The Neutron Spectrum from a Fission Source in Water

Time-of-flight measurements of the neutron angular flux spectrum in water have been made to provide a standard of comparison for neutron penetration calculations. The spectrum from 0.002 eV to 12 MeV was measured with an accuracy of ±10 to ±30% and a resolution of 5 to 15%, at angles from 0 to 90 deg and penetrations to 38 cm. Comparisons with discrete ordinates calculations using ENDF/B and GAM-II cross sections indicate fairly good agreement.