Use of an LGB detector in nuclear nonproliferation applications

Capture-gated detectors have attracted the attention of several researchers because of their promise for neutron spectroscopy in mixed neutron-gamma-ray fields. Examples are the boron-loaded detector (loaded with either natural B or B enriched in B-10), the Li-6-glass/plastic scintillation detector, and the lithium-gadolinium-borate (LGB) detector (loaded with Li-6, natural Gd, and B-10). In the work presented in this paper, the LGB plastic scintillation detector is investigated. This detector is sensitive to not only fast neutrons and gamma rays, but also to thermal neutrons. Some efforts have been made in the past to characterize this detector for several neutron and gamma-ray energies. In this paper, we compare measurements and Monte Carlo simulations for the LGB detector. In the comparisons, very good agreement is achieved, which indicates accurate Monte Carlo modeling. This work has applications in fields such as nuclear safeguards, nuclear nonproliferation, and national security.