Coherent neutron scattering by light water (H2O) and a light-heavy water mixture (64 per cent H2O/36 per cent D2O)

Abstract

Measurements have been made, with high statistical accuracy, of the differential scattering cross-section for 1·06 Å neutrons by light water and a special mixture of light and heavy water at 22°C. For light water, the structure in the scattering pattern is attributed mainly to coherent scattering; a structure factor has been obtained over a limited range of momentum transfer. For the chosen mixture, the protons and deuterons give no contribution to the coherent scattering and a structure factor has been obtained which corresponds very well to the oxygen-nucleus structure factor obtained from X-ray data. The results show the desirability of extending these high accuracy measurements using isotopic substitution methods as a means of obtaining the three partial structure factors for water. The method of isotopic mixtures is applicable to a wide range of proton containing liquids.