Experimental Verification of Neutron and Gamma-Ray Transport Calculations in Lithium Hydride and Tungsten.

Abstract : Measurements of the neutron angular flux spectrum from approximately 0.1 eV to 15 MeV were made in a 91.4-cm diameter sphere of lithium hydride, using the pulsed-source, time-of-flight method. These measurements were compared with 05R Monte Carlo and DTF-1V discrete ordinates calculations to test computational methods and nuclear data for LiH shields. The fast neutron data for LiH appear to be rather good except for the angular distributions. The discrete ordinates code underpredicts the low-energy flux. An assymetrical quadrature set was developed to reduce computer storage requirements for the discrete ordinates calculations. Measurements of the neutron angular flux spectrum below 200 eV and the secondary gamma-ray spectrum from 200 keV to 10 MeV were made in a laminated sphere of tungsten and lithium hydride. Discrepancies were noted between measurement and DTF-IV neutron calculations especially in the tungsten at the energies of strong resonances. A secondary gamma ray source code was written and calculations of gamma ray production and transport were performed. (Author)