Processing of Transparent Polycrystalline AlON:Ce³⁺ Scintillators

Abstract

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.

Transparent polycrystalline Gd2Hf2O7 ceramics

“…In‐line transmission with wavelength from 200 to 3000 nm was measured using a Varian Instruments Cary 5000 UV‐Vis‐NIR Double‐Grating Double‐Beam Spectrophotometer . Variable Angle Spectroscopic Ellipsometry (VASE ® ) was used to characterize the refractive index and extinction coefficient (n&k values) of the Gd 2 Hf 2 O 7 over a wide spectral range.…”

“…Gd 2 Hf 2 O 7 has a cubic structure as well as high Z eff , making it a potential host lattice for scintillators . Biswas et al studied the low temperature properties of Gd 2 Hf 2 O 7 using crystal‐field theory.…”

“…Gd 2 Hf 2 O 7 has a cubic structure as well as high Z eff , making it a potential host lattice for scintillators. [3][4][5][6][7] Biswas et al 8 studied the low temperature properties of Gd 2 Hf 2 O 7 using crystal-field theory. Gd 2 Hf 2 O 7 powders were synthesized by Sevastyanov et al 9 Li et al 10 investigated the radiation damage of Gd 2 Hf 2 O 7 .…”

Planetary ball‐milling of AlON powder for highly transparent ceramics

“…Synthesis methods include solid‐state reaction method, aluminothermic reduction nitridation method, and carbothermal nitridation method (CRN) . The synthetic AlON powder can be sintered into ceramics by hot‐pressing method, hot isostatic pressing method, and pressurless sintering method . Particularly, combing carbothermal nitridation method with pressurless sintering method is preferred due to its low cost, which enables potential commercialization with large‐scale production for highly transparent AlON ceramics.…”

Variation of Structure and Photoluminescence Properties of Ce3+ Doped MgAlON Transparent Ceramics with Different Doping Content

“…One is the optical transparency. Relatively high transparency always means large flux of incident and transmission light, which is in favor of the energy usage ratio to the materials [8]. Another factor is the optical energy conversion efficiency of the appropriate volume activator ions.…”