Testing of a triple gas electron multiplier （GEM） with pixel-pads is described. Images by scanning and suspending radioactive sources were obtained by using 96 channels digital data acquisition （DAQ） system which ...Testing of a triple gas electron multiplier （GEM） with pixel-pads is described. Images by scanning and suspending radioactive sources were obtained by using 96 channels digital data acquisition （DAQ） system which was composed of 96 8×8 mm2 pads and associated electronics channels.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
A kind of thick GEM-like gaseous electron multiplier （THGEM）, which is mechanically an expansion of the GEM with its various dimensions being enlarged, is studied. The leak current of THGEM plates is measured. The e...A kind of thick GEM-like gaseous electron multiplier （THGEM）, which is mechanically an expansion of the GEM with its various dimensions being enlarged, is studied. The leak current of THGEM plates is measured. The effective gain and energy resolution of a single THGEM are studied with a source of 55Fe, and the effective gain of the single THGEM versus the electric field strength in the induction region is investigated. The results show that the leak current of THGEM plates is less than 200 pA. In an atmospheric-pressure standard gas mixture, 8×103 effective gain and about 32% energy resolution can be reached for the single-THGEM detector.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
为实现探测器信号成像要求,研究一种气体电子倍增膜(gas electron multiplier,GEM)探测器的读出方法。采用印刷电路技术,将读出电极盘与场效应管的分立元件组合构成阵列,通过场效应管开关阵列,读出GEM探测器信号,并实现成像。实测表明:...为实现探测器信号成像要求,研究一种气体电子倍增膜(gas electron multiplier,GEM)探测器的读出方法。采用印刷电路技术,将读出电极盘与场效应管的分立元件组合构成阵列,通过场效应管开关阵列,读出GEM探测器信号,并实现成像。实测表明:该方法的动态范围(最大信号与噪声高宽的比值)可达7.3×104,积分非线性小于0.324%,灵敏度为2.55 V/nC,可实现30帧/s的实时成像。该方法具有制作工艺简单、参数可调、成本低等优点,为随后采用厚膜技术及薄膜场效应管技术读出GEM探测器提供了重要的设计依据。展开更多
An X-ray imaging device based on a triple-GEM （Gas Electron Multiplier） detector, a fast delay-line circuit with 700 MHz cut-off frequency and two dimensional readout strips with 150 μm width on the top and 250 μm...An X-ray imaging device based on a triple-GEM （Gas Electron Multiplier） detector, a fast delay-line circuit with 700 MHz cut-off frequency and two dimensional readout strips with 150 μm width on the top and 250 μm width on the bottom, is designed and tested. The localization information is derived from the propagation time of the induced signals on the readout strips. This device has a good spatial resolution of 150 μm and works stably at an intensity of 105 Hz/mm2 with 8 keV X-rays.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 time projection chamber （TPC） readout by gas electron multipliers （GEM） detector is a very promising candidate for the central tracking system of ILC （International Linear Collider）. A prototype is designed an...A time projection chamber （TPC） readout by gas electron multipliers （GEM） detector is a very promising candidate for the central tracking system of ILC （International Linear Collider）. A prototype is designed and set up in our lab and introduced here. The tests during and after the assembly prove that the prototype TPC has been constructed successfully. It is ready for further study.展开更多
A high-efficiency fast neutron detector prototype based on a triple Gas Electron Multiplier（GEM） detector, which, coupled with a novel multi-layered high-density polyethylene（HDPE） as a neutron-to-proton converter...A high-efficiency fast neutron detector prototype based on a triple Gas Electron Multiplier（GEM） detector, which, coupled with a novel multi-layered high-density polyethylene（HDPE） as a neutron-to-proton converter for improving the neutron detection efficiency, is introduced and tested with the Am-Be neutron source in the Institute of Modern Physics（IMP） at Lanzhou in the present work. First, the developed triple GEM detector is tested by measuring its effective gain and energy resolution with55 Fe X-ray source to ensure that it has a good performance.The effective gain and obtained energy resolution is 5.0×104and around 19.2%, respectively. Secondly, the novel multi-layered HDPE converter is coupled with the cathode of the triple GEM detector making it a high-efficiency fast neutron detector. Its effective neutron response is four times higher than that of the traditional single-layered conversion technique when the converter layer number is 38.展开更多
Gas electron multiplier （GEM） detectors have been used in cosmic muon scattering tomography and neutron imaging over the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × ...Gas electron multiplier （GEM） detectors have been used in cosmic muon scattering tomography and neutron imaging over the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × 10 cm is developed, and a method of discriminating between cosmic muons and X-rays based on rise time is tested. The energy resolution of the GEM detector is tested by 55Fe ray source to prove the GEM detector has a good performance. Analysis of the complete signal-cycles allows us to get the rise time and pulse heights. The experiment result indicates that cosmic muons and X-rays can be discriminated with an appropriate rise time threshold.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
文摘Testing of a triple gas electron multiplier （GEM） with pixel-pads is described. Images by scanning and suspending radioactive sources were obtained by using 96 channels digital data acquisition （DAQ） system which was composed of 96 8×8 mm2 pads and associated electronics channels.
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.
基金Supported by National Natural Science Foundation of China (10675146, 10775151, 10775181)
文摘A kind of thick GEM-like gaseous electron multiplier （THGEM）, which is mechanically an expansion of the GEM with its various dimensions being enlarged, is studied. The leak current of THGEM plates is measured. The effective gain and energy resolution of a single THGEM are studied with a source of 55Fe, and the effective gain of the single THGEM versus the electric field strength in the induction region is investigated. The results show that the leak current of THGEM plates is less than 200 pA. In an atmospheric-pressure standard gas mixture, 8×103 effective gain and about 32% energy resolution can be reached for the single-THGEM detector.
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.
文摘为实现探测器信号成像要求,研究一种气体电子倍增膜(gas electron multiplier,GEM)探测器的读出方法。采用印刷电路技术,将读出电极盘与场效应管的分立元件组合构成阵列,通过场效应管开关阵列,读出GEM探测器信号,并实现成像。实测表明:该方法的动态范围(最大信号与噪声高宽的比值)可达7.3×104,积分非线性小于0.324%,灵敏度为2.55 V/nC,可实现30帧/s的实时成像。该方法具有制作工艺简单、参数可调、成本低等优点,为随后采用厚膜技术及薄膜场效应管技术读出GEM探测器提供了重要的设计依据。
基金Supported by National Natural Science Foundation of China (10575101)
文摘An X-ray imaging device based on a triple-GEM （Gas Electron Multiplier） detector, a fast delay-line circuit with 700 MHz cut-off frequency and two dimensional readout strips with 150 μm width on the top and 250 μm width on the bottom, is designed and tested. The localization information is derived from the propagation time of the induced signals on the readout strips. This device has a good spatial resolution of 150 μm and works stably at an intensity of 105 Hz/mm2 with 8 keV X-rays.
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%.
基金Supported by National Natural Science Foundation of China(10575063)
文摘A time projection chamber （TPC） readout by gas electron multipliers （GEM） detector is a very promising candidate for the central tracking system of ILC （International Linear Collider）. A prototype is designed and set up in our lab and introduced here. The tests during and after the assembly prove that the prototype TPC has been constructed successfully. It is ready for further study.
基金Supported by National Natural Science Foundation of China(11135002,11305232,11175076)
文摘A high-efficiency fast neutron detector prototype based on a triple Gas Electron Multiplier（GEM） detector, which, coupled with a novel multi-layered high-density polyethylene（HDPE） as a neutron-to-proton converter for improving the neutron detection efficiency, is introduced and tested with the Am-Be neutron source in the Institute of Modern Physics（IMP） at Lanzhou in the present work. First, the developed triple GEM detector is tested by measuring its effective gain and energy resolution with55 Fe X-ray source to ensure that it has a good performance.The effective gain and obtained energy resolution is 5.0×104and around 19.2%, respectively. Secondly, the novel multi-layered HDPE converter is coupled with the cathode of the triple GEM detector making it a high-efficiency fast neutron detector. Its effective neutron response is four times higher than that of the traditional single-layered conversion technique when the converter layer number is 38.
基金Supported by National Natural Science Foundation of China(11135002,11275235,11405077,11575073)
文摘Gas electron multiplier （GEM） detectors have been used in cosmic muon scattering tomography and neutron imaging over the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × 10 cm is developed, and a method of discriminating between cosmic muons and X-rays based on rise time is tested. The energy resolution of the GEM detector is tested by 55Fe ray source to prove the GEM detector has a good performance. Analysis of the complete signal-cycles allows us to get the rise time and pulse heights. The experiment result indicates that cosmic muons and X-rays can be discriminated with an appropriate rise time threshold.
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.
