Characterization of LuAG:Ce,Ca and LYSO:Ce,Ca Scintillators for Multiple Photon Emission

The energy resolution of scintillator detectors is limited by their light yield. Multiple photon generation via reexcitation of the activator ions within a scintillator is one theoretical pathway for amplifying the light output. Lu2(1-x)Y2xSiO5 and Lu3Al5O12 (LuAG) co-doped with Ce and Ca are candidate materials for verifying this mechanism. The emission and excitation spectra of Ce and Ce,Ca co-doped samples of both LuAG and LYSO were collected using spectrofluorophotometry to evaluate the impact of Ca on the Ce activator ions’ valence states. These measurements indicate Ca co-doping converts the Ce3+ to Ce4+ in both materials. A dual-beam optical and X-ray experiment was designed to compare the response signal amplitude of the single- and dual-beam excitation of these materials using a chopper wheel and a lock-in amplifier. Initial calibration of the design shows successful readout of optical excitation at various LED (light emitting diode) currents.