辐射光致发光剂量计玻璃的制备与性能

摘要

采用传统的熔融冷却法制得5种不同Li/Na原子比(7∶0、5∶2、1∶1、2∶5、0∶7)的辐射光致发光剂量计玻璃,研究结果揭示了玻璃性能随玻璃组成的变化规律.混合碱作用下玻璃的化学稳定性在Li/Na原子比为5∶2时为最佳,本底剂量则在Li/Na原子比为2∶5时为最差.用钠离子取代锂离子后,钠离子半径大于锂离子半径(rNa+＞rLi+),Na-O键较Li-O键弱,使得玻璃的紫外截止边红移.玻璃中钠离子含量增加使分子量增大,密度随之增大.在337 nm紫外光激发下,荧光强度随玻璃中钠离子含量的增加而增强.电子顺磁共振实验(EPR)表明,随着玻璃中钠离子含量的增加,荧光能增大时间变短.研究结果为在玻璃剂量计实际应用中选择合适的玻璃组成提供依据.%Phosphate radio-photoluminescence dosimeter glasses with five different molar ratios of Li/Na (7 : 0, 5: 2, 1: 1, 2: 5, 0: 7) were prepared by conventional melt-quenching method. The effects of mixed alkali oxides on glass chemical stability and the predose of dosimeter were investigated. The best chemical stability was achieved at Li/Na molar ratio of 5 : 2. However, the dosimeter has the maximal predose when the Li/Na molar ratio is 2 : 5. Because of ionic radius rNa+ >rLi+ and chemical bond Na-O< Li-O, the cut-off wavelength is red-shifted when Li2O is replaced by Na2O. The glass density increases with the increment of Na2O. Under 337 nm UV light excitation, the fluorescence intensity increases with the increment of Na2O. Electron paramagnetic resonance test indicates that the build-up time decreases with the increment of Na2O. For the application of glass dosimeter, the suitable glass composition can be chosen according to the results.