Lawrence Berkeley National Laboratory

In this paper, we report on a relatively new scintillator - LaBr3 for gamma ray spectroscopy. Crystals of this scintillator have been grown using Bridgman process. This material when doped with cerium has high light output (~;60,000 photons/MeV) and fast principal decay constant (less than 25 ns). Furthermore, it shows excellent energy resolution for gamma-ray detection. Energy resolution of 3.2 percent (FWHM) has been achieved for 662 keV photons (137Cs source) at room temperature. High timing resolution (260 ps - FWHM) has been recorded with LaBr3-PMT and BaF2-PMT detectors operating in coincidence mode using 511 keV positron annihilation gamma-ray pairs. Details of its scintillation properties, and variation of these properties with changing cerium concentration are reported. Potential applications of this material are also addressed.