Effect of the X-ray dose on the luminescence properties of Ce:LYSO and co-doped Ca,Ce:LYSO single crystals for scintillation applications

Mono-doped Ce:LYSO (Lu1.80Y0.2SiO5:Ce) and co-doped Ca,Ce:LYSO and Mg,Ce:LYSO single crystals were prepared by the Czochralski technique. Effects of the X-ray irradiation on the emission spectra and on the light yield are reported. A decrease of the longest wavelength emission (at about 500 nm) and a light yield increase are observed after 1 h under X-ray irradiation. As electron paramagnetic resonance (EPR) evidenced no change in the two cerium sites occupancy along with the irradiation time a mechanism based on the evolution of the oxygen vacancies as neighbors of Ce3+ ions is proposed.