Systematic comparison of saturation effects and afterglow properties of Sr4Al14O25 Eu, Dy phosphor excited by alpha and beta ionizing sources and UV light /

Abstract This study reports on the radioactive- and photo-charging effects related afterglow properties of the long-afterglow Sr4Al14O25:Eu, Dy phosphor (SAED). Saturation and oversaturation behavior, trapping and de-trapping sequences, decay profiles and resistivity of SAED to alpha, beta and UV ex...

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Bibliographic Details
Main Authors: Havasi Viktor
Tátrai Dávid
Szabó Gábor
Sipos György
Kónya Zoltán
Kukovecz Ákos
Format: Article
Published: 2017
Series:JOURNAL OF MOLECULAR STRUCTURE 1140
doi:10.1016/j.molstruc.2017.01.001

mtmt:3174227
Online Access:http://publicatio.bibl.u-szeged.hu/12420
Description
Summary:Abstract This study reports on the radioactive- and photo-charging effects related afterglow properties of the long-afterglow Sr4Al14O25:Eu, Dy phosphor (SAED). Saturation and oversaturation behavior, trapping and de-trapping sequences, decay profiles and resistivity of SAED to alpha, beta and UV excitations are detailed. Thermoluminescence and afterglow measurements were performed on SAED subjected to different irradiation dose/time. In order to determine the saturation point of SAED, phosphors were charged by 0.5–800 Gy dose using radioactive alpha and beta sources and for 0.02–900 min by near UV light. By radioactive excitations only a saturation tendency was observed, whereas clear indication of oversaturation was found for photo-charging. Different saturation tendencies were also observed as a function of average SAED particle size due to the different penetration depth and efficiency of the excitation radiations. A uniform de-trapping sequence, but an opposite trapping sequence was found for ionizing radiation and for UV charging due to secondary excitation effects of high-energy irradiation. After the saturation point, a slight reduction of charge carrier concentration and PL intensity were observed. This was evidenced by the shifting dominant components of the modeled afterglow and TL curves. Repeated charging by ionizing radiation does not effected the afterglow properties of SAED adversely. On the other hand, thermal exposure up to 350 °C reduced photoluminescence intensity even in inert atmosphere.
Physical Description:89-98
ISSN:0022-2860