The Monte Carol Simulation of Neutron Tramsmitted and Scattered by Disk Choppers of Various Compositions

摘要

We consider the transmission of neutrons through disk-type neutron choppers, considering both the uncollided neutron fraction (PHI_u) and scattered neutron fraction (PHI_s). We computed PHI_u, PHI_s, and the ratio PHI_u/PHI_s through plates of five different absorber materials of various thicknesses to give information for selecting optimum materials and thicknesses. We also studied variance-reducing techniques for Monte Carlo calculation of chopper using MCNP4b, selecting those most effective for these calculations.