The small-angle neutron scattering(SANS)instrument,one of the first three instruments of the China Spallation Neutron Source(CSNS),is designed to probe the microscopic and mesoscopic structures of materials in the sca...The small-angle neutron scattering(SANS)instrument,one of the first three instruments of the China Spallation Neutron Source(CSNS),is designed to probe the microscopic and mesoscopic structures of materials in the scale range 1–100 nm.A large-area ^(3)He tube array detector has been constructed and operates at the CSNS SANS instrument since August 2018.It consists of 120 linear position-sensitive detector tubes,each 1 m in length and 8 mm in diameter,and filled with ^(3)He gas at 20 bar to obtain a high detection efficiency.The ^(3)He tubes were divided into ten modules,providing an overall area of 1000 mm×1020 mm with a high count rate capability.Because each tube is installed independently,the detector can be quickly repaired in situ by replacing damaged tubes.To reduce air scattering,the SANS detector must operate in a vacuum environment(0.1 mbar).An all-metal sealing technique was adopted to avoid high-voltage breakdown by ensuring a high-voltage connection and an electronic system working in an atmospheric environment.A position resolution of 7.8±0.1 mm(full width at maximum)is measured along the length of the tubes,with a high detection efficiency of 81±2% at 2A.Operating over the past four years,the detector appears to perform well and with a high stability,which supports the SANS instrument to finish approximately 200 user scientific programs.展开更多
The water Cherenkov detector array(WCDA) is an important part of the large high-altitude air shower observatory(LHAASO),which is in a research and development phase.The central scientific goal of LHAASO is to explore ...The water Cherenkov detector array(WCDA) is an important part of the large high-altitude air shower observatory(LHAASO),which is in a research and development phase.The central scientific goal of LHAASO is to explore the origin of high-energy cosmic rays of the universe and to push forward the frontier of new physics.To simplify the WCDA's readout electronics,a prototype of a front-end readout for an application-specific integrated circuit(ASIC) is designed based on the timeover-threshold method to achieve charge-to-time conversion.High-precision time measurement and charge measurement are necessary over a full dynamic range[1-4000photoelectrons(P.E.)].To evaluate the performance of this ASIC,a test system is designed that includes the front-end ASIC test module,digitization module,and test software.The first module needs to be customized for different ASIC versions,whereas the digitization module and test software are tested for general-purpose use.In the digitization module,a field programmable gate array-based time-todigital converter is designed with a bin size of 333 ps,which also integrates an inter-integrated circuit to configure the ASIC test module,and a universal serial bus interface is designed to transfer data to the remote computer.Test results indicate that the time resolution is better than 0.5 ns,and the charge resolution is better than 30%root mean square(RMS) at 1 P.E.and 3%RMS at 4000 P.E.,which are beyond the application requirements.展开更多
Performance characterization for massive photomultiplier tubes(PMTs) is a frequently encountered procedure in large nuclear and particle experiments.To facilitate this work,a dedicated test bench system has been devel...Performance characterization for massive photomultiplier tubes(PMTs) is a frequently encountered procedure in large nuclear and particle experiments.To facilitate this work,a dedicated test bench system has been developed at the Institute of Modern Physics,Chinese Academy of Sciences.The two-dimensional photocathode position scanning capability is an intrinsic function of the test bench,and up to 25 PMTs,with the diameter smaller than 2",can be tested simultaneously.The parameters of the light source pulses can be adjusted in a wide range,thus making it suitable for various characteristics measurements.The test bench system is highly automated with all the controlling operations integrated into a single software.Additionally,the hardware platform is extensible which allows complex testing schemes,and the modularity in the software design makes the migration from one testing configuration to another light-weight and efficient.All these features make the test bench versatile and reusable in different experiments.It has been first used in the construction of the Plastic Scintillator Detector(PSD) of DArk Matter Particle Explorer(DAMPE),and a total of 570 Hamamatsu R4443 tubes were tested successfully.The performance was verified and the testing results are also reported in this article.展开更多
基金supported by the National Key R&D Program of China(No.2021YFA1600703)the National Natural Science Foundation of China(No.12175254)+2 种基金the Youth Innovation Promotion Association CASthe China Spallation Neutron Source Projectthe Innovative Projects of the IHEP(No.E15459U210).
文摘The small-angle neutron scattering(SANS)instrument,one of the first three instruments of the China Spallation Neutron Source(CSNS),is designed to probe the microscopic and mesoscopic structures of materials in the scale range 1–100 nm.A large-area ^(3)He tube array detector has been constructed and operates at the CSNS SANS instrument since August 2018.It consists of 120 linear position-sensitive detector tubes,each 1 m in length and 8 mm in diameter,and filled with ^(3)He gas at 20 bar to obtain a high detection efficiency.The ^(3)He tubes were divided into ten modules,providing an overall area of 1000 mm×1020 mm with a high count rate capability.Because each tube is installed independently,the detector can be quickly repaired in situ by replacing damaged tubes.To reduce air scattering,the SANS detector must operate in a vacuum environment(0.1 mbar).An all-metal sealing technique was adopted to avoid high-voltage breakdown by ensuring a high-voltage connection and an electronic system working in an atmospheric environment.A position resolution of 7.8±0.1 mm(full width at maximum)is measured along the length of the tubes,with a high detection efficiency of 81±2% at 2A.Operating over the past four years,the detector appears to perform well and with a high stability,which supports the SANS instrument to finish approximately 200 user scientific programs.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(KJCX2-YW-N27)the CAS Center for Excellence in Particle Physics(CCEPP)
文摘The water Cherenkov detector array(WCDA) is an important part of the large high-altitude air shower observatory(LHAASO),which is in a research and development phase.The central scientific goal of LHAASO is to explore the origin of high-energy cosmic rays of the universe and to push forward the frontier of new physics.To simplify the WCDA's readout electronics,a prototype of a front-end readout for an application-specific integrated circuit(ASIC) is designed based on the timeover-threshold method to achieve charge-to-time conversion.High-precision time measurement and charge measurement are necessary over a full dynamic range[1-4000photoelectrons(P.E.)].To evaluate the performance of this ASIC,a test system is designed that includes the front-end ASIC test module,digitization module,and test software.The first module needs to be customized for different ASIC versions,whereas the digitization module and test software are tested for general-purpose use.In the digitization module,a field programmable gate array-based time-todigital converter is designed with a bin size of 333 ps,which also integrates an inter-integrated circuit to configure the ASIC test module,and a universal serial bus interface is designed to transfer data to the remote computer.Test results indicate that the time resolution is better than 0.5 ns,and the charge resolution is better than 30%root mean square(RMS) at 1 P.E.and 3%RMS at 4000 P.E.,which are beyond the application requirements.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Science(No.XDA04040202-3)
文摘Performance characterization for massive photomultiplier tubes(PMTs) is a frequently encountered procedure in large nuclear and particle experiments.To facilitate this work,a dedicated test bench system has been developed at the Institute of Modern Physics,Chinese Academy of Sciences.The two-dimensional photocathode position scanning capability is an intrinsic function of the test bench,and up to 25 PMTs,with the diameter smaller than 2",can be tested simultaneously.The parameters of the light source pulses can be adjusted in a wide range,thus making it suitable for various characteristics measurements.The test bench system is highly automated with all the controlling operations integrated into a single software.Additionally,the hardware platform is extensible which allows complex testing schemes,and the modularity in the software design makes the migration from one testing configuration to another light-weight and efficient.All these features make the test bench versatile and reusable in different experiments.It has been first used in the construction of the Plastic Scintillator Detector(PSD) of DArk Matter Particle Explorer(DAMPE),and a total of 570 Hamamatsu R4443 tubes were tested successfully.The performance was verified and the testing results are also reported in this article.
