新型氧化物闪烁陶瓷的制备与性能优化

发布时间：2018-06-08 04:31

本文选题：倍半氧化物闪烁陶瓷 + X射线荧光　；参考：《上海应用技术大学》2017年硕士论文

【摘要】：闪烁体是一种能将入射在其上的高能射线或粒子转换为紫外或可见光的功能材料。随着医疗成像(CT)、安全监测设备的发展以及高能物理中大型快速电磁量能器的建立和更新换代,对闪烁体提出了高光输出、快衰减、高耐辐射以及低成本等越来越苛刻的要求。Eu3+离子掺杂的倍半氧化物陶瓷具有较高的光输出而备受关注,上世纪80年代美国GE公司已经制备出性能优良的(Y,Gd)2O3:Eu闪烁陶瓷,并成功应用于医学X-CT上,且同结构Lu2O3具有较大的密度和较高的有效原子序数,对X射线具有更强的吸收能力,Gd3+的共掺可以提高Y2O3:Eu和Lu2O3:Eu的X射线荧光效率。本课题在Y2O3:Eu陶瓷的研究基础上,进一步研究了(Y,Gd)2O3:Eu和(Lu,Gd)2O3:Eu闪烁陶瓷的制备工艺及性能优化。首先研究了不同温度退火对HIP处理的Y2O3:Eu闪烁陶瓷样品光学性能和发光性能的影响。退火后样品的发光效率提高,但是在较高温度退火下,陶瓷样品光学质量在短波范围(200-500nm)内下降,与陶瓷材料内部被压缩的微气孔重新扩张有关,造成光散射增加,光学质量下降。同时研究了 Gd3+共掺(Y,Gd)2O3:Eu陶瓷样品的发光与闪烁性能,发现存在Gd3+到Eu3+离子的能量传递,可以提高Y2O3:Eu闪烁陶瓷的发光效率,同时提高了材料的密度,增强对X射线的吸收能力,且Gd3+的共掺促进了 Eu3+离子的5D0→7F0电子跃迁,降低了荧光寿命。从热释光信号也可以看出Gd3+的共掺使得深能级陷阱变浅以及缺陷浓度降低。同时研究了 Gd3+共掺Lu2O3:Eu闪烁陶瓷,通过组分设计制备出(Lu1-xGdx)2O3:Eu(x=0,0.1, 0.3, 0.5, 0.7, 0.9)系列未添加烧结助剂的闪烁陶瓷。当Gd3+的含量小于等于50%时,Lu2O3和Gd2O3能够完全固溶,形成立方相(Lu,Gd)2O3:Eu固溶体陶瓷,且材料的禁带宽度随着Gd3+的含量的增加不断减小,理论上禁带宽度减小能够提高材料的光输出,(Lu,Gd)2O3:Eu陶瓷样品光致发光和X射线辐照的稳态发光效率随着Gd3+量的增加不断增强。但当Gd3+含量超过70%,(Lu,Gd)2O3:Eu闪烁陶瓷由立方相变为单斜相甚至六方相,单斜相中Eu3+离子的发光较弱,且峰形与Eu3+离子在典型的单斜相的Gd2O3相一致。此外还探究了 Y2O3:Eu和(Lu,Gd)2O3:Eu闪烁陶瓷的抗辐照损伤性能,发现两种材料在X射线辐照下,均在在300-700nm范围内诱导出现了新的吸收带,可能与材料内部杂质(Yb3+)以及Eu3+/e-缺陷态等其他因素有关。(Lu,Gd)2O3:Eu系列陶瓷样品随着下X射线续辐照时间的延长,样品稳态发光强度逐渐下降,与未掺杂Gd3+的Lu2O3:Eu相比,(Lu,Gd)2O3:Eu陶瓷样品发光强度随着时间的延长降低缓慢,Gd3+的共掺有利于样品抗辐照性能的提升。
[Abstract]:Scintillators are functional materials that can convert high-energy rays or particles incident on them into ultraviolet or visible light. With the development of medical imaging, the development of safety monitoring equipment and the establishment and renewal of large and fast electromagnetic calorimeter in high energy physics, the high light output and fast attenuation of scintillator are proposed. The high radiation resistance and low cost are becoming more and more demanding. Eu3 ion doped double oxide ceramics have attracted much attention because of their high light output. In the 1980s, GE Corporation of the United States has produced excellent scintillation ceramics, such as YYN GdN 2O 3: EU. The X-ray fluorescence efficiency of Y _ 2O _ 3: EU and Lu _ 2O _ 3: EU can be improved by co-doping of Gd _ 3 and Y _ 2O _ 3: EU with higher density and higher effective atomic number. Based on the study of Y _ 2O _ 3: EU ceramics, the preparation process and performance optimization of YTO _ 3 / O _ 3: EU scintillator ceramics were studied. The effects of annealing temperature on the optical and luminescent properties of Y _ 2O _ 3: EU scintillator ceramics treated with hip were studied. After annealing, the luminescence efficiency of the samples was improved, but the optical quality of the samples decreased in the short wave range of 200-500 nm at high temperature, which was related to the reexpansion of the compressed micropores in the ceramics, which resulted in the increase of light scattering. The optical quality drops. The luminescence and scintillation properties of Gd3 co-doped GdC2O3: EU ceramics were also studied. It was found that the energy transfer from Gd3 to EU3 ions could improve the luminescence efficiency of Y2O3: EU scintillation ceramics, at the same time, the density of the materials was increased and the absorption capacity of X-ray was enhanced. Moreover, the co-doping of Gd3 promotes the 5D0 ~ 7F0 electron transition of EU _ 3 ion and reduces the fluorescence lifetime. It can also be seen from the thermoluminescence signal that the co-doping of Gd3 makes the deep level trap shallower and the defect concentration decrease. At the same time, the scintillation ceramics of Gd3 co-doped Lu2O3: EU have been studied. The scintillation ceramics without sintering aids have been prepared by the component design of Lu1-xGdxT2O3: EuxOXO _ 1, 0.3,0.3,0.5,0.7and 0.9). When the content of Gd3 is less than or equal to 50%, Lu2O3 and Gd2O3 can completely solute and form the cubic phase Lu-GdC2O3: EU solid solution ceramics. The band gap of the material decreases with the increase of Gd3 content. Theoretically, the photoluminescence and the steady-state luminescence efficiency of X-ray irradiation can be increased with the increase of Gd3 content. However, when the Gd3 content exceeds 70%, the phase transition from cubic phase to monoclinic phase or even hexagonal phase is obtained. The luminescence of EU3 ion in monoclinic phase is weak, and the peak shape is consistent with that of EU 3 ion in typical monoclinic phase Gd _ 2O _ 3. In addition, the radiation damage resistance of Y _ 2O _ 3: EU and Lun Gdttrio _ 2O _ 3: EU scintillators was investigated. It was found that new absorption bands appeared in the range of 300-700nm for both materials under X-ray irradiation. It may be related to the impurity Yb3) and other factors such as EU 3 / e- defect state. The steady-state luminescence intensity of the samples decreases with the prolongation of X-ray irradiation time. Compared with undoped Lu2O3: EU, the luminescence intensity of Lu2O3: EU ceramics decreases slowly with the increase of time, and the co-doping of Gd3 can improve the radiation resistance of the samples.
【学位授予单位】：上海应用技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ174.1

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