采用自蔓延燃烧法制备了不同Eu3+掺杂浓度的CaGd1-xAlO4∶xEu3+(CGA∶xEu3+)X射线荧光粉材料.当Eu3+掺杂浓度在0~0.150范围时, Eu3+取代了基质中处于无中心反演对称的格位, 使CGA∶xEu3+样品呈现为单一相, 并可观察到红光发射.当x=0.100时, 红光发射强度达到最大.随着Eu3+离子浓度增加, Eu3+离子之间的距离减小, 增大了Eu3+→Eu3+→猝灭中心的能量传递几率, 出现了发光猝灭现象.实验发现, 当Eu3+掺杂浓度为0.003时, 光激励发光强度最大.对CGA∶0.003Eu3+样品进行氮气气氛热处理后, CGA中的OH-离子基团减少, 红光发射的发光强度增强.热释曲线表明CGA∶0.003Eu3+样品中存在两种类型的陷阱, 其陷阱深度分别为0.79 eV和0.93 eV.经氮气热处理后的CGA∶0.003Eu3+样品, 较深陷阱数量显著增多, 光激励发光强度增强, 光存储性能显著提高.随着X射线辐照时间的增加, X射线吸收剂量在0~11.8 Gy范围内大致呈线性增加的趋势.当X射线吸收剂量为1.2 Gy时, 以在氮气气氛下热处理CGA∶0.003Eu3+圆片为成像板, 得到了较高质量X射线红色成像.实验结果表明, Eu3+掺杂的CGA X射线荧光粉材料在以CCD为光探测器的计算机X射线医学成像技术中有潜在的应用前景.

CaGd1-xAlO4: xEu3+(CGA∶xEu3+) X-ray storage phosphors with different doping concentrations of Eu3+ were synthesized by a combustion method．In the doping concentrations range of 0~0.150, single phased CGA∶xEu3+ powders are acquired and Eu3+ occupying the sites without symmetric inversion center leads to strong red emissions. For the CGA∶0.100Eu3+ phosphor, the strongest red emission intensity can be observed. As the concentration of Eu3+ ions increases, the distance between Eu3+ ions decreases, increasing the energy transfer probability of Eu3+→Eu3+→annihilation center, and luminescence quenching occurs. When the Eu3+ doping concentration is 0.003, the strongest intensity of the photo-stimulable luminescence can be obtained. For the annealed CGA∶0.003Eu3+ phosphor in nitrogen ambient, the number of OH- groups in CGA is decreased and the red emission intensity is enhanced compared to the unannealed sample. The thermoluminescence analysis shows that there exist two kinds of traps in the CGA∶0.003Eu3+phosphors and the trap depths are 0.79 and 0.93 eV, respectively. In particular, the annealing in nitrogen leads to the increased number of traps, the enhanced photo-stimulable luminescence intensity and the improved storage properties. The nearly linear relationship between the X-ray absorbed dose and the X-ray irradiation time can be found in the range of 0~11.8 Gy. When the X-ray absorbed dose is 1.2 Gy, an imaging plate made of CGA∶0.003Eu3+ heat-treated under a nitrogen atmosphere obtains high-quality X-ray red imaging. The experimental results show that Eu3+ doped CGA X-ray phosphor materials have potential applications in computer X-ray medical imaging with CCD as photodetector