Intrinsic luminescence and luminescence of inadvertent impurities in LuAP and LuYAP crystals

To clarify the potential of LuAP:Ce and LuYAP:Ce scintillators of new generation the mechanisms of the energy transfer from the matrix to the cerium ions and competing relaxation channels were investigated using VUV luminescence spectroscopy for the crystals provided by different producers using different growth techniques. With temperature being one of the ways to control the light yield of these crystals, effect of temperature was studied for different excitation energies. Anomalous temperature dependence of the luminescence light yield under VUV excitation was analyzed. New intrinsic luminescence band was observed in all of the crystals and energy transfer from it to cerium ions was demonstrated. New luminescence band in the IR peaking around 750 nm was defected, its origin and effect on the scintillator performance is discussed.