G. Ernst

Pressure induced phonon frequency shifts in KBr measured by inelastic neutron scattering

Abstract Measurements of seven microscopic Gruneisen parameters in KBr by inelastic neutron scattering are reported and compared with several theoretical predictions.

Distortion induced by helium formation in tantalum-tritium systems

Two polycrystalline TaTx platelets, loaded with x = 4 and 11.5 at.% tritium (T), have been investigated by neutron scattering techniques for more than two years. The maximum 3He concentration resulting from radioactive tritium decay approaches 1.2 at.%. Changes of both positions and widths of the Debye-Scherrer lines are determined as a function of time. The lattice parameter is found to increase slightly with 3He concentration. The changes of the linewidths indicate the formation of growing dislocation networks. The data give evidence of an increasing anisotropic shear deformation of the bcc metal matrix in the TaT0.04 sample. Helium induced fracture of both platelets occurs already at concentrations below 1 at.%.