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Chinese Physics Letters 2015年第3期32卷 30-33页

作者：王晓冬张俊伟胡碧涛杨贺润段利敏鲁辰桂胡荣江张春晖周健荣杨磊安旅行罗文 School of Nuclear Science and Technology University of South China Hengyang 421001 Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 School of Nuclear Science and Technology Lanzhou University Lanzhou 730000 Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 LWD Logging Center China Petroleum Logging CO. LTD. Xi'an 710000

A detector for fast neutrons based on a 10 × 10 cm^2 triple gas electron multiplier （gem） device is developed and tested. A neutron converter, which is a high density polyethylene （HDPE） layer, is combined with the triple gem detector cathode and placed inside the detector, in the path of the incident neutrons. The detector is tested by obtaining the energy deposition spectrum with an Am Be neutron source in the Institute of Modern Physics （IMP） at Lanzhou. In the present work we report the results of the tests and compare them with those of simulations. The transport of fast neutrons and their interactions with the different materials in the detector are simulated with the GEANT4 code, to understand the experimental results. The detector displays a clear response to the incident fast neutrons. However, an unexpected disagreement in the energy dependence of the response between the simulated and measured spectra is observed. The neutron sources used in our simulation include deuterium-tritium （DT, 14 MeV）, deuterium-deuterium （DD, 2.45 MeV）, and Am Be sources. The simulation results also show that among the secondary particles generated by the incident neutron, the main contributions to the total energy deposition are from recoil protons induced in hydrogen-rich HDPE or Kapton （gem material）, and activation photons induced by neutron interaction with Ar atoms. Their contributions account for 90% of the total energy deposition. In addition, the dependence of neutron deposited energy spectrum on the composition of the gas mixture is presented.

关键词： gem Simulation Comparison of Experiment and Simulation of the triple gem-Based Fast Neutron Detector

Design and optimization of resistive anode for a two-dimensional imaging gem detector

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Chinese Physics C 2016年第8期40卷 90-95页

作者：鞠旭东董明义赵逸琛周传兴欧阳群 State Key Laboratory of Particle Detection and Electronics Beijing 100049 China Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China University of Chinese Academy of Sciences Beijing 100049 China Zhengzhou University Zhengzhou 450001 China

A resistive anode for two-dimensional imaging detectors, which consists of a series of high resistivity pads surrounded by low resistivity strips, can provide good spatial resolution while reducing the number of electronics channels required. The optimization of this kind of anode has been studied by both numerical simulations and experimental tests. It is found that to obtain good detector performance, the resistance ratio of the pads to the strips should be larger than 5, the nonuniformity of the pad surface resistivity should be less than 20%, a smaller pad width leads to a smaller spatial resolution, and when the pad width is 6 mm, the spatial resolution （a） can reach about 105 μm. Based on the study results, a 2-D gem detector prototype with optimized resistive anode is constructed and a good imaging performance is achieved.

关键词： resistive anode gem two dimensional detector spatial resolution imaging distortion

A large-area gem detector using a novel self-stretching technique

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Chinese Physics C 2015年第4期39卷 51-54页

作者：尤文豪周意李澄陈宏芳邵明孙勇杰唐泽波刘建北 State Key Laboratory of Particle Detection and Electronics University of Science and Technology of China

A Gas Electron Multiplier （gem） detector with an effective area of 300 mm×300 mm has been constructed using a novel self-stretching technique, which allows a highly flexible and efficient gem detector assembly free of glue or spacers. This makes the re-opening and repair of the gem detectors possible and significantly reduces the scrap rate in the mass production of large-area gem detectors. With the technique, the assembly time can be limited to a few hours, a factor of ten improvement compared to that using gluing techniques. The details of design and assembly procedure of the 300 mm×300 mm gem detector are described in this paper. This detector was tested with 8 keV X-rays for the effective gain, energy resolution and performance uniformity. The results show that the typical energy resolution is 20% at an effective gain of about 10-4, with fairly good uniformity.

关键词： gem self-stretching effective gas gain energy resolution uniformity

Study of measuring methods on spatial resolution of a gem imaging detector

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Chinese Physics C 2012年第3期36卷 228-234页

作者：吕新宇樊瑞睿陈元柏欧阳群刘荣光刘鹏祁辉荣张健赵平平赵东旭赵豫斌章红宇盛华义董丽媛 Institute of High Energy Physics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences State Key Laboratory of Particle Detection and Electronics School of Nuclear Science and Technology Lanzhou University

In this paper, the limitations of the common method measuring intrinsic spatial resolution of the gem imaging detector are presented. Through theoretical analysis and experimental verification, we have improved the common method to avoid these limitations. Using these improved methods, a more precise measurement of intrinsic spatial resolutions are obtained.

关键词： spatial resolution imaging detector gem convolution deconvolution

Neutron beam monitor based on a boron-coated gem

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Chinese Physics C 2011年第7期35卷 668-674页

作者：周健荣孙志嘉刘贲王艳凤杨桂安周良许虹董静杨雷李仪 Institute of High Energy Physics Chinese Academy of Sciences Huazhong Normal University Dongguan University of Technology

A new thermal neutron beam monitor with a Gas Electron Multiplier （gem） is developed to meet the needs of the next generation of neutron facilities. A prototype chamber has been constructed with two 100 mm×100 mm gem foils. Enriched boron-10 is coated on one surface of the aluminum cathode plate as the neutron convertor. 96 channel pads with an area of 8 mm×8 mm each are used for fast signal readout. In order to study the basic characteristics of a boron-coated gem, several irradiation tests were carried out with of source ^239pu and neutron source ^241Am（Be）. The signal induced by the neutron source has a high signal-to-noise ratio. A clear image obtained from of source ^239pu is presented, which shows that the neutron beam monitor based on a boron-coated gem has a good two-dimensional imaging ability.

关键词： boron-coated gem neutron beam monitor spallation neutron source

Development of a multi-channel readout ASIC for a fast neutron spectrometer based on gem-TPC

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Chinese Physics C 2014年第10期38卷 39-43页

作者：何力邓智刘以农李玉兰 Key Laboratory of Particle & Radiation Imaging (Tsinghua University) Ministry of Education Department of Engineering Physics Tsinghua University

A multi-channel front-end ASIC has been developed for a fast neutron spectrometer based on Gas Electron Multiplier （gem）-Time Projection Chamber （TPC）. Charge Amplifier and Shaping Amplifier for gem （CASAgem） integrates 16＋1 channels： 16 channels for anodes and 1 channel for cathode. The gain and the shaping time are adjustable from 2 to 40 mV/fC and from 20 to 80 ns, respectively. The prototype ASIC is fabricated in 0.35 μm CMOS process. An evaluation Print Circuit Board （PCB） was also developed for chip tests. In total 20 chips have been tested. The integrated nonlinearity is less than 1%. The equivalent noise electrons is less than 2000e when the input capacitor is 50 pF. The time jitter is less than 1 ns. The design and the test results are presented in the paper.

关键词： front-end readout electronics ASIC TPC gem

Electron transmission ef f iciency of gating-gem foil for TPC

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Chinese Physics C 2012年第4期36卷 339-343页

作者：谢文庆黄孟李婷田阳李玉兰李元景 Department of Engineering Physics Tsinghua University Key Laboratory of Particle & Radiation Imaging (Tsinghua University) Ministry of Education

In a TPC, ion feedback from the readout detector can cause a space-charge effect and distort the electrical field in the drift region. Gating is one of the effective methods to solve this problem, which can block ions at the expense of losing a certain amount of primary electrons. Compared with the traditional design with a wire structure, gating based on gem foil is more attractive because of its simplicity. In this paper, the factors influencing the electron transmission efficiency are studied with simulations and experiments. After optimizing all these parameters, an electron transmission efficiency over 80% is obtained.

关键词： gem gating electron transmission efficiency TPC

Computer Aided Design Technology for Convex Faceted gem Cuts Based on the Half-Edge Data Structure

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Journal of Beijing Institute of Technology 2019年第3期28卷 585-597页

作者： Linhong Xu Xiangnan Li Jianhua Rao Yuan Han Zhipeng Li Jichun Li School of Mechanical Engineering and Electronic Information China University of Geosciences (Wuhan)

Aiming to increase the efficiency of gem design and manufacturing, a new method in computer-aided-design (CAD) of convex faceted gem cuts (CFGC) based on Half-edge data structure (HDS), including the algorithms for the implementation is presented in this work. By using object-oriented methods, geometrical elements of CFGC are classified and responding geometrical feature classes are established. Each class is implemented and embedded based on the gem process. Matrix arithmetic and analytical geometry are used to derive the affine transformation and the cutting algorithm. Based on the demand for a diversity of gem cuts, CAD functions both for free-style faceted cuts and parametric designs of typical cuts and visualization and human-computer interactions of the CAD system including two-dimensional and three-dimensional interactions have been realized which enhances the flexibility and universality of the CAD system. Furthermore, data in this CAD system can also be used directly by the gem CAM module, which will promote the gem CAD/CAM integration.

关键词： Half-edge data structure convex faceted gem cuts (CFGC) computer aided design (CAD)

基于gem的裂变时间投影室的研制及实验方法研究

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基于GEM的裂变时间投影室的研制及实验方法研究

作者：何山浩玮兰州大学

学位级别：硕士

原子核裂变反应已被广泛应用于军事、能源等多个领域,但是人们对它的研究仍在继续。由于传统测量方法的局限性,对裂变碎片径迹的精确检测仍然是一个棘手的问题。气体电子倍增器（gem）的发明及其与时间投影室（TPC）探测技术的结合,为... 详细信息

原子核裂变反应已被广泛应用于军事、能源等多个领域,但是人们对它的研究仍在继续。由于传统测量方法的局限性,对裂变碎片径迹的精确检测仍然是一个棘手的问题。气体电子倍增器（gem）的发明及其与时间投影室（TPC）探测技术的结合,为实现对裂变碎片进行多参数关联测量提供了条件。本文工作即为基于gem的裂变时间投影室（FTPC）的研制及其实验方法研究。FTPC由三部分构成,分别是:用于提供稳定气体环境的流气式稳压靶室;探测器的核心部分,获取裂变碎片核信息的gem-based TPC探测系统;以及总计1664路的读出电子学及数据处理系统。为了延长裂变碎片径迹,减少测量结果的空间堆叠,从而获取裂变碎片更精确的位置和能量信息,FTPC被设计应用于低气压环境中。但是当前对于气体探测器在低气压环境中的工作特性研究还不完善,因此使用Fe源对FTPC在不同气压下的工作特性进行了测试。当工作气压降低时,FTPC正常工作的电压范围也会降低,能量分辨率会先变好,并在气压在300 m Bar左右达到最佳,约17%,之后则快速变差。当FTPC的工作状态不变时,gem的膜间约化场强并非保持不变,而是会随着气压下降而上升。此外,为了消除读出电路电荷泄放速度差异引入的系统误差,提出了信号的时间修正方法:通过分离信号中的指数衰减部分,获得原始高斯信号。本文的数据处理皆基于此方法。使用Amα源对FTPC的基本性能进行了测试。重建了α粒子的二维与三维径迹,在此基础上给出了FTPC在X-Y平面和Z方向的空间分辨,分别为511.1μm和610.2μm。同时,使用SRIM软件模拟了α粒子在850 m Bar和550 m Bar的P10气体中的能损,对比了α粒子产生的径迹信号并完成了对FTPC的能损标定。目前FTPC的性能测试实验以及数据处理方法总结已经基本完成,探测器情况良好,具备探测快中子诱发U产生的裂变碎片能力。

关键词： gem TPC 快中子诱发裂变反应裂变碎片径迹重建比能损