Measurements and Single-Velocity Calculations of Differential Angular Thermal-Neutron Albedos for Concrete

Single-velocity Monte Carlo calculations and measurements have been performed to determine the differential angular thermal-neutron albedos for a reinforced concrete for monodirectional beams of incident thermal neutrons. Preliminary calculations using a statistical estimation technique indicate up to 50 scatterings should be followed for each neutron to produce good estimates of the differential albedos, and up to 100 scatterings to produce good estimates of the capture gamma-ray differential dose albedos. Deviation between experiment and calculation can be reduced to an average of 5.1% for 72 points of comparison if an anisotropic scattering law for water deduced from earlier Argonne National Laboratory measurements is assumed.