Purpose The purpose of this study is to develop a high transmittance,sealed neutron beam monitor,which can be used in vacuum environment such as the Small-Angle Neutron Scattering spectrometer at China Spallation Neut...Purpose The purpose of this study is to develop a high transmittance,sealed neutron beam monitor,which can be used in vacuum environment such as the Small-Angle Neutron Scattering spectrometer at China Spallation Neutron Source(CSNS).Methods Boron-lined multi-wire proportion chamber was adopted to measure the neutron counting rate.A small anode spacing of 4 mm was chosen to realize high counting rate ability of the monitor.GEANT4 simulation was first carried out to optimize the cell structure of the detector.The relationship between the neutron detection and the boron layer thickness,the scattering rate of the detector body to the neutron beam,etc.were obtained.Then the monitor was manufactured and tested with Am-241 source.Finally,neutron beam tests were conducted at the 20th beamline(BL20)of the CSNS,and the response of the monitor to the neutron beam was obtained.Results and conclusion A monitor with detection efficiency of 0.15%@1.8Åand sensitive area of 100×100 mm^(2) was constructed.The monitor maintained good performances for over 6 months and can obtain neutron beam parameters including neutron counting rate and neutron time-of-flight spectrum,etc.Then the neutron beam intensity,neutron wavelength spectrum,etc.can be provided.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
基金supported by the National Natural Science Foundation of China(Grant No.12275181,12227810)Guangdong Major Project of Basic and Applied Basic Research(Grant No.2023B0303000003)+2 种基金Natural Science Foundation of Top Talent SZTU(GDRC202205)the Guangdong-HongKong-Macao Joint Laboratory for Neutron Scattering Science and TechnologyGuangdong Provincial Key Laboratory of Advanced Particle Detection Technology.
文摘Purpose The purpose of this study is to develop a high transmittance,sealed neutron beam monitor,which can be used in vacuum environment such as the Small-Angle Neutron Scattering spectrometer at China Spallation Neutron Source(CSNS).Methods Boron-lined multi-wire proportion chamber was adopted to measure the neutron counting rate.A small anode spacing of 4 mm was chosen to realize high counting rate ability of the monitor.GEANT4 simulation was first carried out to optimize the cell structure of the detector.The relationship between the neutron detection and the boron layer thickness,the scattering rate of the detector body to the neutron beam,etc.were obtained.Then the monitor was manufactured and tested with Am-241 source.Finally,neutron beam tests were conducted at the 20th beamline(BL20)of the CSNS,and the response of the monitor to the neutron beam was obtained.Results and conclusion A monitor with detection efficiency of 0.15%@1.8Åand sensitive area of 100×100 mm^(2) was constructed.The monitor maintained good performances for over 6 months and can obtain neutron beam parameters including neutron counting rate and neutron time-of-flight spectrum,etc.Then the neutron beam intensity,neutron wavelength spectrum,etc.can be provided.
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.
