Short-term fading studies on optically stimulated luminescence in LiMgPO4:Er

Abstract

The main drawback of LiMgPO4 is high fading. In order to improve the time stability of the optically stimulated luminescence (OSL) signal of LiMgPO4 after irradiation, five preparation processes had been adopted to prepare five kinds of LiMgPO4:Er phosphor. The structure of the prepared samples was analyzed by X-ray diffraction. The OSL decay curves, thermoluminescence (TL) glow curves, OSL sensitivity, minimum detectable dose (MDD) and the fading properties after irradiation for the five kinds of LiMgPO4:Er phosphors were investigated. Considering minimizing fading 24 h after irradiation, the preparation process for samples heated at 900 °C for 10 h is optimal. The OSL fading of LiMgPO4 phosphor is improved significantly by changing the preparation processes. The less than 5% loss of the OSL signal was measured after 24 h of the irradiation for samples heated at 900 °C for 10 h when the integration time is more than 0.5 s, and the sensitivity by taking the total area under the OSL curve of this samples is about half that of TLD-500k. There is a loss of less than or equal to 5% of the OSL signal for samples heated at 900 °C for 10 h when the integration time is greater than or equal to 20 s within 30 days after irradiation. LiMgPO4:Er samples heated at 900 °C for 10 h is the LiMgPO4 phosphor with the lowest fading so far. It is possible to prepare a LiMgPO4 phosphor with a low fading after irradiation and a moderate sensitivity by further investigating the preparation processes.