Modern applications of scintillator materials demand cutting-edge performances and require often a response speed in the nanosecond time scale. Slow light emission causing an "afterglow" is, therefore, of considerable concern in the development of fast scintillators. The mechanism of afterglow emission in mixed Ce-doped oxyorthosilicate scintillators is investigated by means of time-resolved scintillation, thermally stimulated luminescence (TSL), and radio-luminescence measurements. Various Ce-doped Lu2xGd2-2xSiO5 oxyorthosilicate crystals (with x ranging from 0 to1) and Lu1.8Y0.2SiO5 grown by the Czochralski technique are considered. The detailed TSL analysis reveals that thermally assisted tunneling recombination of electrons trapped by oxygen vacancies with holes trapped by Ce luminescence centers occurs for all compositions. The reduction of the afterglow intensity by adding gadolinium or yttrium into the host is accompanied by a lowering of the traps concentration, as deduced by the TSL intensity. Such lowering of the oxygen vacancy concentrations is found to be correlated with the decrease of the melting temperature induced by gadolinium or yttrium content increase, which governs the oxygen vapor pressure. The occurrence of a similar mechanism also in other scintillators and its influence on carrier trapping is discussed.

Sidletskiy, O., Vedda, A., Fasoli, M., Neicheva, S., Gektin, A. (2015). Crystal Composition and Afterglow in Mixed Silicates: The Role of Melting Temperature. PHYSICAL REVIEW APPLIED, 4(2) [10.1103/PhysRevApplied.4.024009].

Crystal Composition and Afterglow in Mixed Silicates: The Role of Melting Temperature

VEDDA, ANNA GRAZIELLA
;
FASOLI, MAURO;
2015

Abstract

Modern applications of scintillator materials demand cutting-edge performances and require often a response speed in the nanosecond time scale. Slow light emission causing an "afterglow" is, therefore, of considerable concern in the development of fast scintillators. The mechanism of afterglow emission in mixed Ce-doped oxyorthosilicate scintillators is investigated by means of time-resolved scintillation, thermally stimulated luminescence (TSL), and radio-luminescence measurements. Various Ce-doped Lu2xGd2-2xSiO5 oxyorthosilicate crystals (with x ranging from 0 to1) and Lu1.8Y0.2SiO5 grown by the Czochralski technique are considered. The detailed TSL analysis reveals that thermally assisted tunneling recombination of electrons trapped by oxygen vacancies with holes trapped by Ce luminescence centers occurs for all compositions. The reduction of the afterglow intensity by adding gadolinium or yttrium into the host is accompanied by a lowering of the traps concentration, as deduced by the TSL intensity. Such lowering of the oxygen vacancy concentrations is found to be correlated with the decrease of the melting temperature induced by gadolinium or yttrium content increase, which governs the oxygen vapor pressure. The occurrence of a similar mechanism also in other scintillators and its influence on carrier trapping is discussed.
Articolo in rivista - Articolo scientifico
Scintillation Crystals; Thermoluminescence; Luminescence; Growth
English
Sidletskiy, O., Vedda, A., Fasoli, M., Neicheva, S., Gektin, A. (2015). Crystal Composition and Afterglow in Mixed Silicates: The Role of Melting Temperature. PHYSICAL REVIEW APPLIED, 4(2) [10.1103/PhysRevApplied.4.024009].
Sidletskiy, O; Vedda, A; Fasoli, M; Neicheva, S; Gektin, A
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/111721
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