A Novel Boron-Loaded Liquid Scintillator for Neutron Detection

Abstract

A boron-loaded liquid scintillator (LS) has been optimized for neutron detection application in a high gamma field environment. It is composed of the solvent linear alkylbenzene (LAB), a boroncontaining material, o-carborane (C2B10H12); a fluor, 2,5-diphenyloxazole (PPO); and a wavelength shifter, 1,4-bis[2-methylstyryl] benzene (bis-MSB). Preparation of the liquid scintillator and optimization of its chemical composition are described. The boronloaded LS has been tested with a neutron beam at the National Research Universal (NRU) reactor. A peak at an equivalent energy of 60 keV is observed in the energy spectrum and is attributed to neutrons. The results confirm the possibility of using B-10 loaded scintillator as a sensitive medium for neutron detection in a relatively large background of gamma rays.

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“…The loss of scintillation light yield when switching from a PC-based scintillator to a LAB-based scintillator is limited: the yield reported for LAB+PPO+bisMSB is 70 % of that of PC+PPO [134] and it can be compensated, where needed, by a modest increase in the number of PMTs. A recent development [135] identified the possibility of loading organic liquid solvents with an organoboron compound of fairly limited safety and environmental impact: ortho-carborane, (1,2-Dicarbadodecaborane( 12), C 2 B 10 H 12 ), a solid at room temperature with a melting point of 260 • C, can be dissolved in LAB and also in DIN up to a concentration of 8.5 % in weight [136], thus providing a safer alternative to TMB. Another nucleus with large neutron capture cross section is 6 Li.…”