Bulk diffusion in electron-irradiated single crystals was studied at 650 to 850C. The results could be described by:

D (cm2/s) = 2.1 x 101 exp[-48.0(kcal/mol)/RT]

G.V.Dudko, N.I.Marunina, G.V.Sukhov, D.I.Cherednichenko: Fizika Tverdogo Tela, 1970, 12[4], 1292-4