本文采用了自主研发的THGEM探测器,其具有双膜结构,64路直流读出电子学等特点。采用该THGEM探测器在K荧光装置上,开展了对15~70 ke V内多能量点X射线的探测实验工作;结果显示该THGEM探测器对宽能区、高注量(剂量当量)的X射线具有良好线...本文采用了自主研发的THGEM探测器,其具有双膜结构,64路直流读出电子学等特点。采用该THGEM探测器在K荧光装置上,开展了对15~70 ke V内多能量点X射线的探测实验工作;结果显示该THGEM探测器对宽能区、高注量(剂量当量)的X射线具有良好线性响应,并分析了影响探测效率的因素。展开更多
In cases of high radiation emergencies,we propose a surface contamination monitor(SCM)that can quickly measure and pinpoint the contamination distribution in the affected population.Thick gaseous electron multiplier(T...In cases of high radiation emergencies,we propose a surface contamination monitor(SCM)that can quickly measure and pinpoint the contamination distribution in the affected population.Thick gaseous electron multiplier(THGEM)has several advantages,including fast response time and good spatial resolution.Based on new THGEMs,a two-dimensional imaging detector was developed for alpha detection,with a position resolution greater than 3 mm.The detector design and test results are described in this paper.Fast radiation imaging SCMs,with a 40mm×40 mm sensitive area,are currently under development.展开更多
Thick gas electron multipliers (THGEMs) are new types of gas detectors with merits such as a high counting rate,anti-radiation,high gain,robustness and relatively low cost.We establish an up-down THGEM detector hodosc...Thick gas electron multipliers (THGEMs) are new types of gas detectors with merits such as a high counting rate,anti-radiation,high gain,robustness and relatively low cost.We establish an up-down THGEM detector hodoscope system for detecting and displaying muon tracks.Muon tracks can be well observed with the detectors and the present study lays an important technological foundation for the domestic and mass production of THGEMs.展开更多
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
新型多层厚型气体电子倍增器(Multi-layers THick Gas Electron Multiplier,M-THGEM)和传统THGEM(厚型气体电子倍增器)相比,具有连续的雪崩区,能够在低气压和低电压下都有较高增益,结构更紧凑,易于大面积制作等优势。对M-THGEM探测器的...新型多层厚型气体电子倍增器(Multi-layers THick Gas Electron Multiplier,M-THGEM)和传统THGEM(厚型气体电子倍增器)相比,具有连续的雪崩区,能够在低气压和低电压下都有较高增益,结构更紧凑,易于大面积制作等优势。对M-THGEM探测器的工作原理及性能进行了模拟研究,首先通过有限元(ANSYS)软件对二层与三层结构的M-THGEM进行了建模,对电场和电势分布分别进行了模拟计算;再利用Garfield++程序包对M-THGEM探测器在不同低气压和不同工作电压下的增益、感生信号、正离子反馈率等性能进行了研究。模拟结果表明,三层结构M-THGEM在低气压(200 Torr)、纯He气体条件下,能够获得较稳定的增益(10~5),输出信号的宽度在12 ns左右;同时,为降低正离子反馈率,本工作提出并研究了一种非对称的电压施加方式,结果表明,这种施加方式能有效降低正离子的反馈率。展开更多
In this paper, the performance of a type of domestic THGEM （THick Gaseous Electron Multiplier） working in Ar/CO2 mixtures is reported in detail. This kind of single THGEM can provide a gain range from 100 to 1000, w...In this paper, the performance of a type of domestic THGEM （THick Gaseous Electron Multiplier） working in Ar/CO2 mixtures is reported in detail. This kind of single THGEM can provide a gain range from 100 to 1000, which is very suitable for application in neutron detection. In order to study its basic characteristics as a reference for the development of a THGEM based neutron detector, the counting rate plateau, the energy resolution and the gain of the THGEM have been measured in different Ar/CO2 mixtures with a variety of electrical fields. For the Ar/CO2（90%/10%） gas mixture, a wide counting rate plateau is achieved from 720 V to 770 V, with a plateau slope of 2.4%/100 V, and an excellent energy resolution of about 22% is obtained at the 5.9 keV full energy peak of the 55Fe X-ray source.展开更多
GPM based on THGEM has shown its competitive strength compared to the conventional PMT, espe- cially in the low background research such as dark matter detection. A kind of THGEM made from PTFE, named PTFE-THGEM, is d...GPM based on THGEM has shown its competitive strength compared to the conventional PMT, espe- cially in the low background research such as dark matter detection. A kind of THGEM made from PTFE, named PTFE-THGEM, is developed for the GPM to be used in CDEX. The PTFE has a lot of advantages especially its low level radioactivity. The PTFE-THGEM was tested at room and cryogenic temperature. It has a high gain in different gases and shows good stability at room temperature. The gain of a single PTFE-THGEM reached 112 at 117 K. The penning effect is also discussed in this paper to explain the ＂abnormal＂ phenomena of the gain in different gases.展开更多
The THGEM detector without and with a CsI has been tested successfully. The optimal parameters of THGEM have been determined from eight samples. The UV photoelectric effect of the CsI photocathode is observed. The cha...The THGEM detector without and with a CsI has been tested successfully. The optimal parameters of THGEM have been determined from eight samples. The UV photoelectric effect of the CsI photocathode is observed. The changing tendency related to the extraction efficiency （εextr） versus the extraction electric field is measured, and several electric fields influencing the anode current are adjusted to adapt to the THGEM detector with a reflective CsI photocathode.展开更多
With new generation neutron sources, traditional neutron detectors cannot satisfy the demands of the applications, especially under high flux. Furthermore, facing the global crisis in 3He gas supply, research on new t...With new generation neutron sources, traditional neutron detectors cannot satisfy the demands of the applications, especially under high flux. Furthermore, facing the global crisis in 3He gas supply, research on new types of neutron detector as an alternative to 3He is a research hotspot in the field of particle detection. GEM （Gaseous Electron Multiplier） neutron detectors have high counting rate, good spatial and time resolution, and could be one future direction of the development of neutron detectors. In this paper, the physical process of neutron detection is simulated with Geant4 code, studying the relations between thermal conversion efficiency, boron thickness and number of boron layers. Due to the special characteristics of neutron detection, we have developed a novel type of special ceramic nTHGEM （neutron THick GEM） for neutron detection. The performance of the nTHGEM working in different Ar/CO2 mixtures is presented, including measurements of the gain and the count rate plateau using a copper target X-ray source. A detector with a single nTHGEM has been tested for 2-D imaging using a 252Cf neutron source. The key parameters of the performance of the nTHGEM detector have been obtained, providing necessary experimental data as a reference for further research on this detector.展开更多
The gas gain and energy resolution of single and double THGEM detectors （5 cm×5 cm effective area） with mini-rims （rim less than 10 um） were studied. The maximum gain was found to reach 5×103 and 2 ×...The gas gain and energy resolution of single and double THGEM detectors （5 cm×5 cm effective area） with mini-rims （rim less than 10 um） were studied. The maximum gain was found to reach 5×103 and 2 × 105 for single and double THGEMs respectively, while the energy resolution for 5.9 keV X-rays varied from 18% to 28% for both single and double THGEM detectors of different hole sizes and thicknesses. Different combinations were also investigated of noble gases （argon, neon） mixed with a quantity of other gases （isobutane, methane） at atmospheric pressure.展开更多
A new thermal neutron detector with a domestically produced THGEM （Thick Gas Electron Multiplier） was developed as an alternative to 3He to meet the needs of the next generation of neutron facilities. One type of Au...A new thermal neutron detector with a domestically produced THGEM （Thick Gas Electron Multiplier） was developed as an alternative to 3He to meet the needs of the next generation of neutron facilities. One type of Au-coated THGEM was designed specifically for neutron detection. A detector prototype has been developed and the preliminary experimental tests are presented, including the performance of the Au-coated THGEM working in At/CO2 gas mixtures and the neutron imaging test with 252 Cf source, which can provide the reference for experimental data for research in the future.展开更多
Introduction Boron-coated micro-pattern gaseous detectors,such as gaseous electron multiplier(GEM),are widely studied as the neutron detectors.The existing solution to improve the neutron detection efficiency(NDE)is t...Introduction Boron-coated micro-pattern gaseous detectors,such as gaseous electron multiplier(GEM),are widely studied as the neutron detectors.The existing solution to improve the neutron detection efficiency(NDE)is to coat the boron on the surfaces of the cascade GEM films.So the GEM films themselves will be affected by the complicated coating process and the boron layers,and the 10B material will be wasted once the GEM films are damaged.Since the neutron conversion and the electron multiplication regions are not separated,the final gains of different layer ionized electrons are very difficult to control and keep consistent.Materials and methods A new neutron detector based on the ceramic thick GEM(THGEM)was proposed.The boron-coated cathode and multilayer meshes were used as the neutron conversion region and separated from the electron multiplication region consisting of only one THGEM film.The sawtooth surface treatment and the double-sided readout method were applied to improve neutron conversion efficiency(NCE).The neutron conversion and the electron collection efficiencies were simulated and studied based on the new structure.The prototype detector was test by using a ^(252)Cf neutron source.Results The simulation results show that the cascade boron-coated meshes have good neutron conversion and electron collection efficiencies,and the double-sided readout and sawtooth structure can greatly increase the NCE.The neutron test results show that the detection efficiency of the double-sided readout is 1.6 times higher than that of the common single-sided readout.These indicate that the new detector has high neutron conversion and detection efficiencies and is promising for practical applications.展开更多
A sealed high gas pressure detector working in pure argon is assembled.It consists of a 5 cm × 5 cm PCB THGEM（THick Gaseous Electron Multiplier）.The detector structure and experimental setup are described.The p...A sealed high gas pressure detector working in pure argon is assembled.It consists of a 5 cm × 5 cm PCB THGEM（THick Gaseous Electron Multiplier）.The detector structure and experimental setup are described.The performance under high pressure（2 atm） is examined,selecting optimal voltages for the ionization region and induction region.The dependence of the shape of alpha particle spectra measured with relative gas gain on gas pressure（1.3-2.0 atm） has been studied.Eight data sets of relative gas gain versus working voltage of THGEM,expressed by weighting field E/P,are normalized,consistent with theory.The results show that the air tightness of the chamber is good,measured by a sensitive barometer and checked with gas gain.The experimental results are compared with Monte Carlo simulation of energy deposition without gas gain involved.展开更多
基金supported by the China Institute of Atomic Energy and University of Chinese Academy of SciencesNational Natural Science Foundation of China(Nos.11575193 and U1732266)+2 种基金Key Research Program of Frontier Sciences,CAS(No.QYZDB-SSWSLH039)the Youth Innovation Promotion Association of CAS(No.2016153)the Natural Science Key Foundation of Guangxi(No.2015GXNSFDA139002)
文摘In cases of high radiation emergencies,we propose a surface contamination monitor(SCM)that can quickly measure and pinpoint the contamination distribution in the affected population.Thick gaseous electron multiplier(THGEM)has several advantages,including fast response time and good spatial resolution.Based on new THGEMs,a two-dimensional imaging detector was developed for alpha detection,with a position resolution greater than 3 mm.The detector design and test results are described in this paper.Fast radiation imaging SCMs,with a 40mm×40 mm sensitive area,are currently under development.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10775181 and 10775151.
文摘Thick gas electron multipliers (THGEMs) are new types of gas detectors with merits such as a high counting rate,anti-radiation,high gain,robustness and relatively low cost.We establish an up-down THGEM detector hodoscope system for detecting and displaying muon tracks.Muon tracks can be well observed with the detectors and the present study lays an important technological foundation for the domestic and mass production of THGEMs.
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.
文摘新型多层厚型气体电子倍增器(Multi-layers THick Gas Electron Multiplier,M-THGEM)和传统THGEM(厚型气体电子倍增器)相比,具有连续的雪崩区,能够在低气压和低电压下都有较高增益,结构更紧凑,易于大面积制作等优势。对M-THGEM探测器的工作原理及性能进行了模拟研究,首先通过有限元(ANSYS)软件对二层与三层结构的M-THGEM进行了建模,对电场和电势分布分别进行了模拟计算;再利用Garfield++程序包对M-THGEM探测器在不同低气压和不同工作电压下的增益、感生信号、正离子反馈率等性能进行了研究。模拟结果表明,三层结构M-THGEM在低气压(200 Torr)、纯He气体条件下,能够获得较稳定的增益(10~5),输出信号的宽度在12 ns左右;同时,为降低正离子反馈率,本工作提出并研究了一种非对称的电压施加方式,结果表明,这种施加方式能有效降低正离子的反馈率。
基金Supported by National Natural Science Foundation of China(11127508,11175199)NPL,CAEP(Project 2013DB06)
文摘In this paper, the performance of a type of domestic THGEM （THick Gaseous Electron Multiplier） working in Ar/CO2 mixtures is reported in detail. This kind of single THGEM can provide a gain range from 100 to 1000, which is very suitable for application in neutron detection. In order to study its basic characteristics as a reference for the development of a THGEM based neutron detector, the counting rate plateau, the energy resolution and the gain of the THGEM have been measured in different Ar/CO2 mixtures with a variety of electrical fields. For the Ar/CO2（90%/10%） gas mixture, a wide counting rate plateau is achieved from 720 V to 770 V, with a plateau slope of 2.4%/100 V, and an excellent energy resolution of about 22% is obtained at the 5.9 keV full energy peak of the 55Fe X-ray source.
文摘GPM based on THGEM has shown its competitive strength compared to the conventional PMT, espe- cially in the low background research such as dark matter detection. A kind of THGEM made from PTFE, named PTFE-THGEM, is developed for the GPM to be used in CDEX. The PTFE has a lot of advantages especially its low level radioactivity. The PTFE-THGEM was tested at room and cryogenic temperature. It has a high gain in different gases and shows good stability at room temperature. The gain of a single PTFE-THGEM reached 112 at 117 K. The penning effect is also discussed in this paper to explain the ＂abnormal＂ phenomena of the gain in different gases.
基金Supported by National Natural Science Foundation of China (10775181,10775151)A. Breskin of Weizmann Inst., P. Picchi and A.Braem of CERN for their friendly discussions andkind supportthe NNSF of China for support of this work
文摘The THGEM detector without and with a CsI has been tested successfully. The optimal parameters of THGEM have been determined from eight samples. The UV photoelectric effect of the CsI photocathode is observed. The changing tendency related to the extraction efficiency （εextr） versus the extraction electric field is measured, and several electric fields influencing the anode current are adjusted to adapt to the THGEM detector with a reflective CsI photocathode.
基金Supported by National Natural Science Foundation of China(11127508,11175199,11205253,11405191)Key Laboratory of Neutron Physics,CAEP(2013DB06,2013BB04)and CAS(YZ201512)
文摘With new generation neutron sources, traditional neutron detectors cannot satisfy the demands of the applications, especially under high flux. Furthermore, facing the global crisis in 3He gas supply, research on new types of neutron detector as an alternative to 3He is a research hotspot in the field of particle detection. GEM （Gaseous Electron Multiplier） neutron detectors have high counting rate, good spatial and time resolution, and could be one future direction of the development of neutron detectors. In this paper, the physical process of neutron detection is simulated with Geant4 code, studying the relations between thermal conversion efficiency, boron thickness and number of boron layers. Due to the special characteristics of neutron detection, we have developed a novel type of special ceramic nTHGEM （neutron THick GEM） for neutron detection. The performance of the nTHGEM working in different Ar/CO2 mixtures is presented, including measurements of the gain and the count rate plateau using a copper target X-ray source. A detector with a single nTHGEM has been tested for 2-D imaging using a 252Cf neutron source. The key parameters of the performance of the nTHGEM detector have been obtained, providing necessary experimental data as a reference for further research on this detector.
基金Supported by Youth Fund of Institute of High Energy PhysicsChinese Academy of Sciences and National Natural Science Foundation of China (10775151)
文摘The gas gain and energy resolution of single and double THGEM detectors （5 cm×5 cm effective area） with mini-rims （rim less than 10 um） were studied. The maximum gain was found to reach 5×103 and 2 × 105 for single and double THGEMs respectively, while the energy resolution for 5.9 keV X-rays varied from 18% to 28% for both single and double THGEM detectors of different hole sizes and thicknesses. Different combinations were also investigated of noble gases （argon, neon） mixed with a quantity of other gases （isobutane, methane） at atmospheric pressure.
基金Supported by National Natural Science Foundation of China(11127508,11175199)NPL,CAEP(2013DB06)State Key Laboratory of particle Detection and Electronics(H9294206TD)
文摘A new thermal neutron detector with a domestically produced THGEM （Thick Gas Electron Multiplier） was developed as an alternative to 3He to meet the needs of the next generation of neutron facilities. One type of Au-coated THGEM was designed specifically for neutron detection. A detector prototype has been developed and the preliminary experimental tests are presented, including the performance of the Au-coated THGEM working in At/CO2 gas mixtures and the neutron imaging test with 252 Cf source, which can provide the reference for experimental data for research in the future.
基金This work is supported by the State Key Laboratory of Particle Detection and Electronics,H9294206TD.
文摘Introduction Boron-coated micro-pattern gaseous detectors,such as gaseous electron multiplier(GEM),are widely studied as the neutron detectors.The existing solution to improve the neutron detection efficiency(NDE)is to coat the boron on the surfaces of the cascade GEM films.So the GEM films themselves will be affected by the complicated coating process and the boron layers,and the 10B material will be wasted once the GEM films are damaged.Since the neutron conversion and the electron multiplication regions are not separated,the final gains of different layer ionized electrons are very difficult to control and keep consistent.Materials and methods A new neutron detector based on the ceramic thick GEM(THGEM)was proposed.The boron-coated cathode and multilayer meshes were used as the neutron conversion region and separated from the electron multiplication region consisting of only one THGEM film.The sawtooth surface treatment and the double-sided readout method were applied to improve neutron conversion efficiency(NCE).The neutron conversion and the electron collection efficiencies were simulated and studied based on the new structure.The prototype detector was test by using a ^(252)Cf neutron source.Results The simulation results show that the cascade boron-coated meshes have good neutron conversion and electron collection efficiencies,and the double-sided readout and sawtooth structure can greatly increase the NCE.The neutron test results show that the detection efficiency of the double-sided readout is 1.6 times higher than that of the common single-sided readout.These indicate that the new detector has high neutron conversion and detection efficiencies and is promising for practical applications.
基金Supported by National Natural Science Foundation of China(11575193,11205240,11265003,U1431109)
文摘A sealed high gas pressure detector working in pure argon is assembled.It consists of a 5 cm × 5 cm PCB THGEM（THick Gaseous Electron Multiplier）.The detector structure and experimental setup are described.The performance under high pressure（2 atm） is examined,selecting optimal voltages for the ionization region and induction region.The dependence of the shape of alpha particle spectra measured with relative gas gain on gas pressure（1.3-2.0 atm） has been studied.Eight data sets of relative gas gain versus working voltage of THGEM,expressed by weighting field E/P,are normalized,consistent with theory.The results show that the air tightness of the chamber is good,measured by a sensitive barometer and checked with gas gain.The experimental results are compared with Monte Carlo simulation of energy deposition without gas gain involved.
