Atoms were implanted into the solid at a known depth, and the time required for their random walk through a selvedge to reach the surface was measured at 1900K. It was demonstrated that the diffusion coefficient was independent of the distance to the (110) surface. The results could be described by:

D (cm2/s) = 2.9 x 10-4 exp[-3.80(eV)/kT]

E.G.Overbosch, A.D.Tenner, J.Los: Radiation Effects, 1980, 53[1-2], 73-80