Neutron-Spectrum Measurements in H₂O and D₂O

Spatially dependent neutron-spectrum measurements have been made in both light and heavy water, using the General Atomic Linear Accelerator Facility and standard time-of-flight techniques. The measurements were made with varying geometrical arrangements, and both 1/v and resonance absorbers were utilized to simulate reactor poisons. The measurements were compared to calculations performed with an S_N transport code utilizing the bound scattering models proposed for these moderators. The agreement between theory and experiment for the Nelkin model for H₂O and Honeck&pos;s extension of this model to D₂O is shown to be very satisfactory for the cases studied.