DIFFERENTIAL NEUTRON CURRENT ALBEDOS FOR CONCRETE IN THE INCIDENT ENERGY RANGE 0.5 eV TO 200 keV. Ⅰ. DESCRIPTIONS OF MONTE CARLO CALCULATION AND TSF EXPERIMENT AND COMPARISON OF CALCULATED AND EXPERIMENTAL RESULTS

摘要

Extensive Monte Carlo calculations were performed to determine the distribution in energy and angle of neutrons reflected from steel-reinforced concrete for five incident directions and ten incident energy groups extending from 0.5 eV to 200 keV. The reflected distributions were determined in terms of a doubly differential albedo for each of 54 emergent directions for each energy group lying between and including the incident group and the tenth group (0.5 to 1.8 eV). The standard deviation of the doubly differential albedo averaged around 10％. The angular slowing-down density of the incident epicadmium neutrons within the slab was computed at 0.5 eV and used as the source distribution for a Monte Carlo single-velocity diffusion calculation using 0.025-eV cross sections.