The present invention provides a new scintillator, cerium bromide (CeBr.sub.3), for gamma ray spectroscopy. Crystals of this scintillator have been grown using the Bridgman process. In CeBr.sub.3, Ce.sup.3+ is an intrinsic constituent as well as a luminescence center for the scintillation process. The crystals have high light output (.about.68,000 photons/MeV) and fast decay constant (.about.17 ns). Furthermore, it shows excellent energy resolution for .gamma.-ray detection. For example, energy resolution of <4% (FWHM) has been achieved using this scintillator for 662 keV photons (.sup.137Cs source) at room temperature. High timing resolution (<200 ps-FWHM) has been recorded with CeBr.sub.3-PMT and BaF.sub.2-PMT detectors operating in coincidence using 511 keV positron annihilation .gamma.-ray pairs.