Measurements were made of the mobility (diffusion and trapping) of heavy rare gas in pure and CaCl2-doped single crystals, following ion bombardment to integrated doses of 108 to 2 x 1016/cm2 using energies of between 30 and 500keV. No obvious effect of doping upon release was found. At low gas concentrations, the release was compatible with volume diffusion; involving an activation enthalpy of 1.5eV. This value was obtained for very low and very high bombardment energies (1 and 500keV); thus indicating that the same release mechanism operated near to the surface and in the bulk. At higher gas concentrations, the release shifted towards higher temperatures. This retarded release was attributed to transient trapping and was shown to have a partially single-jump nature. The result was again the same for both low and high bombardment energies.

Rare Gas Diffusion in Sodium Chloride. H.J.Matzke, G.Rickers, G.Sorensen: Zeitschrift für Naturforschung, 1969, 24a[5], 820-6