Neutron sensitivity of ~(10)B_4C-coated aluminum honeycomb using a single-anode wire, P-10 continuous-gas-flow proportional counter

摘要

The intrinsic thermal-neutron detection efficiency of a (B4C)-B-10-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 (15/8 in.) and was composed of hexagonal-shaped cells with a cell size of 1.5875 mm (1/16 in.). The (B4C)-B-10 coating was applied by Exothermics, Inc. via magnetron sputtering to a coating thickness of 4.68 +/- 1.25 mu m 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 He-3 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 (B4C)-B-10-coafing thickness of 4.68 mu m with a lower level discriminator setting of 50 keV.