Resolution analyses for Moessbauer diffraction: Resolved TDS profiles in silicon

The resolution function for Moessbauer γ-ray scattering and the thermal diffuse scattering (TDS) near the 444 reflection in silicon have been measured with high-intensity Moessbauer radiation from the 46.48 keV transition in 183W. A general analysis of the resolution function has been carried out for the first time which shows that its energy and momentum components can be factored independently with the energy resolution being determined by the Moessbauer resonance. The half-widths of the momentum resolution ellipsoid were measured to be 0.011, 0.11 and 1.13 A-1 in the transverse, longitudinal and vertical directions, respectively. The ratios of these half-widths are significantly different from those commonly encountered in neutron scattering. These analyses indicate that the observed broad distribution of inelastic scattering in the TDS profiles is consistent with published elastic constants for silicon. (orig.)