A double thick GEM (THGEM) detector with thin THGEM foils and small holes was constructed. In order to optimize the operation parameters of the detector, a simulation study of the detector was carried out using ANSYS ...A double thick GEM (THGEM) detector with thin THGEM foils and small holes was constructed. In order to optimize the operation parameters of the detector, a simulation study of the detector was carried out using ANSYS and Garfield program. Some important characteristics, including primary electron transparency, avalanche development and the secondary electron loss were calculated. Parameters, such as electric field and gas choice were optimized.展开更多
Among the various micro-pattern gas detectors (MPGD) that are available, the gas electron multiplier (GEM) detector is an attractive gas detector that has been used in particle physics experiments. However, the GEM de...Among the various micro-pattern gas detectors (MPGD) that are available, the gas electron multiplier (GEM) detector is an attractive gas detector that has been used in particle physics experiments. However, the GEM detector usually needs thousands of preamplifier units for its large number of micro-pattern readout strips or pads, which leads to considerable difficulties and complexities for front end electronics (FEE). Nowadays, by making use of complementary metal-oxide semiconductor (CMOS)-based application specific integrated circuit (ASIC), it is fea- sible to integrate hundreds of preamplifier units and other signal process circuits in a small-sized chip, which can be bound to the readout strips or pads of a micro-pattern particle detector (MPPD). Therefore, CMOS ASIC may provide an ideal solution to the readout problem of MPPD. In this article, a triple GEM detector is constructed and one of its readout strips is connected to a CMOS charge-sensitive preamplifier chip. The chip was exposed to an 55Fe source of 5.9 keV X-ray, and the amplitude spectrum of the chip was tested, and it was found that the energy resolution was approximately 27%, which indicates that the chip can be used in triple GEM detectors.展开更多
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 elect...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.展开更多
In recent years,gas electron multiplier(GEM)neutron detectors have been developing towards high spatial resolution and high dynamic counting range.We propose a novel concept of an Al stopping layer to enable the detec...In recent years,gas electron multiplier(GEM)neutron detectors have been developing towards high spatial resolution and high dynamic counting range.We propose a novel concept of an Al stopping layer to enable the detector to achieve sub-millimeter(sub-mm)spatial resolution.The neutron conversion layer is coated with the Al stopping layer to limit the emission angle of ions into the drift region.The short track projection of ions is obtained on the signal readout board,and the detector would get good spatial resolution.The spatial resolutions of the GEM neutron detector with the Al stopping layer are simulated and optimized based on Geant4 Garfield Interface.The spatial resolution of the detector is 0.76 mm and the thermal neutron detection efficiency is about 0.01%when the Al stopping layer is 3.0μm thick,the drift region is 2 mm thick,the strip pitch is 600μm,and the digital readout is employed.Thus,the GEM neutron detector with a simple detector structure and a fast readout mode is developed to obtain a high spatial resolution and high dynamic counting range.It could be used for the direct measurement of a high-flux neutron beam,such as Bragg transmission imaging,very small-angle scattering neutron detection and neutron beam diagnostic.展开更多
This work shows the results of a streamer discharge mode studies in various gas detectors developed up-to-date. The results are based on a new experimental data from high-speed thin-gap gas detector application develo...This work shows the results of a streamer discharge mode studies in various gas detectors developed up-to-date. The results are based on a new experimental data from high-speed thin-gap gas detector application developments as well as on basic knowledge of multi-wire devices operations.展开更多
In this paper several different working gas mixtures for GEM-TPC were evaluated based on a Garfield simulation. Among them, Ar：CH4：CF4=90：7：3 （named herein TU gas） was selected for a detailed study because of it...In this paper several different working gas mixtures for GEM-TPC were evaluated based on a Garfield simulation. Among them, Ar：CH4：CF4=90：7：3 （named herein TU gas） was selected for a detailed study because of its better performance. Some performances of drift velocity, transverse diffusion, spatial resolution and the effective number of electrons in various electric fields were obtained. The performance of a GEM-TPC prototype working in the TU gas was studied and compared with that in Ar：CH4=90：10 （P10 gas）.展开更多
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 co...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.展开更多
气体电子倍增器(GEM,Gas Electron Multiplier)是近些年发展的一种新的气体探测器,具有计数率和位置分辨率高等优点,在粒子物理和X光成像等领域有着广泛的应用前景,近些年来得到了很快的发展.该探测器发展的关键问题之一就是GEM膜结构...气体电子倍增器(GEM,Gas Electron Multiplier)是近些年发展的一种新的气体探测器,具有计数率和位置分辨率高等优点,在粒子物理和X光成像等领域有着广泛的应用前景,近些年来得到了很快的发展.该探测器发展的关键问题之一就是GEM膜结构的制造,该结构需要利用光刻等多项技术来完成,工艺复杂,研制困难.本文介绍了开发GEM膜结构的研究结果,通过干法和湿法腐蚀的研究和对比,优化出GEM膜结构制造的一种工艺过程,并利用该工艺成功完成了GEM膜结构的制造,为国内GEM气体探测器的研究和应用奠定了基础.展开更多
基金Supported by Fundamental Science on Nuclear Waste and Environmental Security Laboratory,Southwest University of Science and Technology. (Grant No.11zxnk03)
文摘A double thick GEM (THGEM) detector with thin THGEM foils and small holes was constructed. In order to optimize the operation parameters of the detector, a simulation study of the detector was carried out using ANSYS and Garfield program. Some important characteristics, including primary electron transparency, avalanche development and the secondary electron loss were calculated. Parameters, such as electric field and gas choice were optimized.
文摘Among the various micro-pattern gas detectors (MPGD) that are available, the gas electron multiplier (GEM) detector is an attractive gas detector that has been used in particle physics experiments. However, the GEM detector usually needs thousands of preamplifier units for its large number of micro-pattern readout strips or pads, which leads to considerable difficulties and complexities for front end electronics (FEE). Nowadays, by making use of complementary metal-oxide semiconductor (CMOS)-based application specific integrated circuit (ASIC), it is fea- sible to integrate hundreds of preamplifier units and other signal process circuits in a small-sized chip, which can be bound to the readout strips or pads of a micro-pattern particle detector (MPPD). Therefore, CMOS ASIC may provide an ideal solution to the readout problem of MPPD. In this article, a triple GEM detector is constructed and one of its readout strips is connected to a CMOS charge-sensitive preamplifier chip. The chip was exposed to an 55Fe source of 5.9 keV X-ray, and the amplitude spectrum of the chip was tested, and it was found that the energy resolution was approximately 27%, which indicates that the chip can be used in triple GEM detectors.
基金Supported by National Natural Science Foundation of China(11375219)CAS Center for Excellence in Particle Physics(CCEPP)
文摘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.
基金supported by the National Key R&D Program of China(Grant No.2017YFA0403702)the National Natural Science Foundation of China(Grant Nos.11574123,11775243,12175254,and U2032166)+1 种基金Youth Innovation Promotion Association CAS and Guangdong Basic and Applied Basic Research Foundation(Grant No.2019A1515110217)the Xie Jialin Foundation,China(Grant No.E1546FU2)。
文摘In recent years,gas electron multiplier(GEM)neutron detectors have been developing towards high spatial resolution and high dynamic counting range.We propose a novel concept of an Al stopping layer to enable the detector to achieve sub-millimeter(sub-mm)spatial resolution.The neutron conversion layer is coated with the Al stopping layer to limit the emission angle of ions into the drift region.The short track projection of ions is obtained on the signal readout board,and the detector would get good spatial resolution.The spatial resolutions of the GEM neutron detector with the Al stopping layer are simulated and optimized based on Geant4 Garfield Interface.The spatial resolution of the detector is 0.76 mm and the thermal neutron detection efficiency is about 0.01%when the Al stopping layer is 3.0μm thick,the drift region is 2 mm thick,the strip pitch is 600μm,and the digital readout is employed.Thus,the GEM neutron detector with a simple detector structure and a fast readout mode is developed to obtain a high spatial resolution and high dynamic counting range.It could be used for the direct measurement of a high-flux neutron beam,such as Bragg transmission imaging,very small-angle scattering neutron detection and neutron beam diagnostic.
文摘This work shows the results of a streamer discharge mode studies in various gas detectors developed up-to-date. The results are based on a new experimental data from high-speed thin-gap gas detector application developments as well as on basic knowledge of multi-wire devices operations.
基金Supported by CAS/SAFEA International Partnership Program for Creative Research Teams
文摘In this paper several different working gas mixtures for GEM-TPC were evaluated based on a Garfield simulation. Among them, Ar：CH4：CF4=90：7：3 （named herein TU gas） was selected for a detailed study because of its better performance. Some performances of drift velocity, transverse diffusion, spatial resolution and the effective number of electrons in various electric fields were obtained. The performance of a GEM-TPC prototype working in the TU gas was studied and compared with that in Ar：CH4=90：10 （P10 gas）.
基金Supported by Knowledge Innovation Program of Chinese Academy of Sciences
文摘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.
文摘气体电子倍增器(GEM,Gas Electron Multiplier)是近些年发展的一种新的气体探测器,具有计数率和位置分辨率高等优点,在粒子物理和X光成像等领域有着广泛的应用前景,近些年来得到了很快的发展.该探测器发展的关键问题之一就是GEM膜结构的制造,该结构需要利用光刻等多项技术来完成,工艺复杂,研制困难.本文介绍了开发GEM膜结构的研究结果,通过干法和湿法腐蚀的研究和对比,优化出GEM膜结构制造的一种工艺过程,并利用该工艺成功完成了GEM膜结构的制造,为国内GEM气体探测器的研究和应用奠定了基础.
