新型碱金属稀土卤化物闪烁晶体M2LaX5的合成、生长及性能研究

Alkali metal rare earth halide is a kind of scintillation crystal material with high light yield, high energy resolution and time resolution. However, most of these crystals have strong water absorption and hydrolysis, which greatly increase the cost of preparation and use..This project uses M2LaX5 as the main research object, and studies their synthesis and dehydration in two halogenated alkyl imidazole ionic liquids [Cnmim]X, and explore a new method of preparation of high purity anhydrous rare earth halide materials in large scale and low cost; Through the transformation of alkali metal and halogen, the M2LaX5 crystal compounds were synthesized, and were grown by the Bridgman method; The effects of different alkali metals and halogen elements on the water absorption and hydrolysis of crystal were analyzed. The energy absorption, transfer and radiative transition rule has been studied by the fluorescence spectra of the crystals determined by using various sources. The radiation level and the characteristics of the scintillation crystals have been analyzed with different alkali metals and halogen elements, and summarized the crystal performance and luminescence mechanism..Through the objective of the research, the aim is to obtain a kind of rare earth halide scintillation crystal material with good water absorption and hydrolysis performance, simple raw material and crystal growth process, excellent scintillation performance.

碱金属稀土卤化物是一类光产额高、能量分辨率和时间分辨率好的闪烁晶体材料。但这类晶体大多具有很强的吸水性和水解性，使得其制备和使用成本大大增加，阻碍了它们的使用。. 本项目以M2LaX5为主要研究对象，研究它们在卤化二烷基咪唑类离子液体[Cnmim]X中的合成和脱水，探索出一种新的高纯无水稀土卤化物原料的大批量、低成本的制备方法；通过碱金属、卤素的变换，合成出不同的M2LaX5晶体化合物，利用坩埚下降法生长出大尺寸M2LaX5:Ce晶体，分析不同碱金属和卤元素对晶体的吸水、水解特性的影响；利用多种辐射源激发，测定晶体的荧光光谱，研究其能量吸收、传递和辐射跃迁规律，分析不同碱金属和卤元素对晶体的辐射能级和闪烁特性的影响，总结晶体的闪烁性能和发光机理。通过本项目的实施，旨在获得一种吸水和水解性能较好、原料处理和晶体生长工艺简单、闪烁性能优良的稀土卤化物闪烁晶体材料。

碱金属稀土卤化物是一类光产额高、能量分辨率和时间分辨率好的闪烁晶体材料。但这类晶体大多具有很强的吸水性和水解性，使得其制备和使用成本大大增加，阻碍了它们的使用。本项目以碱金属稀土卤化物为主要研究对象，研究它们在卤化二烷基咪唑类离子液体[Cnmim]X中的合成和脱水，探索出了一种新的高纯无水稀土卤化物原料的除水方法；开展了二元碱金属稀土卤化物的固相合成及相关物理化学性能表征，分析不同碱金属和卤元素对晶体的潮解、水解性质的影响，利用坩埚下降法生长出物化和闪烁性能均较好的 M2LaX5 晶体6 种、MY2Cl7 (M=Cs、Rb)晶体2种、Cs2MLaX6(M=Na、K，X = Cl, Br)晶体4种，CuI晶体1种；对晶体进行X射线激发发射光谱、光致发光光谱、脉冲高度谱、γ射线衰减能谱、透过率等测试，分析不同碱金属和卤元素对晶体的辐射能级和闪烁特性的影响，总结晶体中各光学活性中心之间的能量传递和转移规律及发光机理。研究期间共发表相关论文15篇，专利4项，培养研究生10名。引进青年教师1名，晋升教授1名。通过本项目的研究表明碱金属稀土卤化物是一类能量分辨率和时间分辨率好、有潜在应用价值的一类闪烁晶体材料，下一步可继续优化晶体生长的工艺，生长出达到应用价值的闪烁晶体。