Boron Trifluoride Proportional Counters

Abstract

Boron trifluoride proportional counters of calculable efficiency for neutron beam measurements are described. It has been found possible to obtain excellent pulse-size distributions with a filling of 60 cm of purified BF3 by ``soaking'' the counters for a long time (up to three months) with BF3 before putting in the final filling. These fillings are stable. Fillings of less than 5 cm BF3 made up to 50 cm with argon have also been studied. With these fillings the pulse-size distributions are very good for both beam and total irradiation conditions. A discussion of the counter efficiencies with particular reference to end correction is given.

A theoretical analysis of the neutron scattering method of measuring snow and ice density

“…CE = 1 if the counting period is accurate and all the pulses produced by neutron absorption are detected. Fowler and Tunnicliffe [1950] have reviewed the factors which may lead to the production of pulses of uneven size, especially in boron trifluoride detectors filled to near atmospheric pressure. Depending on the voltage threshold used in the counting circuit, some small pulses may not be counted and the value of CE may therefore be less than 1.…”

Mitigation of backgrounds from cosmogenic 137 Xe in xenon gas experiments using 3 He neutron capture

“…We may also consider alternative gases that have been explored to play a similar role to 3 He in the face of limited supply. BF 3 enriched in 10 B is one attractive possibility [59][60][61][62][63].…”

High intensity neutron diffractometer

“…We built proportional BF 3 counters of a design [8] differing from that generally used in such work [9]. This improved construction leads to a greater sensitivity, in fact very near to 100% for a thermal neutron beato travelling parallel to the axis of the counter tube [8,10].…”