Sensitivity of a Paraffin-Moderated BF₃ Proportional Counter

Abstract

The sensitivity was obtained by solving a multi-group diffusion equation and by the experiment using monoenergetic neutrons. The neutron energies used were over the range of 0.625 eV to 10 MeV in the calculation and 5 KeV to 6 MeV in the experiments. Moderator thicknesses were 2.7, 4.7, 6.7, 7.9, 11.0 and 14.7 cm in the calculation, and 3.5, 4.5, 6.5, 8.5 and 14.0 cm in the experiments. The results show a good agreement between the experimental and theoretical sensitivities for the energies above 200 KeV, while slight discrepancies appear below this energy.

Measurements of Streaming Neutrons on Nuclear Ship “Mutsu” by a Two-Detector-Method

“…Fig. 3 Geometry of BF 3 counter in detector arrangements A, B and C Thermal neutrons were counted by the detector arrangement A. The arrangement B was intended to measure mainly the neutrons of intermediate energy, and the arrange.…”

“…of detectors sensitive to thermal neutrons such as BF 3 proportional counters, the same does not apply to neutrons in the epi-thermal and fast regions, where such techniques as neutron activation will not suffice to provide the required information.…”

“…( i ) Sub-Cd neutron flux:(2)(3)(4)(5)(6) x 10 2 (n/cm 2 ·sec) (ii) Epi-Cd neutron flux: (4-9)x 10 2 (n/cm 2 ·sec) (iii) Sub-Cd neutron DER: (0.6-2 . ..1) (mrem/hr) (iv) Epi-Cd neutron DER: (10-30) (mremjhr)…”