CeBr3-PrBr3 scintillators

Recently a new halide scintillator was shown to exhibit interesting properties. Birowosuto et al. reported that PrBr₃:Ce provides between 16,000 and 21,000 photon/MeV depending on the Ce concentration, and shows shorter than 10 ns decay time constant. In this presentation we report on some of the scintillation properties of the CeBr₃-PrBr₃ scintillators. We grew crystals containing from 99% of CeBr₃, 20% down to 2% and 1%. The results obtained for the two last crystals coincide well with these described by Birowosuto. The highest light output out of the all tested samples is about 19,800 photons/MeV (2% Ce) and shows dependence on the sample size (height). The non-proportionality of the low concentration samples shows deviation from the linearity. Between 662 and 60 keV, the deviation is around 6% (2.5 mm thick sample) and it increases with the sample size. The shortest principal decay time constant measured is 9 ns (1% Ce, 2% Ce). The rise time constant was estimated to 1.2 ns. Scintillation decay of 20% Ce sample showed longer, 24 ns time constant. The best time resolution measured was 210 ps (FWHM) for a thin 2% Ce sample. In comparison two LaBr₃:5% Ce provided 160 ps (FWHM) on the same setup.