MEASUREMENT OF NEUTRON PENETRATION STANDARDS. VOLUME I. ANGULAR NEUTRON AND GAMMA-RAY SPECTRUM MEASUREMENTS IN A BULK IRON ASSEMBLY.

Abstract : A comprehensive study has been made of the neutronic behavior in iron. The research comprised measurements of the neutron angular flux spectrum from approximately 1 keV to 10 MeV in a 76.2-cm-diameter iron sphere, the gamma-ray spectrum from 0.20 to 10.0 MeV in the same bulk assembly, and the gamma-ray time distribution. In addition, the total cross section of iron has been measured from 0.5 MeV to 10 MeV with a 0.035 nsec/m resolution. The neutron angular flux spectra are compared to a series of discrete-ordinates transport calculations using ENDF/B, P3 cross sections in both 29- and 49-group representations. Both calculations indicate that the present ENDF/B data for iron are wrong by as much as fifty percent in some energy regions. (Author)