Radiation-induced diffusion of point-defects during low-temperature electron irradiation

Abstract

Abstract Electron irradiation damage in lead was studied in a high-voltage electron microscope at temperatures between 8 and 300 K. The formation and growth of interstitial clusters was observed during irradiation at temperatures between 8 and 165 K and of vacancy clusters between 50 and 165 K, i.e. at temperatures well below annealing stage III (at ∼170K in lead). The observation of vacancy cluster growth is interpreted as evidence for preferential absorption of interstitials at sample surfaces. By a combination of above-and sub-threshold irradiations and in situ annealing treatments it could be shown that the point-defect motion responsible for cluster formation below Stage III is of radiation-induced nature. The importance of radiation-induced diffusion for the low-temperature irradiation and the annealing behaviour of lead and gold is discussed. Various mechanisms which may be responsible for radiation-induced defect migration and its main characteristics are considered.