Bismuth- and lithium-loaded plastic scintillators for gamma and neutron detection

Abstract

Transparent plastic scintillators based on polyvinyltoluene (PVT) have been fabricated with high loading of bismuth carboxylates for gamma spectroscopy, and with lithium carboxylates for neutron detection. When activated with a combination of standard fluors, 2,5-diphenyloxazole (PPO) and tetraphenylbutadiene (TPB), gamma light yields with 15 wt% bismuth tripivalate of 5000 Ph/MeV are measured. A PVT plastic formulation including 30 wt% lithium pivalate and 30 wt% PPO offers both pulse shape discrimination, and a neutron capture peak at ~400 keVee. In another configuration, a bismuth-loaded PVT plastic is coated with ZnS(6 Li) paint, permitting simultaneous gamma and neutron detection via pulse shape discrimination with a figure-of-merit of 3.8, while offering gamma spectroscopy with energy resolution of R(662 keV) = 15%.

Investigation into the potential of GAGG:Ce as a neutron detector

“…If 6 Li and 10 B are loaded into scintillators the achievable loading fraction is limited by degradation of the scintillation characteristics [20,21]. In comparison, the thermal neutron capture cross section of gadolinium coupled with its mass fraction in GAGG means that relatively small crystals offer almost 100%…”

Plastic scintillators modifications for a selective radiation detection

“…Concerning gamma-rays identification, the best results are obtained with bismuth(III) organometallics as dopants. Triphenyl bismuth, triaryl [10,11] and tricarboxyl bismuth complexes [10,12] have been reported. With such loading, the apparition of the photoelectric peak was observed for high energy X-rays and gamma below 200 keV, as well as in synchrotron conditions [13] by several groups around the world.…”

Transparent plastic scintillators for neutron detection based on lithium salicylate

“…al. [17]. Even though the thermal neutron capture cross section of 6 Li is lower than that of 10 B (942 vs 3840 barns, respectively [2]), 6 Li may have advantages as compared to 10 B in PSD plastics.…”