Lattice Parameter Changes in Deuteron-Irradiated Germanium

A lattice expansion of 3×${10}^{-5\mathrm{}}$ was measured in germanium irradiated by 1.5×${10}^{17}$ 9-Mev deuterons/${\mathrm{cm}}^2$ at low temperature and annealed to 320°K. Thus residual specimen length expansion (as measured by Vook and Balluffi in similar samples) and lattice parameter expansion are small and nearly equal after annealing to room temperature. Thermal recovery to 380°K occurred parallel to that of macroscopic length changes, but near 380°K the (211) interplanar spacing had contracted about 3×${10}^{-5\mathrm{}}$ relative to unirradiated crystal. The lattice parameter returned to that of unirradiated crystal at 430°K. No appreciable diffraction line broadening was observed. These results provide confirmatory evidence that structural damage in deuteron-irradiated germanium consists of well-localized centers of dilatation.