Helium diffusion in aluminium

Abstract

The diffusion in Al of reaction product He was measured by observing its rate of release from Al sheet on a mass spectrometer. Trapping of the He in Al was observed but prior to the trapping the diffusion coefficient was measured as: The average distance the He atoms must migrate in the Al to be trapped (obtained from the anneal curve shapes) depended on the anneal temperature and was ∼ 1 to 3 × 10−4 cm. This distance and its temperature dependence are best explained if He is trapped by diffusing to irradiation created vacancy clusters.