面向X-CT应用的(Ce, Lu)3(Cr, Al)5O12闪烁陶瓷中过渡金属离子的光谱展宽效应研究

Considering the requirement of X-CT apparatus and its future upgrading, this project is planning to focus on the study of key materials and technologies to couple with the high resolution of Silicon photo electric dioed detectors, the emphasis is on scintillator ceramics of Ce: LuAG having performance of high density, high luninescence efficiency. By codoping the transition metal ions Cr3+ (ionic radius 0.068nm) to the octahedron site in LuAG lattice replacing the Al3+ (ionic radius 0.05nm) to realize the luminescence spectrum design. It is aimed to investigated the first principle method, micro-chip screen method as well as the fabrication technology of high transparent ceramics to study the effect of transition metal ions on spectrum broadening by overlap the Ce3+ emission at 550nm and Cr3 at 730nm. It is expected to contribute to the application of X-CT technology of our country by the study of this project.

针对高性能X-CT的应用需求和未来发展趋势，开展硅光电二极管耦合用关键闪烁材料的设计制备研究，以高密度、发光效率高的Ce：LuAG闪烁透明陶瓷为基础体系，选取与Al3+离子半径（0.05 nm）接近的过渡金属发光离子 Cr3+（0.068 nm）进行八面体格位替代，研究通过第一性原理导带和能级结构的计算，材料制备组分调控，将主发光在550nm的Ce3+发光与主发光在730m的Cr3+的发光叠加，达到发光光谱展宽，并研究高光效发光的组分调控方案，最终材料与硅光二极管探测灵敏区匹配良好，实现可见和近红外闪烁发光的叠加展宽，应用于高性能X-CT机中。

本项目拟针对X-CT 对闪烁材料的具体要求( 按重要性递减顺序) : ( 1) 低余辉( < 1% @ 3ms)；( 2) 高稳定性( 化学、温度、辐射损伤)；(3) 高密度( > 6 g/cm3 )；(4) 发射波长与硅光电二极管读出( 500~1000nm) 匹配良好；(5) 高发光效率( > 15, 000 Pho/MeV ) ；选取具有发光效率高（>20,000 Pho/MeV ），密度高（6.7 g/cm3）特点的Ce:LuAG为基础体系，通过导带和能级结构的设计，材料制备组分调控，获得高光效发光的组分调控方案，最终发展了Cr:LuAG红光闪烁材料，并系统研究了Mg2+，Y3+，Pr3+, Gd3+，Ga3+和复合结构等对闪烁性能的优化作用，获得了主发射波段在706nm处的新型红光材料，实现与硅光二极管300 nm---1000 nm读出区500nm---1000nm区近红外发光匹配良好；并发展复杂组分(CexLu1-x)3(CryAl1-y)5O12闪烁陶瓷的关键制备技术，为实现其在高性能X-CT 中的应用提供了材料基础和实验依据。