BF3 Counters for Use in Field Instrumentation

A number of different neutron detectors employing arrays of BF3 counters in hydrogenous moderators have been constructed and tested in the field. Some of the problems of obtaining BF3 counters with matching mechanical and electrical characteristics from commercial manufacturers are briefly reviewed. Several unexpected problems which arise when BF3counters are not used in a controled environment are discussed. A transient sensitivity to gamma rays in some counter designs immediately after the application of high voltage is noted and explained. A technique for reducing spurious counts due to humidity effects by coating the ceramic high voltage insulators with Teflon is described. Spurious counts due to inverting and vibrating the BF3 counters are examined for different sizes of counters.