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.