Bridgman growth of LaBr3:Ce and LaCl3:Ce crystals for high-resolution gamma-ray spectrometers

Single crystals of LaBr3:Ce and LaCl3:Ce have been grown by the vertical Bridgman technique. Crystals of these scintillators are used in the fabrication of high-resolution, gamma-ray spectrometers. The LaBr3:Ce and LaCl3:Ce crystals we have grown have high light outputs of ∼80,000 and 50,000 photons/MeV, respectively, and fast principal decay constants of <30 ns. The emission wavelength for the LaBr3:Ce and LaCl3:Ce scintillators are λmax=360λmax=360 and 350 nm, respectively. Both materials have excellent energy resolutions of ∼3% FWHM for 662 keV photons at room temperature. In this paper, we will report on our results to date for vertical Bridgman crystal growth and characterization of Ce-doped LaBr3 and LaCl3 crystals. We will also describe the handling and processing procedures developed for these oxygen and moisture sensitive materials.