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Author(s)
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Liu, Shuping (Shanghai Inst. Ceramics ; Beijing, GUCAS) ; Feng, Xiqi (Shanghai Inst. Ceramics) ; Mares, Jiri A (ASCR, Prague) ; Babin, V (ASCR, Prague) ; Nikl, Martin (ASCR, Prague) ; Beitlerova, Alena (ASCR, Prague) ; Shi, Yun (Shanghai Inst. Ceramics) ; Zeng, Yanping (Shanghai Inst. Ceramics) ; Pan, Yubai (Shanghai Inst. Ceramics) ; D’Ambrosio, Carmelo (CERN) ; Huang, Yihua (Shanghai Inst. Ceramics) |
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Abstract
| Non-stoichiometric $Lu_{3+x}Al_{5}O_{12}:Ce$ ($Lu_{3+x}$AG:Ce, x=1, 2, 3 and 4 %) ceramics were fabricated by solid state reaction method and further optimized by an air-annealing process. Absorption, luminescence spectra and scintillation characteristics such as light yield, scintillation decay times, energy resolution, proportionality and afterglow were measured and compared with those of the latest LuAG:Ce single crystal and stoichiometric LuAG:Ce,Mg ceramic samples. Thanks to the elimination of oxygen vacancies produced in the vacuum sintering process, air-annealing treatment led to a significant decrease of afterglow and a remarkable enhancement of radioluminescence intensity and light yield. The highest light yield was found in annealed 1% Lu3+ rich Lu3+1%AG:Ce ceramic, reaching 14,760 ph/MeV (1 μs shaping time) and 22,400 ph/MeV (10 μs shaping time). Scintillation decays of $(Lu_{3+x}$AG:Ce ceramics consist of both fast (decay time 65–73 ns) and slow (decay time 740–1116 ns) decay components where the relative intensity of the latter is higher ( 58%). A decreasing trend in scintillation efficiency was observed with increasing excess of Lu (with higher x values) in the samples. This can be explained by the existence of various electron traps due to LuAl antisite defect and structure disorder at the gain boundaries and interfaces. |