Isotopes of He were produced in single crystals via the nuclear reaction, 6Li(n,3H)4He, and the decay of 3H to 3He. The isotopic ratios of the out-gassed He isotopes were measured at a constant temperature of 620C. The ratio of the diffusion constants was found to be 1.02 at most. This was considerably smaller than the classical maximum value of 1.155.
Diffusion of He-3 and He-4 in LiF. S.Kalbitzer, J.Kiko, J.Zähringer: Zeitschrift für Naturforschung, 1969, 24a[12], 1996-2000
Table 167
Self-Diffusion of Li in LiF Single Crystals
Temperature (C) | D (cm2/s) |
550 | 8.00 x 10-11 |
600 | 1.49 x 10-10 |
650 | 3.88 x 10-10 |
700 | 1.33 x 10-9 |
750 | 3.55 x 10-9 |
800 | 1.15 x 10-8 |