Alternatives to He-3 for neutron detectors
Presentation held at the 2nd Technical Meeting on Radiation Detection Instruments for Nuclear Security: Trends, Challenges, and Opportunities, 16. - 20. April 2018, Vienna
The shortage of He-3 led to a considerable increase in the price of certain safeguard equipment. Mayor effort has been put into the substitution of He-3 based detection technologies with technologies employing alternative isotopes for neutron detection. None of these technologies provide a real plug in substitute for the prevalent proportional He-3 tubes used in diverse Safeguard applications, but promising devices have been introduced into the market. Many new detection materials are based on Li-6 or B-10, several detectors employing these materials have been recently characterized at the Fraunhofer INT. Some of these new materials not only allow to detect neutrons, but to simultaneously register a gamma spectrum with the same detector, a feature which could enable interesting new methods for safeguard applications. We will present investigations and compare these with measurements of He-3 detectors, which still provide excellent efficiency and high Gamma discrimination capability. Depending on the operation purpose, advantages and shortcomings of some neutron detectors are discussed, especially with respect to easy exchange in existing systems.