Neutron response functions of the multisphere moderated BF3 counter

Presented are experimental and theoretical determinations of multisphere moderated BF3 counter responses. Eight spheres are used with different thicknesses ranging from 1 to 14 cm of polyethylene moderators, and the central thermal neutron detector is a 2 inch diameter BF3 counter. The counter responses were measured for thermal and monoenergetic neutrons of energies 0.051, 0.144, 0.350, 0.565, 1.20, 2.50, 5.0, 15.2MeV. Calculations of the counter responses were also carried out by using one-dimensional discrete ordinates transport code, ANISN-JR. The experimental and theoritical results were in a good agreement except in the case for 1 cm thickness of moderator at neutron energies higher than 2.5MeV. Energy response functions were finally estimated by using the experimental and calculated results. The measured and calculated sensitivities of the counter for 252Cf neutrons also showed good agreements. (author)