本文選題：倍半氧化物閃爍陶瓷 + X射線熒光　； 參考：《上海應(yīng)用技術(shù)大學(xué)》2017年碩士論文

【摘要】：閃爍體是一種能將入射在其上的高能射線或粒子轉(zhuǎn)換為紫外或可見光的功能材料。隨著醫(yī)療成像(CT)、安全監(jiān)測設(shè)備的發(fā)展以及高能物理中大型快速電磁量能器的建立和更新?lián)Q代,對閃爍體提出了高光輸出、快衰減、高耐輻射以及低成本等越來越苛刻的要求。Eu3+離子摻雜的倍半氧化物陶瓷具有較高的光輸出而備受關(guān)注,上世紀(jì)80年代美國GE公司已經(jīng)制備出性能優(yōu)良的(Y,Gd)2O3:Eu閃爍陶瓷,并成功應(yīng)用于醫(yī)學(xué)X-CT上,且同結(jié)構(gòu)Lu2O3具有較大的密度和較高的有效原子序數(shù),對X射線具有更強(qiáng)的吸收能力,Gd3+的共摻可以提高Y2O3:Eu和Lu2O3:Eu的X射線熒光效率。本課題在Y2O3:Eu陶瓷的研究基礎(chǔ)上,進(jìn)一步研究了(Y,Gd)2O3:Eu和(Lu,Gd)2O3:Eu閃爍陶瓷的制備工藝及性能優(yōu)化。首先研究了不同溫度退火對HIP處理的Y2O3:Eu閃爍陶瓷樣品光學(xué)性能和發(fā)光性能的影響。退火后樣品的發(fā)光效率提高,但是在較高溫度退火下,陶瓷樣品光學(xué)質(zhì)量在短波范圍(200-500nm)內(nèi)下降,與陶瓷材料內(nèi)部被壓縮的微氣孔重新擴(kuò)張有關(guān),造成光散射增加,光學(xué)質(zhì)量下降。同時研究了 Gd3+共摻(Y,Gd)2O3:Eu陶瓷樣品的發(fā)光與閃爍性能,發(fā)現(xiàn)存在Gd3+到Eu3+離子的能量傳遞,可以提高Y2O3:Eu閃爍陶瓷的發(fā)光效率,同時提高了材料的密度,增強(qiáng)對X射線的吸收能力,且Gd3+的共摻促進(jìn)了 Eu3+離子的5D0→7F0電子躍遷,降低了熒光壽命。從熱釋光信號也可以看出Gd3+的共摻使得深能級陷阱變淺以及缺陷濃度降低。同時研究了 Gd3+共摻Lu2O3:Eu閃爍陶瓷,通過組分設(shè)計制備出(Lu1-xGdx)2O3:Eu(x=0,0.1, 0.3, 0.5, 0.7, 0.9)系列未添加燒結(jié)助劑的閃爍陶瓷。當(dāng)Gd3+的含量小于等于50%時,Lu2O3和Gd2O3能夠完全固溶,形成立方相(Lu,Gd)2O3:Eu固溶體陶瓷,且材料的禁帶寬度隨著Gd3+的含量的增加不斷減小,理論上禁帶寬度減小能夠提高材料的光輸出,(Lu,Gd)2O3:Eu陶瓷樣品光致發(fā)光和X射線輻照的穩(wěn)態(tài)發(fā)光效率隨著Gd3+量的增加不斷增強(qiáng)。但當(dāng)Gd3+含量超過70%,(Lu,Gd)2O3:Eu閃爍陶瓷由立方相變?yōu)閱涡毕嗌踔亮较?單斜相中Eu3+離子的發(fā)光較弱,且峰形與Eu3+離子在典型的單斜相的Gd2O3相一致。此外還探究了 Y2O3:Eu和(Lu,Gd)2O3:Eu閃爍陶瓷的抗輻照損傷性能,發(fā)現(xiàn)兩種材料在X射線輻照下,均在在300-700nm范圍內(nèi)誘導(dǎo)出現(xiàn)了新的吸收帶,可能與材料內(nèi)部雜質(zhì)(Yb3+)以及Eu3+/e-缺陷態(tài)等其他因素有關(guān)。(Lu,Gd)2O3:Eu系列陶瓷樣品隨著下X射線續(xù)輻照時間的延長,樣品穩(wěn)態(tài)發(fā)光強(qiáng)度逐漸下降,與未摻雜Gd3+的Lu2O3:Eu相比,(Lu,Gd)2O3:Eu陶瓷樣品發(fā)光強(qiáng)度隨著時間的延長降低緩慢,Gd3+的共摻有利于樣品抗輻照性能的提升。
[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.
【學(xué)位授予單位】：上海應(yīng)用技術(shù)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ174.1

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