New Intrinsic Fast Scintillator: Cesium Praseodymium Chloride

A sample of Cs3PrCl6 crystal was grown under vacuum using the vertical Bridgman- Stockbarger method. The excitation spectrum, monitored at an emission wavelength of 310 nm, showed at least two excitation bands at around 233 and 257 nm. These excitation bands corresponded to the transitions from 4f2 ground states (3HJ and 3FJ) to 5d excited states of Pr3+ split by the ligand-field interaction and the spin-orbit coupling. Upon UV excitation at 233 nm, the characteristic Pr3+ 4f15d1→4f2 emission bands were observed at 285 and 312 nm. The scintillation spectrum shows two emission bands peaking at 285 and 312 nm, which is consistent with the photoluminescence, and can thus be assigned to the transitions between the 5d1 excited state and 4f2 ground states owing to the Pr3+. The fast scintillation decay time constants were estimated to be approximately 11.7 ns (53%) and 72 ns (47%). The scintillation light yield reached 5900 ph/MeV.