中子探测技术广泛用于国土安全、核材料安全检测以及高能物理等领域,由于3He资源紧缺,近年来急需开发出能够同时甄别中子/伽马的新型闪烁晶体,Cs_(2)LaLiBr_(6):Ce(CLLB:Ce)晶体具有良好的中子/伽马甄别能力、优异的能量分辨率以及高的...中子探测技术广泛用于国土安全、核材料安全检测以及高能物理等领域,由于3He资源紧缺,近年来急需开发出能够同时甄别中子/伽马的新型闪烁晶体,Cs_(2)LaLiBr_(6):Ce(CLLB:Ce)晶体具有良好的中子/伽马甄别能力、优异的能量分辨率以及高的光输出,但其中子/伽马甄别性能有待进一步提高。本研究采用垂直布里奇曼法成功生长了Zr^(4+)共掺杂的CLLB:Ce晶体。通过不同表征手段研究了Zr^(4+)共掺杂CLLB:Ce晶体的结构和组分,结果表明Zr^(4+)成功掺入基质材料且对基质晶体结构不产生明显的影响,Zr^(4+)共掺杂后没有产生新的发光中心,紫外衰减时间约为27.0 ns,仍具有较快的荧光衰减。Zr^(4+)共掺杂CLLB:Ce晶体的品质因子(Figure of Merit,FOM)从1.2提高到1.5,表明其中子/伽马甄别能力得到改善。结合热稳定性和闪烁衰减时间,探讨了衰减时间对FOM的影响机制,Zr^(4+)共掺杂可以抑制浅电子陷阱和Vk中心,减少电子捕获和脱陷过程,使Ce^(3+)直接捕获的概率大大增加,从而表现出更快的衰减速率。本研究显示,Zr^(4+)共掺杂CLLB:Ce晶体在中子/伽马探测领域具有潜在的应用前景。展开更多
运用燃烧法制备出单相(Y,Ce)_2Zr_2O_7纳米粉体,利用X射线衍射(X-ray Diffraction,XRD)与扫描电子显微镜(Scanning Electron Microscope,SEM)等分析表征手段,研究了Y/Ce比、燃烧剂、烧结温度对晶体结构和粉体形貌以及颗粒大小的影响.同...运用燃烧法制备出单相(Y,Ce)_2Zr_2O_7纳米粉体,利用X射线衍射(X-ray Diffraction,XRD)与扫描电子显微镜(Scanning Electron Microscope,SEM)等分析表征手段,研究了Y/Ce比、燃烧剂、烧结温度对晶体结构和粉体形貌以及颗粒大小的影响.同时,通过荧光光谱(Photoluminescence,PL)对Eu^(3+)离子掺杂的纳米粉体的发光性能进行了研究.结果表明,利用燃烧法可以快速高效地获得不同Y/Ce比的单相(Y,Ce)_2Zr_2O_7纳米粉体,Ce^(3+)离子的掺杂可以有效改善粉体分散性,且对晶体能带结构有一定影响,进而影响粉体的荧光性能.展开更多
The translucent GGAG:Ce/glass composites are prepared successfully by ball-milling,tableting,and pressureless sintering.The thickness of composites is about 400μm.The x-ray diffraction(XRD),differential scanning calo...The translucent GGAG:Ce/glass composites are prepared successfully by ball-milling,tableting,and pressureless sintering.The thickness of composites is about 400μm.The x-ray diffraction(XRD),differential scanning calorimetry(DSC),density of composite materials are measured and discussed systematically.The scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS)elemental mapping are employed to analyze the particle size,the shape of powders,and the distribution of GGAG:Ce particles in the glass matrix,respectively.The decay time,ultraviolet,(UV),x-ray excitation luminescence spectra,and temperature spectra are studied.The results show that the composite materials have high light output,good thermostability,and short decay time.The method adopted in this work is an effective method to reduce the preparation time and cost of the sample.The ultralow afterglow indicates that the composite materials have an opportunity to be used for x-ray detection and imaging.展开更多
We discuss the synthesis of Na2W2O7 polycrystalline materials based on the TG-DSC experiment.The luminescence properties of the Na_(2)W_(2)O_(7) crystal are investigated using the Nd:YAG laser as the excitation source...We discuss the synthesis of Na2W2O7 polycrystalline materials based on the TG-DSC experiment.The luminescence properties of the Na_(2)W_(2)O_(7) crystal are investigated using the Nd:YAG laser as the excitation source.It is found that the maximum emission peak of the Na2W2O7 crystal is at 525 nm.The 525-nm luminescence decay has two components.One has decay time 1.8s and the other 49.1μs.By comparing this results with that of the Na_(2)W_(4)O_(13) crystal,it is assumed that the 525-nm luminescence emission of the Na_(2)W_(2)O_(7) crystal originates from the WO^(6−)6 octahedral group.展开更多
文摘中子探测技术广泛用于国土安全、核材料安全检测以及高能物理等领域,由于3He资源紧缺,近年来急需开发出能够同时甄别中子/伽马的新型闪烁晶体,Cs_(2)LaLiBr_(6):Ce(CLLB:Ce)晶体具有良好的中子/伽马甄别能力、优异的能量分辨率以及高的光输出,但其中子/伽马甄别性能有待进一步提高。本研究采用垂直布里奇曼法成功生长了Zr^(4+)共掺杂的CLLB:Ce晶体。通过不同表征手段研究了Zr^(4+)共掺杂CLLB:Ce晶体的结构和组分,结果表明Zr^(4+)成功掺入基质材料且对基质晶体结构不产生明显的影响,Zr^(4+)共掺杂后没有产生新的发光中心,紫外衰减时间约为27.0 ns,仍具有较快的荧光衰减。Zr^(4+)共掺杂CLLB:Ce晶体的品质因子(Figure of Merit,FOM)从1.2提高到1.5,表明其中子/伽马甄别能力得到改善。结合热稳定性和闪烁衰减时间,探讨了衰减时间对FOM的影响机制,Zr^(4+)共掺杂可以抑制浅电子陷阱和Vk中心,减少电子捕获和脱陷过程,使Ce^(3+)直接捕获的概率大大增加,从而表现出更快的衰减速率。本研究显示,Zr^(4+)共掺杂CLLB:Ce晶体在中子/伽马探测领域具有潜在的应用前景。
文摘运用燃烧法制备出单相(Y,Ce)_2Zr_2O_7纳米粉体,利用X射线衍射(X-ray Diffraction,XRD)与扫描电子显微镜(Scanning Electron Microscope,SEM)等分析表征手段,研究了Y/Ce比、燃烧剂、烧结温度对晶体结构和粉体形貌以及颗粒大小的影响.同时,通过荧光光谱(Photoluminescence,PL)对Eu^(3+)离子掺杂的纳米粉体的发光性能进行了研究.结果表明,利用燃烧法可以快速高效地获得不同Y/Ce比的单相(Y,Ce)_2Zr_2O_7纳米粉体,Ce^(3+)离子的掺杂可以有效改善粉体分散性,且对晶体能带结构有一定影响,进而影响粉体的荧光性能.
基金the National Natural Science Foundation of China(Grant Nos.11975220,51972291,11575170,and 11605194)。
文摘The translucent GGAG:Ce/glass composites are prepared successfully by ball-milling,tableting,and pressureless sintering.The thickness of composites is about 400μm.The x-ray diffraction(XRD),differential scanning calorimetry(DSC),density of composite materials are measured and discussed systematically.The scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS)elemental mapping are employed to analyze the particle size,the shape of powders,and the distribution of GGAG:Ce particles in the glass matrix,respectively.The decay time,ultraviolet,(UV),x-ray excitation luminescence spectra,and temperature spectra are studied.The results show that the composite materials have high light output,good thermostability,and short decay time.The method adopted in this work is an effective method to reduce the preparation time and cost of the sample.The ultralow afterglow indicates that the composite materials have an opportunity to be used for x-ray detection and imaging.
基金by the National Natural Science Foundation of China under Grant Nos 91022028 and 51002147.
文摘We discuss the synthesis of Na2W2O7 polycrystalline materials based on the TG-DSC experiment.The luminescence properties of the Na_(2)W_(2)O_(7) crystal are investigated using the Nd:YAG laser as the excitation source.It is found that the maximum emission peak of the Na2W2O7 crystal is at 525 nm.The 525-nm luminescence decay has two components.One has decay time 1.8s and the other 49.1μs.By comparing this results with that of the Na_(2)W_(4)O_(13) crystal,it is assumed that the 525-nm luminescence emission of the Na_(2)W_(2)O_(7) crystal originates from the WO^(6−)6 octahedral group.
