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Synthesis of Borates with Various Microstructures and Their Application in Radiation Dosimetry

Author: GaoXiaoFeng
Tutor: ZhangHaiQian
School: Nanjing University of Aeronautics and Astronautics
Course: Radiation protection and environmental protection
Keywords: thermoluminescent lithium borate sintered pellet lithium borate microcrystal calciumborate nanophosphor photoluminescence spectra
CLC: TQ128.5
Type: Master's thesis
Year: 2013
Downloads: 7
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Abstract


These years, borates come to hold an important position in the entire thermoluminescent materialssystem, it is meaningful to explore novel methods for synthesizing the borate thermoluminescentmaterials with various microstructures which can meet the requirements of dosimetry measurementsin different situations. In our work, the borate thermoluminescent materials with differentmicrostructure were synthesized via different methods, and the thermoluminescent properties of thesematerials were studied.The Li2B4O7doped with Cu （LTB:Cu） was synthesized in water bath for the first time, and theanhydrous LTB:Cu pellets was obtained via a high-temperature treatment. In contrast, LTB: Cupellets were also synthesized by traditional method of direct sintering. The LTB:Cu pellets preparedin water bath present more simple glow curve and less decay compared to the LTB:Cu pelletssynthesized by direct sintering. The thermoluminescence mechanism of LTB:Cu was discussed byCGCD （Computerized Glow Curve Deconvolution） and PL（Photoluminescence） measurements, theresults indicated that the sintered LTB: Cu pellets showed linear responses over a large range, withlow decay and good reproducibility. These properties ensure their use in γ-ray measurements.The LTB:Cu microcrystals were obtained via sintering Li3B5O8（OH）2which was synthesized inhydrothermal, and the thermoluminescent properties of the microcrystals were studied for the firsttime. The thermoluminescent glow curve and the PL spectra were measured, and thethermoluminescence mechanism of LTB:Cu microcrystals was discussed. The results indicated thatthe LTB:Cu microcrystals exhibited linear responses over a very wide range （105×103Gy）, and theimpact of the thermoluminescence decay could be reduced by preheating before the measurement. Sowe could conclude that the LTB:Cu microcrystals we had obtained could be used for measurements ofhigh-dose gamma radiations.Calcium borate nanocrystals doped with Ce3+(CaB4O7:Ce3+nanophosphor) were synthesized bythe method of precipitation, and their application in radiation dosimetry was discussed for the fist time.The thermoluminescence mechanism of CaB34O7:Ce+nanophosphor was also discussed by CGCDand PL measurements. The properties of CaB34O7:Ce+nanophosphor, such as the TL response, fadingand reusability, were also studied. The results indicated that CaB4O7:Ce3+nanophosphor we hadobtained could be a good candidate for radiation measurements for its perfect characters of the highsensitivity, linear response over a range of exposure from1100Gy, low fading and excellentreproducibility.

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CLC: > Industrial Technology > Chemical Industry > Non-metallic elements and their inorganic compounds, the chemical industry > Section Ⅲ- non-metallic elements ( boron ) and its inorganic compounds > Oxygenated acids of boron
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