Helium-3 filled cylindrical proportional counters are efficient, reliable neutron detectors with excellent gamma rejection capability. In recent years, the reduction in He-3 production and continuing high demand has led to a He-3 shortage. This shortage has caused the detectors to become prohibitively expensive and difficult to obtain. The goal of this project is to test and evaluate current alternatives produced for some applications and deployed by two private companies. Current testing is being done with a Lithium Zinc Sulfide (~6LiF:ZnS(Ag)) detector from Aspect, as used in their portal monitors, as well as a Boron Coated Straw (BCS) coincidence counter from Proportional Technologies Inc. Specific features such as radial response (the response of the detector as a source moves past the face) and gamma rejection were tested with the detectors mentioned above, as well as comparisons to a current ~3He module through experimental measurements.
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