The diffusion of H (table 91) was monitored by using quasi-elastic neutron scattering, and measuring the width of the quasi-elastic line as a function of the scattering vector.

Quasielastic Neutron Scattering by Hydrogen in Niobium. W.Gissler, G.Alefeld, T.Springer: Journal of Physics and Chemistry of Solids, 1970, 31[10], 2361-9