PNNL

Abstract

Neutron detection is an integral part of the global effort to prevent the proliferation of special nuclear material (SNM). Applications relying on neutron-detection technology range from traditional nuclear non-proliferation objectives, such as safeguarding nuclear material and verifying stockpile reductions, to the interdiction of SNM—a goal that has recently risen in priority to a level on par with traditional applications. Large multi-national programs targeting detection and safeguards have deployed radiation-detection assets across the globe. Alongside these deployments of commercially available technology, significant research and development efforts have been directed towards the creation of next-generation assets. While much of this development has focused on gamma-ray spectrometers, neutron-detection technology remains an important component of the global strategy because of the capability of neutrons to penetrate materials that readily absorb gamma rays and the unique multiplicity signatures offered by neutrons. One particularly acute technology-development challenge results from dwindling supplies of 3He, partially triggered by widespread deployment of high-efficiency systems for portal monitoring. Other emerging missions, such as the desire to detect SNM at greater standoff distances, have also stimulated neutron-detection technology development. In light of these needs for novel neutron-detection technologies, this manuscript reviews the signatures of neutrons emitted by SNM, the principles of neutron detection, and various strategies under investigation for detection in the context of nonproliferation.