High energy resolution scintillation spectrometers

In this paper, we report on cerium doped scintillator-LaBr₃ : Ce for gamma ray spectroscopy. Crystals of this scintillator have been grown using the Bridgman process. This material when doped with cerium has high light output (>60 000 photons/MeV) and fast principal decay constant (<30 ns). The peak of LaBr₃ : Ce emission is at 360 nm. LaBr₃ : Ce shows excellent energy resolution for gamma ray detection. For 662 keV gamma rays (¹³⁷Cs source), energy resolution of 2.6% (full-width at half-maximum) has been recorded at room temperature for LaBr₃ : Ce crystals coupled to a photomultiplier. This energy resolution is over two times better than that of NaI(Tl) scintillators. Analysis of the energy resolution of LaBr₃ : Ce scintillators is presented. Energy resolution of LaBr₃ : Ce crystals coupled to silicon avalanche photodiodes is also discussed.