The permeation of 222Rn through annealed and cold-worked material was studied, at temperatures ranging from 30 to 150C, by means of α-spectroscopy. It was found that virgin annealed Au was impermeable to 222Rn at temperatures of up to 150C, but was made permeable by thermal cycling. Virgin cold-worked material was highly permeable at room temperature. Prolonged isothermal treatment produced permeation plateaux in annealed material, but permeation peaks in cold-worked material. The activation energy for permeation in cold-worked material was between 18.0 and 22.5kJ/mol. The activation energy for permeation in annealed material was between 33.2 and 35.4kJ/mol. The results were explained in terms of the capture of vacancies by diffusing 222Rn, and changes in diffusion paths due to deformation.

Highly Sensitive Measurements of 222Rn Permeability in Au S.K.Bhattacharyya, S.K.Pabi: Journal of Nuclear Materials, 1997, 245[1], 44-51