Anomalous scattering of keV neutrons from H2O and D2O:: I.: Single scattering events

Scattering of neutrons in the 24-150 keV incident energy range from H2O relative to that of D2O and H2O-D2O mixtures was reported recently by Moreh et al. This work is related to neutron Compton scattering experiments regarding the 'anomalous' scattering from protons, observed earlier at ISIS by Chatzidimitriou-Dreismann et al in the 5-100 eV range. Here we provide the complete data reduction scheme of time-of-flight integrated intensities measured at keV energy transfers, within the impulse approximation of standard theory and for single scattering events. Current investigations of multiple scattering events and the associated preliminary results are mentioned. Direct application of the theoretical results to the new keV scattering data reveals an anomalous ratio of scattering intensity of H2O relative to that of D2O of about 20%, thus being in good agreement with the earlier results of the original experiment at ISIS.