Manometric measurements were used to study He removal from crystals which had previously been saturated with He at a higher temperature. From the results, it was deduced that the He diffusivity at temperatures ranging from 300 to 500C could be described by:

D (cm2/s) = 6.0 x 10-6 exp[-5050/T]

N.N.Alekseenko, P.V.Volobuev, P.E.Suetin: Fizika Tverdogo Tela, 1972, 14[8], 2398-400

Table 125

Diffusion of HCl in NaCl Melts