The samples were prepared by the implantation of 380keV 6Li+ ions into W and Ta thin foils (up to a fluence of 1016/cm2), and were annealed at up to 1940C. The depth profiles of 6Li were determined by using the thermal neutron depth profiling technique. The results showed that the diffusion of 6Li in both the W and Ta foils was very complex and could not be described by simple Fick’s laws. Trapping centers in the sub-surface layers of W and Ta were suggested to explain the 6Li diffusion behavior. However, the 6Li depth profiles were only partly explained. It was concluded that other aspects had to be taken into account, such as spatially-dependent diffusion coefficients.

Diffusion of 6Li in Ta and W. J.Vacik, V.Hnatowicz, U.Köster, J.Cervena, V.Havranek, G.Pasold: Nuclear Instruments and Methods in Physics Research B, 2006, 249[1-2], 865-8