Measurements of 14.1 MeV Neutron Reflection and Transmission for Carbon, Polyethylene, and Steel

Fast and slow neutron return have been important in contributing to the effect of room return on unreflected subcritical and critical experiments. In addition, neutron reflectors are used with fissile material. As a first step in understanding fast neutron reflection, measurements were performed with time-tagged and directionally tagged 14.1 MeV neutrons from a D-T generator impinging on three common reflector materials. The time (energy) distribution of reflected fast neutrons was measured with respect to the emission of neutrons from the generator as a function of angle. Directional tagging assists in the removal of room return from these reflection measurements. In addition, the transmission was measured. This paper describes the experiment performed to characterize the neutron reflection and transmission for carbon, polyethylene, and steel. The experimental data presented in this paper can be used to assist in benchmarking calculational methods. (authors)