Publications Details

Processing of transparent polycrystalline AlON:Ce³⁺ scintillators

Chen, Ching F.; King, Graham; Tegtmeier, Eric L.

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:Ce³⁺) ceramics, which can be produced using ceramic processes in comparison to the high-cost, low-yield single-crystal growth technique. A phase pure AlON:Ce³⁺ powder with cubic symmetry was successfully synthesized at high temperature under a reducing atmosphere to convert Ce⁴⁺ to Ce³⁺ in the solid solution. We explored two different activator concentrations (0.5 and 1.0 mol%). Fully dense and transparent AlON:Ce³⁺ ceramics were produced by a liquid-phase-assisted pressureless sintering. The crystal field splitting around the Ce³⁺ 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:Ce³⁺ were demonstrated. Lastly, challenges and mechanisms related to the radioluminescence efficiency are discussed.