Influence of yttrium Content on the Ce1 and Ce2 Luminescence Characteristics in $({\rm Lu}_{1-{\rm x}}{\rm Y}_{\rm x})_{2}{\rm SiO}_{5}:{\rm Ce}$ Single Crystals

We investigate the luminescence and scintillation characteristics of highly efficient cerium-doped scintillators, lutetium-(yttrium) orthosilicate (Lu_2(1-x)Y_2xSiO₅:Ce, x=0-1). The radioluminescence, photoluminescence excitation (PLE) and emission (PL) spectra of the Ce1, Ce2 centres as well as the decay curves and their temperature dependences are measured in the 80-500 K range. Light yield values are provided as well. The influence of yttrium concentration on the Ce1, Ce2 luminescence characteristics is demonstrated. With increasing yttrium content the onset of the Ce1 and Ce2 decay time decrease as well as the Ce1, Ce2 delayed recombination integrals increase shift to higher temperatures. The 5d₁ thermally induced excited-state ionization of both Ce1 and Ce2 centres is confirmed and studied by purely optical methods.