Scintillation Properties of Rb₂Cu(Cl,Br)₃ Crystals

(RbCu)-Cu-2(Cl,Br)(3) crystals were synthesized by the slow cooling method and their photoluminescence (PL) and scintillation properties were evaluated. PL emission peaks at 390 nm due to the recombination of excitons were observed, and the PL quantum yields of Rb2CuCl3, Rb2Cu(Cl-0.5,Br-0.5)(3), and Rb2CuBr3 were 91.2, 95.3, and 96.3%, respectively. PL decay curves were approximated using a single exponential function model, and the obtained decay time constants were 15-66 mu s. Under X-ray irradiation, the scintillation emission peaks of the samples were observed at 390 nm, and the decay times were 11-63 mu s. The afterglow levels at 20 ms after X-ray irradiation were calculated to be 30-450 ppm. Rb2CuCl3 showed the highest scintillation light yield of 11000 photons/MeV among the samples when calculated from the pulse height spectra of Cs-137 gamma-rays (662 keV).