Neutron sensitivity of 10B4C-coated aluminum honeycomb using a single-anode wire, P-10 continuous-gas-flow proportional counter

Abstract

The intrinsic thermal-neutron detection efficiency of a 10B4C-coated aluminum honeycomb sample was measured using a single-anode wire, P-10 continuous-gas-flow proportional counter. The aluminum honeycomb sample was 1.27 cm thick with a diameter of 4.1275 cm (1 5/8 in.) and was composed of hexagonal-shaped cells with a cell size of 1.5875 mm (1/16 in.). The 10B4C coating was applied by Exothermics, Inc. via magnetron sputtering to a coating thickness of 4.68±1.25μm as measured using a scanning electron microscope. Using a lower level discriminator setting of 50 keV, intrinsic thermal-neutron detection efficiency was measured to be 21.45 ± 0.26% in reference to a 4.0 atm, 5.08-cm (2-in.) diameter, 15.24-cm (6-in.) long Reuter Stokes 3He tube with a known efficiency of 80.7 ± 0.5%. MCNP6 simulations yielded a theoretical intrinsic thermal-neutron detection efficiency of approximately 24% for a 10B4C-coating thickness of 4.68μm with a lower level discriminator setting of 50 keV.