The GECAM series of satellites utilizes LaBr_(3)(Ce),LaBr_(3)(Ce,Sr),and NaI(Tl)crystals as sensitive materials for gamma-ray detectors(GRDs).To investigate the nonlinearity in the detection of low-energy gamma rays a...The GECAM series of satellites utilizes LaBr_(3)(Ce),LaBr_(3)(Ce,Sr),and NaI(Tl)crystals as sensitive materials for gamma-ray detectors(GRDs).To investigate the nonlinearity in the detection of low-energy gamma rays and address the errors in the calibration of the E-C relationship,comprehensive tests and comparative studies of the three aforementioned crystals were conducted using Compton electrons,radioactive sources,and mono-energetic X-rays.The nonlinearity test results of the Compton electrons and X-rays demonstrated substantial differences,with all three crystals presenting a higher nonlinearity for X/-rays than for Compton electrons.Despite the LaBr_(3)(Ce)and LaBr_(3)(Ce,Sr)crystals having higher absolute light yields,they exhibited a noticeable nonlinear decrease in the light yield,especially at energies below 400 keV.The NaI(Tl)crystal demonstrated an"excess"light output in the 6-200 keV range,reaching a maximum"excess"of 9.2%at 30 keV in the X-ray testing and up to 15.5%at 14 keV during Compton electron testing,indicating a significant advantage in the detection of low-energy gamma rays.Furthermore,we explored the underlying causes of the observed nonlinearity in these crystals.This study not only elucidates the detector responses of GECAM,but also initiates a comprehensive investigation of the nonlinearity of domestically produced lanthanum bromide and sodium iodide crystals.展开更多
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
基金This work was supported by the National Key Research and Development Program(Nos.2022YFB3503600 and 2021YFA0718500)Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDA15360102)National Natural Science Foundation of China(Nos.12273042 and 12075258).
文摘The GECAM series of satellites utilizes LaBr_(3)(Ce),LaBr_(3)(Ce,Sr),and NaI(Tl)crystals as sensitive materials for gamma-ray detectors(GRDs).To investigate the nonlinearity in the detection of low-energy gamma rays and address the errors in the calibration of the E-C relationship,comprehensive tests and comparative studies of the three aforementioned crystals were conducted using Compton electrons,radioactive sources,and mono-energetic X-rays.The nonlinearity test results of the Compton electrons and X-rays demonstrated substantial differences,with all three crystals presenting a higher nonlinearity for X/-rays than for Compton electrons.Despite the LaBr_(3)(Ce)and LaBr_(3)(Ce,Sr)crystals having higher absolute light yields,they exhibited a noticeable nonlinear decrease in the light yield,especially at energies below 400 keV.The NaI(Tl)crystal demonstrated an"excess"light output in the 6-200 keV range,reaching a maximum"excess"of 9.2%at 30 keV in the X-ray testing and up to 15.5%at 14 keV during Compton electron testing,indicating a significant advantage in the detection of low-energy gamma rays.Furthermore,we explored the underlying causes of the observed nonlinearity in these crystals.This study not only elucidates the detector responses of GECAM,but also initiates a comprehensive investigation of the nonlinearity of domestically produced lanthanum bromide and sodium iodide crystals.
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。
