It was shown that lattice dislocations served as high-diffusivity paths for He in quartz. Synthetic crystals were grown so as to contain a certain amount of He, which was then de-gassed by heating. Synchrotron imaging was used to characterize and map the grown-in defects. Samples for desorption were prepared from chosen growth zones, for which the average dislocation densities were evaluated. In highly dislocated samples, the He appeared to be released more rapidly and to have a lower activation energy. The gain in diffusivity was attributed to the smaller amount of energy which was required to permit the passage of a He atom through the increased passage provided by a dislocation pipe.

X-Ray Imaging Study of Lattice Defects Related to Diffusion of Helium in Quartz. T.S.Argunova, L.M.Sorokin, B.Z.Pevzner, J.H.Je, Y.Hwu, W.L.Tsai: Journal of Physics D, 2003, 36[10A], A12-6