A normal-pressure MWPC detector for position measurement of intermediate and high energy radioactive ionsat RIBLL2 has been fabricated, which has a sensitive area of 75 mm100 mm and contains of three wire planes.Fig....A normal-pressure MWPC detector for position measurement of intermediate and high energy radioactive ionsat RIBLL2 has been fabricated, which has a sensitive area of 75 mm100 mm and contains of three wire planes.Fig. 1 shows the layout of the MWPC wire planes.The anode plane is sandwiched between two cathodeplanes, and the anode-cathode spacing is 4 mm. Theanode plane consisted of 15 m gold-plated tungstenwires with a pitch of 2 mm. The cathode planes Xand Y , made of 60 m stainless steel wires with apitch of 0.5 mm, and every adjacent four wires are sol-dered together to form one readout strip of 2 mm inwidth. The wire directions in X and Y are orthogonalto each other, the wire direction in anode is parallel tothe wire direction in Y .展开更多
For MWPCs used for X-ray position detection, simulation studies of the anode wire modulation effect of the detector were carried out using the Garfield program. Different gas mixtures were used as the working gas in t...For MWPCs used for X-ray position detection, simulation studies of the anode wire modulation effect of the detector were carried out using the Garfield program. Different gas mixtures were used as the working gas in the simulation, so as to obtain the influence of the X-ray cross section and electron diffusion coefficient of the working gases on the anode wire modulation effect of an MWPC with anode wire spacing of 2 mm. Results show that, though a working gas with higher X-ray cross section implies a larger average drift distance for the ionized electrons, such gas mixtures are of little use in improving the anode wire modulation effect of MWPCs. It is found that the transverse electron diffusion coefficient is the determining factor for the extent of the anode wire modulation effect in the detector.展开更多
A normal pressure MWPC for beam diagnostics at RIBLL2 has been developed, wmcn has a sensluve area of 80 mm×80 mm and consists of three-layer wire planes. The anode plane is designed with a wider frame to reduce ...A normal pressure MWPC for beam diagnostics at RIBLL2 has been developed, wmcn has a sensluve area of 80 mm×80 mm and consists of three-layer wire planes. The anode plane is designed with a wider frame to reduce the discharge and without using protection wires. The detector has been tested with a 55Fe X-ray source and a 200 MeV/u ^12C beam from CSRm. A position resdution better than 250 μm along the anode wires and a detection efficiency higher than 90% have been achieved.展开更多
We have developed a large area multi-wire proportional counter （MWPC） as a standard for the measurement of alpha and beta surface emission rate at the Shanghai Institute of Measurement and Testing Technology （SIMT...We have developed a large area multi-wire proportional counter （MWPC） as a standard for the measurement of alpha and beta surface emission rate at the Shanghai Institute of Measurement and Testing Technology （SIMT）. To shorten the preparation time for chamber gas refilling, a self-designed gas control unit was adopted. Various characteristics of the system have been studied. The uncertainties were analysed. Three certified alpha plane sources （Am-241） and six certified beta plane sources （T1-204 and Sr-90/Y-90） were measured by this system, The results show excellent agreement with the surface emission rate reported by the National Institute of Measuring, China （NIM） that En values of all measured sources are within ±1.展开更多
In a multi-wire proportional chamber detector（MWPC）, the anode and signal wires must maintain suitable tension, which is very important for the detector＇s stable and accurate performance. As a result, wire tension ...In a multi-wire proportional chamber detector（MWPC）, the anode and signal wires must maintain suitable tension, which is very important for the detector＇s stable and accurate performance. As a result, wire tension control and measurement is essential in MWPC construction. A high pressure3 He MWPC detector is to be used as the thermal neutron detector of the multi-functional reflectometer at China Spallation Neutron Source, and in the construction of the detector, we have developed a wire tension measurement system. This system is accurate,portable and time-saving. With it, the wire tension on an anode wire plane has been tested. The measurement results show that the wire tension control techniques used in detector manufacture are reliable.展开更多
Two couples of low pressure multi-wire proportional chambers （MWPC） were located in the target chamber to detect fission fragments in a hypernuclei producing experiment at Thomas Jefferson National Laboratory （Jlab...Two couples of low pressure multi-wire proportional chambers （MWPC） were located in the target chamber to detect fission fragments in a hypernuclei producing experiment at Thomas Jefferson National Laboratory （Jlab）. In the experiment, a continuous wave （CW） electron beam was applied to form hypernuclei by electromagnetic interaction. In the target chamber, the high energy （1.853 GeV） and high intensity （500 nA） primary electron beam caused a high particle background, which influenced the detection of the fission fragments. This report described the design of the MWPCs and studied the fission-fragment detecting performance of them under such a high background. The efficiency of the MWPCs was given with the help of a high resolution kaon spectrometer. At the same time, the background particles were discussed with a Monte Carlo code based on GEANT4.展开更多
Purpose Boron-lined gas detectors are prospective alternatives to helium-3-based neutron detectors.For boron-lined multiwire proportional chamber(MWPC)with neutron grazing incident angle geometry,high neutron detectio...Purpose Boron-lined gas detectors are prospective alternatives to helium-3-based neutron detectors.For boron-lined multiwire proportional chamber(MWPC)with neutron grazing incident angle geometry,high neutron detection efficiency and 3D position sensitive can be realized.In this paper,a multi-layer boron-lined MWPC was studied.Methods Influences of the boron coating thickness,coating layer numbers and neutron incident angle on the neutron detection efficiency were studied and optimized with Geant4 simulation.The output signal properties including induced signal width on the readout plane,the time resolution and gas gain uniformity of the detector were studied with Garfield program.Results and conclusion The results show that the neutron detection efficiency can be significantly increased by using neutron grazing incident geometry.For 4 layers of 10B4Cwith thickness of 1μm,the neutron detection efficiency can reach to 54.56%,49.17%and 44.36%when neutron incident angle is 6°,8°and 10°,respectively.For detector with curved geometry,the gas gain is nonuniform among the anode wires,and using separate high voltage for each anode wire or wires group can effectively reduce the nonuniform of the gas gain.The results of this work can be used to optimize the detector design.展开更多
文摘A normal-pressure MWPC detector for position measurement of intermediate and high energy radioactive ionsat RIBLL2 has been fabricated, which has a sensitive area of 75 mm100 mm and contains of three wire planes.Fig. 1 shows the layout of the MWPC wire planes.The anode plane is sandwiched between two cathodeplanes, and the anode-cathode spacing is 4 mm. Theanode plane consisted of 15 m gold-plated tungstenwires with a pitch of 2 mm. The cathode planes Xand Y , made of 60 m stainless steel wires with apitch of 0.5 mm, and every adjacent four wires are sol-dered together to form one readout strip of 2 mm inwidth. The wire directions in X and Y are orthogonalto each other, the wire direction in anode is parallel tothe wire direction in Y .
基金Supported by Scientific Research Fund of Sichuan Provincial Education Department(11ZA140)
文摘For MWPCs used for X-ray position detection, simulation studies of the anode wire modulation effect of the detector were carried out using the Garfield program. Different gas mixtures were used as the working gas in the simulation, so as to obtain the influence of the X-ray cross section and electron diffusion coefficient of the working gases on the anode wire modulation effect of an MWPC with anode wire spacing of 2 mm. Results show that, though a working gas with higher X-ray cross section implies a larger average drift distance for the ionized electrons, such gas mixtures are of little use in improving the anode wire modulation effect of MWPCs. It is found that the transverse electron diffusion coefficient is the determining factor for the extent of the anode wire modulation effect in the detector.
基金Supported by National Natural Science Foundation of China(11079044)
文摘A normal pressure MWPC for beam diagnostics at RIBLL2 has been developed, wmcn has a sensluve area of 80 mm×80 mm and consists of three-layer wire planes. The anode plane is designed with a wider frame to reduce the discharge and without using protection wires. The detector has been tested with a 55Fe X-ray source and a 200 MeV/u ^12C beam from CSRm. A position resdution better than 250 μm along the anode wires and a detection efficiency higher than 90% have been achieved.
基金Supported by National Natural Science Foundation of China(41204133)
文摘We have developed a large area multi-wire proportional counter （MWPC） as a standard for the measurement of alpha and beta surface emission rate at the Shanghai Institute of Measurement and Testing Technology （SIMT）. To shorten the preparation time for chamber gas refilling, a self-designed gas control unit was adopted. Various characteristics of the system have been studied. The uncertainties were analysed. Three certified alpha plane sources （Am-241） and six certified beta plane sources （T1-204 and Sr-90/Y-90） were measured by this system, The results show excellent agreement with the surface emission rate reported by the National Institute of Measuring, China （NIM） that En values of all measured sources are within ±1.
基金Supported by National Natural Science Foundation of China(A050506)State Key Laboratory of Particle Detection and ElectronicsKey Laboratory of China Academy of Engineering Physics(Y490KF40HD)
文摘In a multi-wire proportional chamber detector（MWPC）, the anode and signal wires must maintain suitable tension, which is very important for the detector＇s stable and accurate performance. As a result, wire tension control and measurement is essential in MWPC construction. A high pressure3 He MWPC detector is to be used as the thermal neutron detector of the multi-functional reflectometer at China Spallation Neutron Source, and in the construction of the detector, we have developed a wire tension measurement system. This system is accurate,portable and time-saving. With it, the wire tension on an anode wire plane has been tested. The measurement results show that the wire tension control techniques used in detector manufacture are reliable.
基金Supported by Fundamental Research Funds for Central Universities (HEUCF101501)Fundamental Research Funds of Harbin Engineering University (002150260713)National Natural Science Foundation of China (10575046)
文摘Two couples of low pressure multi-wire proportional chambers （MWPC） were located in the target chamber to detect fission fragments in a hypernuclei producing experiment at Thomas Jefferson National Laboratory （Jlab）. In the experiment, a continuous wave （CW） electron beam was applied to form hypernuclei by electromagnetic interaction. In the target chamber, the high energy （1.853 GeV） and high intensity （500 nA） primary electron beam caused a high particle background, which influenced the detection of the fission fragments. This report described the design of the MWPCs and studied the fission-fragment detecting performance of them under such a high background. The efficiency of the MWPCs was given with the help of a high resolution kaon spectrometer. At the same time, the background particles were discussed with a Monte Carlo code based on GEANT4.
基金the National Natural Science Foundation of China(Grant No.11505147)the State Key Laboratory of Particle Detection and Electronics(SKLPDE-KF-202009)Fundamental Science on NuclearWastes and Environmental Safety Laboratory(16kfhk05).
文摘Purpose Boron-lined gas detectors are prospective alternatives to helium-3-based neutron detectors.For boron-lined multiwire proportional chamber(MWPC)with neutron grazing incident angle geometry,high neutron detection efficiency and 3D position sensitive can be realized.In this paper,a multi-layer boron-lined MWPC was studied.Methods Influences of the boron coating thickness,coating layer numbers and neutron incident angle on the neutron detection efficiency were studied and optimized with Geant4 simulation.The output signal properties including induced signal width on the readout plane,the time resolution and gas gain uniformity of the detector were studied with Garfield program.Results and conclusion The results show that the neutron detection efficiency can be significantly increased by using neutron grazing incident geometry.For 4 layers of 10B4Cwith thickness of 1μm,the neutron detection efficiency can reach to 54.56%,49.17%and 44.36%when neutron incident angle is 6°,8°and 10°,respectively.For detector with curved geometry,the gas gain is nonuniform among the anode wires,and using separate high voltage for each anode wire or wires group can effectively reduce the nonuniform of the gas gain.The results of this work can be used to optimize the detector design.
