Parameterization Measurements of a 963 cm$^{3}$ LaBr$_{3}$:Ce Crystal*

LaBr$_{3}$:Ce is a relatively new scintillator with characteristics that surpass more commonly used radiation detection scintillators. Published results for small ($<$10 cm$^{3}$) LaBr$_{3}$ detectors (NIMA 683, 46, 2012) describe improved time resolutions ($\sim$35 ps), energy resolutions ($\sim$3.5\% at 662 keV), and optical yields ($\sim$63,000 photons/MeV) compared to NaI and BGO. Here it was possible to assess the characteristics of a 963 cm$^{3}$ (7.6 cm length, 12.7 cm diameter) cylindrical crystal optically coupled to an ET9390KB photomultiplier tube optimized for crystal emissions at 380 nm. A 3$\times$3 array of crystals will be used for neutron-stimulated evaluations of materials for elemental and chemical composition. A custom bleeder chain was designed to minimize current saturation and optimize the energy linearity over a 2-12 MeV energy range. Because large volume crystal characteristics do not always scale linearly, energy resolution, detector efficiency, crystal homogeneity, timing resolution, pulse shape, peak-to-Compton ratios, energy linearity, and self activity were all measured and compared to published results on other LaBr$_{3}$ detectors. Advantages and disadvantages of such large LaBr$_{3}$ crystals will be discussed, and future plans will be described.