained approximately constant up to 573K, and then suddenly decreased with increasing temperature. This yield drop was not caused by defect-loss during, or following, ion irradiation. It instead reflected a decrease, in the probability of cascade collapse, which could be explained by a thermal spike effect.

In-situ Transmission Electron Microscopy Study of Ion-Irradiated Copper - Temperature Dependence of Defect Yield and Cascade Collapse. T.L.Daulton, M.A.Kirk, L.E.Rehn: Philosophical Magazine A, 2000, 80[4], 809-42