分离式打拿极电子倍增器(Discrete Dynode Electron Multiplier,DDEM)作为一种真空电子倍增器件可以实现对电子、离子和光子等粒子的探测,具有增益高、寿命长、动态范围宽、耐轰击等优点,广泛应用于材料分析、高能物理、航空航天等领域...分离式打拿极电子倍增器(Discrete Dynode Electron Multiplier,DDEM)作为一种真空电子倍增器件可以实现对电子、离子和光子等粒子的探测,具有增益高、寿命长、动态范围宽、耐轰击等优点,广泛应用于材料分析、高能物理、航空航天等领域。传统DDEM一般由铜铍或银镁合金作为基底材料,经过氧化激活工艺制备而成,DDEM的性能依赖于基底材料的性能,由于氧化激活工艺复杂且合金材料的稳定性难以控制,造成后续制作出的打拿极性能难以保证。抛弃传统复杂的合金氧化工艺,采用原子层沉积(Atomic Layer Deposition,ALD)技术制备二次电子发射系数(Secondary Electron Yield,SEY)高而且稳定的氧化铝薄膜(SEY最大值为4.2),设计了一种盒栅式结构的DDEM,搭建了真空设备实现DDEM关键技术参数的测试评价,在直流状态下DDEM的增益可达2×10^(6),脉冲状态下增益可达1×10^(8),验证了ALD技术研制DDEM的可行性,解决了传统DDEM打拿极发射层材料严重依赖于金属合金成分和高温氧化激活工艺的难题,为今后研制更优性能的DDEM提供了良好的实验基础和新的技术方案。展开更多
7.62 cm(3英寸)光电倍增管(Photomultiplier Tube,PMT)是江门中微子实验(Jiangmen Underground Neutrino Observatory,JUNO)巨型探测器的重要组成部分,以此构成的一套独立探测系统,承担着独立物理测量、与50.8 cm(20英寸)PMT探测系统相...7.62 cm(3英寸)光电倍增管(Photomultiplier Tube,PMT)是江门中微子实验(Jiangmen Underground Neutrino Observatory,JUNO)巨型探测器的重要组成部分,以此构成的一套独立探测系统,承担着独立物理测量、与50.8 cm(20英寸)PMT探测系统相互检验等重要任务。为提高探测系统的可靠性,使每个7.62 cm PMT供电高压的单通道电流不超过10?A,研究了不同高压电流对7.62 cm PMT探测性能的影响。采用三种高压电流的分压器,对海南展创生产的型号为XP72B20(样管编号为70069)的7.62 cm PMT的性能进行实验测试,包括增益、能量分辨率、峰谷比和阳极输出信号的非线性。结果表明:不同分压电流对7.62 cm PMT性能的影响较小。这个结果为该7.62 cm PMT在JUNO探测器中使用小分压电流的方案提供了重要的实验依据。展开更多
Because of 3He shortage,sintillator is a promising alternative choice for neutron detection in the field of thermal neutron scattering and imaging.Also,the neutron detection efficiency is difficult to be determined.In...Because of 3He shortage,sintillator is a promising alternative choice for neutron detection in the field of thermal neutron scattering and imaging.Also,the neutron detection efficiency is difficult to be determined.In this paper,the efficiency for thermal neutron detection is presented by inorganic scintillator using probability principles,supposed that the material of scintillator is uniform in element distribution,and that attenuation length of scintillation light is longer than that of its thickness in the scintillator.The efficiencies for two pieces of lithium glass are determined by this method,indicating the method is useful for determining efficiency of thermal neutron detections.展开更多
The antineutrino detectors for the Daya Bay reactor neutrino experiment are liquid scintillator detectors designed to detect electron anti-neutrino via inverse beta interactions with high efficiency and low background...The antineutrino detectors for the Daya Bay reactor neutrino experiment are liquid scintillator detectors designed to detect electron anti-neutrino via inverse beta interactions with high efficiency and low backgrounds.Since the antineutrino detector will be installed and immerged in water Cherenkov detector and will run for 3 to 5 years,water tightness is critical to the successful operation of the antineutrino detectors.A special seal technique was used for this purpose.Three leak checking methods have been employed to ensure the seal quality.This paper describes the sealing method and leakage testing results.展开更多
The aim of the Daya Bay reactor antineutrino experiment is to determine the neutrino mixing angle 13 with a sensitivity of 0.01 or better at 90% confidence level.In order to improve the position resolution of both the...The aim of the Daya Bay reactor antineutrino experiment is to determine the neutrino mixing angle 13 with a sensitivity of 0.01 or better at 90% confidence level.In order to improve the position resolution of both the positron interaction and the neutron capture,the inside of the antineutrino detectors should be as unreflecting as possible.A black matt fluorocarbon paint is coated on the inner surface of the detectors made of 304L stainless steel to meet the physical requirement.This paint is compatible with mineral oil,has low radioactivity,is easy to spray and fast curing at normal temperatures.The coating has excellent performance such as good adhesive force,uniformity,compact,scratch and wear resistance,and so on.It is the first application of such paint to large physical devices.展开更多
文摘分离式打拿极电子倍增器(Discrete Dynode Electron Multiplier,DDEM)作为一种真空电子倍增器件可以实现对电子、离子和光子等粒子的探测,具有增益高、寿命长、动态范围宽、耐轰击等优点,广泛应用于材料分析、高能物理、航空航天等领域。传统DDEM一般由铜铍或银镁合金作为基底材料,经过氧化激活工艺制备而成,DDEM的性能依赖于基底材料的性能,由于氧化激活工艺复杂且合金材料的稳定性难以控制,造成后续制作出的打拿极性能难以保证。抛弃传统复杂的合金氧化工艺,采用原子层沉积(Atomic Layer Deposition,ALD)技术制备二次电子发射系数(Secondary Electron Yield,SEY)高而且稳定的氧化铝薄膜(SEY最大值为4.2),设计了一种盒栅式结构的DDEM,搭建了真空设备实现DDEM关键技术参数的测试评价,在直流状态下DDEM的增益可达2×10^(6),脉冲状态下增益可达1×10^(8),验证了ALD技术研制DDEM的可行性,解决了传统DDEM打拿极发射层材料严重依赖于金属合金成分和高温氧化激活工艺的难题,为今后研制更优性能的DDEM提供了良好的实验基础和新的技术方案。
文摘7.62 cm(3英寸)光电倍增管(Photomultiplier Tube,PMT)是江门中微子实验(Jiangmen Underground Neutrino Observatory,JUNO)巨型探测器的重要组成部分,以此构成的一套独立探测系统,承担着独立物理测量、与50.8 cm(20英寸)PMT探测系统相互检验等重要任务。为提高探测系统的可靠性,使每个7.62 cm PMT供电高压的单通道电流不超过10?A,研究了不同高压电流对7.62 cm PMT探测性能的影响。采用三种高压电流的分压器,对海南展创生产的型号为XP72B20(样管编号为70069)的7.62 cm PMT的性能进行实验测试,包括增益、能量分辨率、峰谷比和阳极输出信号的非线性。结果表明:不同分压电流对7.62 cm PMT性能的影响较小。这个结果为该7.62 cm PMT在JUNO探测器中使用小分压电流的方案提供了重要的实验依据。
基金Supported by the National Natural Science Foundation of China(Grant No.10875140)
文摘Because of 3He shortage,sintillator is a promising alternative choice for neutron detection in the field of thermal neutron scattering and imaging.Also,the neutron detection efficiency is difficult to be determined.In this paper,the efficiency for thermal neutron detection is presented by inorganic scintillator using probability principles,supposed that the material of scintillator is uniform in element distribution,and that attenuation length of scintillation light is longer than that of its thickness in the scintillator.The efficiencies for two pieces of lithium glass are determined by this method,indicating the method is useful for determining efficiency of thermal neutron detections.
基金supported by the Ministry of Science and Technology of the People's Republic of China (Grant No. 2006CB808102)
文摘The antineutrino detectors for the Daya Bay reactor neutrino experiment are liquid scintillator detectors designed to detect electron anti-neutrino via inverse beta interactions with high efficiency and low backgrounds.Since the antineutrino detector will be installed and immerged in water Cherenkov detector and will run for 3 to 5 years,water tightness is critical to the successful operation of the antineutrino detectors.A special seal technique was used for this purpose.Three leak checking methods have been employed to ensure the seal quality.This paper describes the sealing method and leakage testing results.
基金supported in part by the Ministry of Science and Technology of China (Gramt No. 2006CB808100)supported by the National Natural Science Foundation of China(Grant No. 11005117)
文摘The aim of the Daya Bay reactor antineutrino experiment is to determine the neutrino mixing angle 13 with a sensitivity of 0.01 or better at 90% confidence level.In order to improve the position resolution of both the positron interaction and the neutron capture,the inside of the antineutrino detectors should be as unreflecting as possible.A black matt fluorocarbon paint is coated on the inner surface of the detectors made of 304L stainless steel to meet the physical requirement.This paint is compatible with mineral oil,has low radioactivity,is easy to spray and fast curing at normal temperatures.The coating has excellent performance such as good adhesive force,uniformity,compact,scratch and wear resistance,and so on.It is the first application of such paint to large physical devices.
