Scintillation Properties of Ba₃RE(PO₄)₃ Single Crystals (RE = Y, La, Lu)

Eulytite-type Ba₃RE(PO₄)₃ (RE = Y, La, and Lu) single crystals were synthesized by the floating zone method, and their scintillation properties were investigated. The powder X-ray diffraction measurement revealed that the single phase of Ba₃RE(PO₄)₃ samples were successfully synthesized. The samples exhibited a luminescence peak due to self-trapped exciton at around 400 nm under vacuum ultraviolet and X-ray irradiation. The X-ray-induced scintillation decay time constants of the samples were several microseconds at room temperature. In the ²⁴¹Am α-ray irradiated pulse height spectra, all the samples showed a clear full energy peak, and the absolute light yields of the Ba₃Y(PO₄)₃, Ba₃La(PO₄)₃, and Ba₃Lu(PO₄)₃ single crystals were estimated to be 960, 1160, and 1220 ph/5.5 MeV-α, with a typical error of ±10%, respectively. The scintillation light yields of the Ba₃RE(PO₄)₃ have been quantitatively clarified for the first time.