Neutron Scattering from Light Water

The single differential cross section for neutron scattering from light water has been measured over the energy range 0.006 to 10 eV. The experimental techniques for making the measurement and correcting the data to obtain an absolute cross section are discussed. It is found that the multiple scattering of neutrons in the sample constitutes a large effect and procedures are utilized and tested for making this correction. The resulting cross sections are compared with predictions of theoretical models describing the molecular motion in water. These models include various versions of the free gas model, the Nelkin model, variations of the Haywood model, the McMurry model, and Radkowski prescription. Completely satisfactory agreement with the available neutron scattering data does not appear possible for any of the above models. The Haywood model seems to provide good agreement, however, for the widest range of data.