Neutron-Deuteron Scattering Amplitudes

Abstract

The diffraction of neutrons from deuterium containing compounds gives the coherent scattering section of deuterium which can be used to determine the spin dependent scattering amplitudes. Studies have been made on a number of deuterium containing compounds but the results reported here are concerned primarily with recent measurements on NaD. X-ray measurements have been used in interpreting the thermal vibration effects in the crystal and use has been made of Na scattering cross-section data obtained from various sodium containing compounds. This experiment gives ${\sigma }_{\mathrm{coh}}=5.2\mathrm{}\pm 0.3$ barns. This value can be combined with the results of other deuterium cross-section measurements to give pairs of values for the individual quartet and doublet spin amplitudes for $n-d$ scattering. Various experimental results bearing on this point are summarized. Recent theoretical work seems to have eliminated the ambiguity in the experiments with regard to which of two sets of values of the spin amplitudes is to be chosen.