Compositional regulation of multi-component GYGAG:Ce scintillation ceramics:Self-sintering-aid effect and afterglow suppression

(Gd,Y,Ce)_(3)(Y_(x)Ga_(1−x))_(2)GaAl_(2)O_(12)(GYGAG:Ce)scintillation ceramics with different Y excess,where x=0.005−0.08,were fabricated by the solid-state reaction method.The effects of stoichiometry on the phase composition,optical quality,and microstructure of GYGAG:Ce ceramics were analyzed.GYGAG:Ce ceramics have a pure garnet phase and obtain good in-line transmittance when x<0.04,while more Y excess leads to the creation of the secondary phase.The change of x value influences the sintering behavior of the GYGAG:Ce ceramics:The excess of Y works as the self-sintering aid and significantly reduces the sintering temperature of ceramics.When x=0.01–0.04,the X-ray excited luminescence(XEL)spectra and light yields of GYGAG:Ce ceramics are similar.The fast scintillation decay time and afterglow intensity of GYGAG:Ce ceramics show a slight decrease with increasing x value.Finally,additional 50–500 ppm MgO and 100–500 ppm CaO were introduced to the GYGAG:Ce ceramic with x=0.04,and both were found to significantly increase the fast scintillation component and reduce the afterglow intensity by two orders of magnitude to 0.01%after X-ray cut-off.

Development and prospects of garnet ceramic scintillators:A review

Garnet ceramic scintillators are a class of inorganic scintillation materials with excellent overall performance.The flexibility of cation substitution in different lattice positions leads to tunable and versatile properties and a wide range of applications.This paper starts with an overview of the development history of the inorganic scintillation materials,followed by a description of major preparation methods and characterization of garnet scintillation ceramics.Great progress obtained in recent years consisting in applying the band-gap and defect engineering strategies to the garnet scintillation ceramics is reviewed.Finally,the respective problems in the preparation and performance of multicomponent garnet single crystals and ceramics and the effective solutions are discussed.The garnet scintillation ceramics with the highest application potential are summarized,and the future development directions are proposed.

Exciton-harvesting enabled efficient charged particle detection in zero-dimensional halides

Materials for radiation detection are critically important and urgently demanded in diverse fields,starting from fundamental scientific research to medical diagnostics,homeland security,and environmental monitoring.Lowdimensional halides(LDHs)exhibiting efficient self-trapped exciton(STE)emission with high photoluminescence quantum yield(PLQY)have recently shown a great potential as scintillators.However,an overlooked issue of excitonexciton interaction in LDHs under ionizing radiation hinders the broadening of its radiation detection applications.Here,we demonstrate an exceptional enhancement of exciton-harvesting efficiency in zero-dimensional(0D)Cs_(3)Cu_(2)I_(5):Tl halide single crystals by forming strongly localized Tl-bound excitons.Because of the suppression of nonradiative exciton-exciton interaction,an excellentα/βpulse-shape-discrimination(PSD)figure-of-merit(FoM)factor of 2.64,a superior rejection ratio of 10^(−9),and a high scintillation yield of 26000 photons MeV−1 under 5.49 MeVα-ray are achieved in Cs_(3)Cu_(2)I_(5):Tl single crystals,outperforming the commercial ZnS:Ag/PVT composites for charged particle detection applications.Furthermore,a radiation detector prototype based on Cs_(3)Cu_(2)I_(5):Tl single crystal demonstrates the capability of identifying radioactive 220Rn gas for environmental radiation monitoring applications.We believe that the exciton-harvesting strategy proposed here can greatly boost the applications of LDHs materials.