Investigation of luminescence mechanism in La_0.2Y_1.8O₃ scintillator

La_0.2Y_1.8O₃ is a new and promising scintillator which is based on the host material without doping. Here the time gated X-ray excited optical luminescence is measured by using the excitation energy below, above and at the La L₃-edge. A relatively slow and broad emission with peak at 415 nm has been observed as the dominant emission. Also, a weak emission at 360 nm is observed at the fast window, associated with the recombination of trapped excitons in Y₂O₃ host. The observations show that the broad emission at 415 nm is most likely due to the recombination of trapped excitons associated with the La³⁺ doping into Y₂O₃ sites.