Processing of Transparent Polycrystalline AlON:Ce 3+ Scintillators

A new polycrystalline ceramic scintillator is reported for potential use in radiation detection and medical imaging applications. The goal was to develop cerium‐activated aluminum oxynitride (AlON:Ce 3+ ) ceramics, which can be produced using ceramic processes in comparison to the high‐cost, low‐yield single‐crystal growth technique. A phase pure AlON:Ce 3+ powder with cubic symmetry was successfully synthesized at high temperature under a reducing atmosphere to convert Ce 4+ to Ce 3+ in the solid solution. Two different activator concentrations (0.5 and 1.0 mol%) were explored. Fully dense and transparent AlON:Ce 3+ ceramics were produced by a liquid‐phase‐assisted pressureless sintering. The crystal field splitting around the Ce 3+ activator in the AlON was comparable to the splitting induced by Br − and the Cl − ligands, which produced an emission spectrum perfectly matching the maximum quantum efficiency range of the photomultiplier tube for radiation detection. Both optical excitation and radiation ionizations in AlON:Ce 3+ were demonstrated. Challenges and mechanisms related to the radioluminescence efficiency are discussed.