INTERSTITIAL SITE OCCUPATION IN ALPHA-LANI5-H STUDIED BY DEEP-INELASTIC NEUTRON-SCATTERING

Deep inelastic neutron scattering (DINS) from hydrogen is a new techni que made possible by the advent of accelerator-based neutron sources s uch as ISIS at the Rutherford Appleton Laboratory. DINS measures both the concentration and the mean kinetic energy of hydrogen in the sampl e. H concentrations of less than 1% relative to the metal can be measu red, since the hydrogen signal is well separated from the metal signal . In situ measurements on un-cycled alpha-LaNi5-H revealed that the sa mple contained trapped hydrogen after desorption. The changes in H con centration measured with DINS were in good agreement with manometric m easurements. The I-I kinetic energy did not change significantly with concentration, suggesting that the trapped and untrapped H atoms occup y essentially the same interstices.