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
介绍了一种自主研制的新型电荷灵敏型三级放大器,其电路设计主要采用ADA4817高速低噪声集成运算放大芯片,该三级放大器噪声低、稳定性好、电路结构简单、性价比高、检修更换方便,可以不失真地放大上升时间在ns级的信号,放大器输出信号...介绍了一种自主研制的新型电荷灵敏型三级放大器,其电路设计主要采用ADA4817高速低噪声集成运算放大芯片,该三级放大器噪声低、稳定性好、电路结构简单、性价比高、检修更换方便,可以不失真地放大上升时间在ns级的信号,放大器输出信号质量优异,可配合后续的多道分析器MCA8000D读取微通道板(microchannel plate,MCP)组件或单通道电子倍增器(single-channel electron multiplier,CEM)的单光电子谱,测试结果表明:自主设计的ADA4817型放大器在一定的方波标定脉冲信号下,其基线的宽度小于2 m V,上升沿时间约为800 ns,幅值约为40 m V,性能接近或略优于A250型放大器,可以更好地配合后续的多道分析器MCA8000D进行输出波形的分析和处理,完全满足MCP或CEM探测器的脉冲性能测试需求。展开更多
A new concept of neutron detector based on Gas Electron Multiplier(GEM) technology is presented in this paper,in which a novel multi-layer high density polyethylene(HDPE) as neutron-to-proton converter is proposed and...A new concept of neutron detector based on Gas Electron Multiplier(GEM) technology is presented in this paper,in which a novel multi-layer high density polyethylene(HDPE) as neutron-to-proton converter is proposed and studied with Geant4 toolkit for fast 14 MeV neutron.Our preliminary results show that the detection efficiency of the detector with 400 converter units is higher than 2.3% and reconstruction accuracy of the incident neutron position is higher than 2.6%.展开更多
A semiconductor PEC etching method is applied to fabricate the n-type silicon deep micropore channel array. In this method, it is important to arrange the direction of the micropore array along the crystal orientation...A semiconductor PEC etching method is applied to fabricate the n-type silicon deep micropore channel array. In this method, it is important to arrange the direction of the micropore array along the crystal orientation of the Si substrate. Otherwise, serious lateral erosion will happen. The etching process is also relative to the light intensity and HF concentration. 5% HF concentration and 10-15 cm distance between the light source and the silicon wafer are demonstrated to be the best in our experiments. The n-type silicon deep micropore channel array with aperture of 3/2m and aspect ratio of 40-60, whose inner walls are smooth, is finally obtained.展开更多
Gas electron multiplier (GEM) as a novel gas detector,due to it’s simple structure,high performance,well compatibility etc.,is widely used in high-energy physics,nuclear physics and other fields.In this review,the pr...Gas electron multiplier (GEM) as a novel gas detector,due to it’s simple structure,high performance,well compatibility etc.,is widely used in high-energy physics,nuclear physics and other fields.In this review,the principle,recent achievements,developments and applications of GEM are mainly described.展开更多
Introduction THick Gas Electron Multiplier(THGEM)is considered in many UV photon detector applications.It has the capability of detecting single photon and imaging with high sensitivity.Operating parameters such as ch...Introduction THick Gas Electron Multiplier(THGEM)is considered in many UV photon detector applications.It has the capability of detecting single photon and imaging with high sensitivity.Operating parameters such as choice of gas mixture,pressure,drift field,drift gap,multiplication voltage,induction field and induction gap play an important role in deciding the spatial resolution of the detector.Detailed simulation study enables to optimize the above-mentioned parameters for a given THGEM-based imaging detector and hence to achieve improved performance for the same.Materials and methods Simulation,using ANSYS and Garfield++,starts with the release of primary electrons at random coordinates on the photocathode plane.They are tracked as they pass through the drift gap and THGEM hole till the electron cloud reaches anode plane.Distribution of electron cloud on the anode plane along X and Y axis is plotted in histogram and fitted with Gaussian function to determine spatial resolution.Ar/CO_(2)(70:30)mixture,which shows higher ETE and lower transverse diffusion,is chosen for this simulation study.Conclusion Transverse diffusion has a major impact on both ETE and the spatial resolution.Lower transverse diffusion coefficient is always desired for having better resolution as well as for ETE.It is found from the simulation study that higher gas pressure,lower drift field and induction field,smaller drift and induction gap can provide optimum detection efficiency with the best spatial resolution.The simulation method proposed here can also be extended to X-ray imaging detectors.展开更多
为解决电子倍增器、场发射阴极和粒子/光子探测器现有阴极材料次级发射系数低且发射不稳定的问题,对微波等离子体化学气相沉积(Microwave Plasma Chemical Vapor Deposition,MPCVD)法结合H等离子体表面处理工艺制备的不同B2H6/CH4浓度...为解决电子倍增器、场发射阴极和粒子/光子探测器现有阴极材料次级发射系数低且发射不稳定的问题,对微波等离子体化学气相沉积(Microwave Plasma Chemical Vapor Deposition,MPCVD)法结合H等离子体表面处理工艺制备的不同B2H6/CH4浓度的硼掺杂金刚石薄膜的次级发射能力进行了研究。样品表面扫描电子显微镜和拉曼光谱分析结果显示,硼掺杂金刚石膜表面形貌与未掺杂的金刚石膜相似,样品表面均为高纯度的金刚石相。将置于空气中数日且未经任何表面处理的硼掺杂金刚石样品进行次级电子发射性能测试,结果显示一次电子入射能量为1keV时,得到高达18.3的二次电子发射系数。试验证实这种具有高二次电子发射系数的硼掺杂金刚石膜,暴露空气中由于表面氧化会破坏其表面的负电子亲和势,而真空中加热会使表面重新恢复负电子亲和势,这种负电子亲和势的完整保留,提高了该材料次级发射的稳定性,在器件中具有重要的应用前景。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。
文摘介绍了一种自主研制的新型电荷灵敏型三级放大器,其电路设计主要采用ADA4817高速低噪声集成运算放大芯片,该三级放大器噪声低、稳定性好、电路结构简单、性价比高、检修更换方便,可以不失真地放大上升时间在ns级的信号,放大器输出信号质量优异,可配合后续的多道分析器MCA8000D读取微通道板(microchannel plate,MCP)组件或单通道电子倍增器(single-channel electron multiplier,CEM)的单光电子谱,测试结果表明:自主设计的ADA4817型放大器在一定的方波标定脉冲信号下,其基线的宽度小于2 m V,上升沿时间约为800 ns,幅值约为40 m V,性能接近或略优于A250型放大器,可以更好地配合后续的多道分析器MCA8000D进行输出波形的分析和处理,完全满足MCP或CEM探测器的脉冲性能测试需求。
基金supported by the National Natural Science Foundation of China (Grant Nos.11075069,11075068,91026021 and 11135002)
文摘A new concept of neutron detector based on Gas Electron Multiplier(GEM) technology is presented in this paper,in which a novel multi-layer high density polyethylene(HDPE) as neutron-to-proton converter is proposed and studied with Geant4 toolkit for fast 14 MeV neutron.Our preliminary results show that the detection efficiency of the detector with 400 converter units is higher than 2.3% and reconstruction accuracy of the incident neutron position is higher than 2.6%.
文摘A semiconductor PEC etching method is applied to fabricate the n-type silicon deep micropore channel array. In this method, it is important to arrange the direction of the micropore array along the crystal orientation of the Si substrate. Otherwise, serious lateral erosion will happen. The etching process is also relative to the light intensity and HF concentration. 5% HF concentration and 10-15 cm distance between the light source and the silicon wafer are demonstrated to be the best in our experiments. The n-type silicon deep micropore channel array with aperture of 3/2m and aspect ratio of 40-60, whose inner walls are smooth, is finally obtained.
文摘Gas electron multiplier (GEM) as a novel gas detector,due to it’s simple structure,high performance,well compatibility etc.,is widely used in high-energy physics,nuclear physics and other fields.In this review,the principle,recent achievements,developments and applications of GEM are mainly described.
文摘Introduction THick Gas Electron Multiplier(THGEM)is considered in many UV photon detector applications.It has the capability of detecting single photon and imaging with high sensitivity.Operating parameters such as choice of gas mixture,pressure,drift field,drift gap,multiplication voltage,induction field and induction gap play an important role in deciding the spatial resolution of the detector.Detailed simulation study enables to optimize the above-mentioned parameters for a given THGEM-based imaging detector and hence to achieve improved performance for the same.Materials and methods Simulation,using ANSYS and Garfield++,starts with the release of primary electrons at random coordinates on the photocathode plane.They are tracked as they pass through the drift gap and THGEM hole till the electron cloud reaches anode plane.Distribution of electron cloud on the anode plane along X and Y axis is plotted in histogram and fitted with Gaussian function to determine spatial resolution.Ar/CO_(2)(70:30)mixture,which shows higher ETE and lower transverse diffusion,is chosen for this simulation study.Conclusion Transverse diffusion has a major impact on both ETE and the spatial resolution.Lower transverse diffusion coefficient is always desired for having better resolution as well as for ETE.It is found from the simulation study that higher gas pressure,lower drift field and induction field,smaller drift and induction gap can provide optimum detection efficiency with the best spatial resolution.The simulation method proposed here can also be extended to X-ray imaging detectors.
文摘为解决电子倍增器、场发射阴极和粒子/光子探测器现有阴极材料次级发射系数低且发射不稳定的问题,对微波等离子体化学气相沉积(Microwave Plasma Chemical Vapor Deposition,MPCVD)法结合H等离子体表面处理工艺制备的不同B2H6/CH4浓度的硼掺杂金刚石薄膜的次级发射能力进行了研究。样品表面扫描电子显微镜和拉曼光谱分析结果显示,硼掺杂金刚石膜表面形貌与未掺杂的金刚石膜相似,样品表面均为高纯度的金刚石相。将置于空气中数日且未经任何表面处理的硼掺杂金刚石样品进行次级电子发射性能测试,结果显示一次电子入射能量为1keV时,得到高达18.3的二次电子发射系数。试验证实这种具有高二次电子发射系数的硼掺杂金刚石膜,暴露空气中由于表面氧化会破坏其表面的负电子亲和势,而真空中加热会使表面重新恢复负电子亲和势,这种负电子亲和势的完整保留,提高了该材料次级发射的稳定性,在器件中具有重要的应用前景。
