LaBr/sub 3/:Pr/sup 3+/ - a new red-emitting scintillator

In this communication we present our initial results on a LaBr₃:Pr³⁺ scintillator. The emission of this material under X-ray excitation shows multiple peaks in the range of 450 to 900 nm. The emission, due to transitions within 4f² configuration, although usually slow with decay time constants on the order of milliseconds, in the case of Pr³⁺ is much faster. The decay time constant of the overall emission at 1% doped sample was measured to be 11 mus. The time constant is concentration sensitive and decreases with increasing dopant content. The light output of the investigated samples was measured to be between 61,500 (APD) and 74,500 (PMT) photons/MeV. Thu energy resolution at 662 keV was dependent on the type detector employed. The best energy resolution measured with moderately cooled silicon detector was as low as 3.2%. Since the choice of red-emitting scintillators is rather limited LaBr₃:Pr³⁺ is a very interesting scintillator that could help to fill this gap. Particularly it is suitable for silicon detectors