The diffusion of He in single crystals was studied by analyzing He desorption from previously saturated specimens. The results (table 81) could be described by:

D (cm2/s) = 2.0 x 10-2 exp[-0.39(eV)/kT]

A.N.Varaksin, P.V.Volobuev, L.V.Gulin: Fizika Tverdogo Tela, 1975, 17[12], 3579-84

 

 

Table 81

Diffusivity of He in KCl Single Crystals

 

Temperature (K)

D (cm2/s)

623

1.41 x 10-5

673

2.72 x 10-5

723

4.3 x 10-5

773

5.0 x 10-5

823

9.1 x 10-5