Location of interstitial deuterium in TaDsub(0.067) by channeling

Ion channeling in connection with a nuclear reaction for a direct determination of the interstitial position of deuterium in TaDsub(0.067) at room temperature is used. 3He ions impinging on a deuterium doped Ta single crystal give rise to the resonant nuclear reaction D(3He,p)4He. The proton yield is plotted versus the scanning angle. In all axial cases, as well as in the (110) planar case, peaks for perfect alignment for octahedral and tetrahedral interstitial sites are observed. This proves that deuterium is an interstitial impurity. The yield profiles along (111) and (211) prove that the majority (>90%) of the deuterium atoms occupy the tetrahedral sites in the b.c.c. tantalum lattice