We report the world-leading performance of a 1.3 GHz cryomodule equipped with eight 9-cell superconducting radio-frequency cavities that underwent a medium-temperature furnace baking process.During continuous wave hor...We report the world-leading performance of a 1.3 GHz cryomodule equipped with eight 9-cell superconducting radio-frequency cavities that underwent a medium-temperature furnace baking process.During continuous wave horizontal testing,these cavities achieved unprecedented average intrinsic quality factors of 4.0×10^(10)at 20 MV/m and 3.2×10^(10)at 29 MV/m,with no instances of field emission.The cryomodule demonstrates near-complete preservation of ultra-high quality factors and ultra-high accelerating gradients from vertical to horizontal testing,marking a significant milestone in continuous-wave superconducting radio-frequency accelerator technology.This letter presents the cryomodule development experience,includ-ing cavity preparation,cryomodule assembly,degaussing,fast cooldown,and performance testing.展开更多
The time-of-flight high-resolution neutron diffractometer(TREND)at the China Spallation Neutron Source(CSNS)has been successfully equipped with a large-area^(3)He tube array neutron detector,designed to achieve except...The time-of-flight high-resolution neutron diffractometer(TREND)at the China Spallation Neutron Source(CSNS)has been successfully equipped with a large-area^(3)He tube array neutron detector,designed to achieve exceptional resolution and uniformity.The detector system,comprising 14 banks and 134 modules with 1376^(3)He tubes,is optimized for highangle and medium-to-low-angle measurements.Advanced dual-end readout electronics ensure precise charge and timeof-flight measurements,while rigorous performance testing confirmed the system’s spatial resolution and uniformity.Insitu testing using polyethylene samples validated the detector’s operational stability,with counting rate deviations within 3.7%.The system also demonstrated excellent two-dimensional imaging capabilities and adaptability to various neutron wavelength ranges through harmonic division techniques.These results highlight the TREND detector system as a robust and versatile tool for high-resolution neutron diffraction studies.展开更多
Beam lifetime is dominated by Touschek scattering at the Shanghai Synchrotron Radiation Facility(SSRF).Touschek loss rate is affected by probability for scattering beyond the RF acceptance and the volume charge densit...Beam lifetime is dominated by Touschek scattering at the Shanghai Synchrotron Radiation Facility(SSRF).Touschek loss rate is affected by probability for scattering beyond the RF acceptance and the volume charge density of the bench.In the phaseⅡupgrade of the SSRF,a third harmonic superconducting cavity will be used to enhance the Touschek lifetime by lengthening the bunches.The Touschek lifetime improvement factor is affected by the voltage of a harmonic cavity.To stabilize the cavity voltage,a tuning control system was designed to control it.The design of the tuning control system was based on the SSRF third-generation low-level RF control system.Some hardware and specialized algorithms were redesigned to fit the harmonic cavity control.The design of the tuning control system is complete,and the control system has been tested.The test result shows that the fluctuation of amplitude is<±0.34%within 1.5 h,which satisfies the stability requirement.展开更多
The Shanghai High Repetition Rate XFEL and Extreme Light Facility(SHINE)project will use 6001.3 GHz fundamental power couplers,which are modified based on TTF-Ⅲ power couplers,for continuous-wave operation with input...The Shanghai High Repetition Rate XFEL and Extreme Light Facility(SHINE)project will use 6001.3 GHz fundamental power couplers,which are modified based on TTF-Ⅲ power couplers,for continuous-wave operation with input power up to approximately 7 kW.The first batch of 20 sets of 1.3 GHz coupler prototypes was fabricated from three domestic manufacturers for the SHINE project.To better characterize the radio frequency conditioning phenomena for validating the performance of power couplers,a room temperature test stand was designed,constructed,and commissioned for the SHINE 1.3 GHz power couplers.In addition,a horizontal test cryostat was built to test the 1.3 GHz superconducting cavities,fundamental power couplers,tuners,and other components as a set.The results of these tests indicate that the 1.3 GHz couplers are capable of handling up to 14 kW continuous waves.Herein,the main aspects of the radio frequency design and construction of the test stand,along with the test results of the high-power conditioning of the 1.3 GHz couplers,are described.展开更多
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
A digital transfer function measurement system has been embedded in the low-level radio frequency (LLRF) system of the storage ring of the Shanghai Synchrotron Radiation Facility. The measurement results indicate that...A digital transfer function measurement system has been embedded in the low-level radio frequency (LLRF) system of the storage ring of the Shanghai Synchrotron Radiation Facility. The measurement results indicate that the decreased control accuracy at high current is primarily owing to ripples from the high-voltage power supply, the transient beam loading effect, and the digital aliasing effect. The current LLRF algorithm is not able to suppress these disturbances.展开更多
A 1.5 GHz passive third harmonic superconducting cavity was proposed to improve the beam quality and lifetime in the Shanghai Synchrotron Radiation Facility Phase-II beamline project.Lifetime improvement highly depend...A 1.5 GHz passive third harmonic superconducting cavity was proposed to improve the beam quality and lifetime in the Shanghai Synchrotron Radiation Facility Phase-II beamline project.Lifetime improvement highly depends on the resonant frequency of the passive third harmonic superconducting cavity.It is important that the operating frequency of the cavity is within the design range and the cavity has reasonable mechanical stability.A simulation method for the multiphysics coupled analysis has been developed based on the ANSYS code.Multiphysics coupled simulations have been performed under different conditions,such as etching,evacuation,cooling,and preloading.Analyses of mechanical modes and structural stress have been executed.A possible stiffening ring method for the two-cell superconducting niobium cavity has been investigated.In this paper,we present a multiphysics coupled analysis of the third harmonic cavity using a finite element analysis code.The results of the analysis show that a reliable frequency for the cavity after electron beam welding is 1498.033 MHz,and the corresponding frequency of the pre-tuning goal is 1496.163 MHz.A naked cavity is a reasonable option based on structural stress and mechanical modal analyses.A frequency range of±500 kHz and limiting tolerable displacement of±0.35 mm are proposed for the design of the frequency tuner.展开更多
The inherent electrocatalytic potential of transition metal phosphides(TMPs)for oxygen evolution is influenced by the reduced efficiency of electron transfer resulting from the interaction between electronegative phos...The inherent electrocatalytic potential of transition metal phosphides(TMPs)for oxygen evolution is influenced by the reduced efficiency of electron transfer resulting from the interaction between electronegative phosphorus atoms and transition metals.Here,we introduce Fe into Ni_(2)P nanocrystals by thermal injection synthesis method,and anchor them on nickel foam(NF)by facile spraying to prepare self-supporting oxygen evolution reaction(OER)electrocatalyst.Promisingly,the optimized electrode of Ni_(2)P-Fe-2/NF demonstrates low overpotentials of 212 mV with 10 mA·cm^(-2)and a 0.9%decay within300 h test of 50 mA·cm^(-2).Notably,when electrode size was expanded to 600 cm^(2)and applied to a larger electrolyzer,its 9 h decay rate at 6 A current was only 1.69%.Characterization results show that Fe doped NiOOH is generated during OER reaction as actual catalyst,Results from density functional theory(DFT)computations suggest that Fe doping shifts NiOOH d-band center to Fermi level,lowering critical *OOH intermediates formation energy barrier during the OER reaction.These findings inform the large-scale industrial application of TMPs as robust electrocatalysts.展开更多
Background Large areas of 3He neutron detector array and corresponding readout electronics are used in the MPI built at China Spallation Neutron Source(CSNS)to measure the position and flight time of scattered neutron...Background Large areas of 3He neutron detector array and corresponding readout electronics are used in the MPI built at China Spallation Neutron Source(CSNS)to measure the position and flight time of scattered neutrons,and MPI has a high requirement for the position resolution of 3He neutron detector.A 3He neutron detector readout electronics prototype composed of two front-end boards and one digital readout board is designed to meet the above requirements.Purpose Testing the whole readout electronics system before its mass production to ensure it can run correctly and fulfill the functional and performance requirements.Methods The test of the readout electronics prototype is implemented in the laboratory,and a signal generator is used to generate electronic signals instead of actual neutron signals.The position resolution test of the readout electronics prototype with 3He tubes is carried out in the No.20 beamline measurement room of CSNS.Results and Conclusion The functional and performance tests in the laboratory state that the readout electronics prototype can fulfill the readout requirements.The typical value of charge resolution is 0.85 fC;the integral nonlinearity of charge is 0.094%in the input charge range from 100 to 800 fC.The position resolution test result of the prototype with 3He tubes is better than the design requirement of 10 mm and also quite good compared with that of some other commercial products.These tests provide a reliable basis for the mass production of the readout electronics prototype.展开更多
基金supported by Zhangjiang Laboratory,the SHINE R&D project(No.2017SHZDZX02)the SHINE projectthe National Natural Science Foundation of China(No.12125508).
文摘We report the world-leading performance of a 1.3 GHz cryomodule equipped with eight 9-cell superconducting radio-frequency cavities that underwent a medium-temperature furnace baking process.During continuous wave horizontal testing,these cavities achieved unprecedented average intrinsic quality factors of 4.0×10^(10)at 20 MV/m and 3.2×10^(10)at 29 MV/m,with no instances of field emission.The cryomodule demonstrates near-complete preservation of ultra-high quality factors and ultra-high accelerating gradients from vertical to horizontal testing,marking a significant milestone in continuous-wave superconducting radio-frequency accelerator technology.This letter presents the cryomodule development experience,includ-ing cavity preparation,cryomodule assembly,degaussing,fast cooldown,and performance testing.
基金supported by the National Natural Science Foundation of China through the Young Fund Project titled“Research on Polarized Neutron Detector System”(Project Approval No.12205326)support was provided by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2023B0303000003)the Guangdong Provincial Key Laboratory of Advanced Particle Detection Technology(Grant No.2024B1212010005).
文摘The time-of-flight high-resolution neutron diffractometer(TREND)at the China Spallation Neutron Source(CSNS)has been successfully equipped with a large-area^(3)He tube array neutron detector,designed to achieve exceptional resolution and uniformity.The detector system,comprising 14 banks and 134 modules with 1376^(3)He tubes,is optimized for highangle and medium-to-low-angle measurements.Advanced dual-end readout electronics ensure precise charge and timeof-flight measurements,while rigorous performance testing confirmed the system’s spatial resolution and uniformity.Insitu testing using polyethylene samples validated the detector’s operational stability,with counting rate deviations within 3.7%.The system also demonstrated excellent two-dimensional imaging capabilities and adaptability to various neutron wavelength ranges through harmonic division techniques.These results highlight the TREND detector system as a robust and versatile tool for high-resolution neutron diffraction studies.
文摘Beam lifetime is dominated by Touschek scattering at the Shanghai Synchrotron Radiation Facility(SSRF).Touschek loss rate is affected by probability for scattering beyond the RF acceptance and the volume charge density of the bench.In the phaseⅡupgrade of the SSRF,a third harmonic superconducting cavity will be used to enhance the Touschek lifetime by lengthening the bunches.The Touschek lifetime improvement factor is affected by the voltage of a harmonic cavity.To stabilize the cavity voltage,a tuning control system was designed to control it.The design of the tuning control system was based on the SSRF third-generation low-level RF control system.Some hardware and specialized algorithms were redesigned to fit the harmonic cavity control.The design of the tuning control system is complete,and the control system has been tested.The test result shows that the fluctuation of amplitude is<±0.34%within 1.5 h,which satisfies the stability requirement.
基金supported by Shanghai Municipal Science and Technology Major Project(No.2017SHZDZX02)。
文摘The Shanghai High Repetition Rate XFEL and Extreme Light Facility(SHINE)project will use 6001.3 GHz fundamental power couplers,which are modified based on TTF-Ⅲ power couplers,for continuous-wave operation with input power up to approximately 7 kW.The first batch of 20 sets of 1.3 GHz coupler prototypes was fabricated from three domestic manufacturers for the SHINE project.To better characterize the radio frequency conditioning phenomena for validating the performance of power couplers,a room temperature test stand was designed,constructed,and commissioned for the SHINE 1.3 GHz power couplers.In addition,a horizontal test cryostat was built to test the 1.3 GHz superconducting cavities,fundamental power couplers,tuners,and other components as a set.The results of these tests indicate that the 1.3 GHz couplers are capable of handling up to 14 kW continuous waves.Herein,the main aspects of the radio frequency design and construction of the test stand,along with the test results of the high-power conditioning of the 1.3 GHz couplers,are described.
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.
文摘A digital transfer function measurement system has been embedded in the low-level radio frequency (LLRF) system of the storage ring of the Shanghai Synchrotron Radiation Facility. The measurement results indicate that the decreased control accuracy at high current is primarily owing to ripples from the high-voltage power supply, the transient beam loading effect, and the digital aliasing effect. The current LLRF algorithm is not able to suppress these disturbances.
基金supported by the National Natural Science Foundation of China(No.11335014)
文摘A 1.5 GHz passive third harmonic superconducting cavity was proposed to improve the beam quality and lifetime in the Shanghai Synchrotron Radiation Facility Phase-II beamline project.Lifetime improvement highly depends on the resonant frequency of the passive third harmonic superconducting cavity.It is important that the operating frequency of the cavity is within the design range and the cavity has reasonable mechanical stability.A simulation method for the multiphysics coupled analysis has been developed based on the ANSYS code.Multiphysics coupled simulations have been performed under different conditions,such as etching,evacuation,cooling,and preloading.Analyses of mechanical modes and structural stress have been executed.A possible stiffening ring method for the two-cell superconducting niobium cavity has been investigated.In this paper,we present a multiphysics coupled analysis of the third harmonic cavity using a finite element analysis code.The results of the analysis show that a reliable frequency for the cavity after electron beam welding is 1498.033 MHz,and the corresponding frequency of the pre-tuning goal is 1496.163 MHz.A naked cavity is a reasonable option based on structural stress and mechanical modal analyses.A frequency range of±500 kHz and limiting tolerable displacement of±0.35 mm are proposed for the design of the frequency tuner.
基金financially supported by Shenzhen Bureau of Science,Technology and Innovation Commission(No.JSGG20200914113601003)the National Natural Science Foundation of China(No.51971080)。
文摘The inherent electrocatalytic potential of transition metal phosphides(TMPs)for oxygen evolution is influenced by the reduced efficiency of electron transfer resulting from the interaction between electronegative phosphorus atoms and transition metals.Here,we introduce Fe into Ni_(2)P nanocrystals by thermal injection synthesis method,and anchor them on nickel foam(NF)by facile spraying to prepare self-supporting oxygen evolution reaction(OER)electrocatalyst.Promisingly,the optimized electrode of Ni_(2)P-Fe-2/NF demonstrates low overpotentials of 212 mV with 10 mA·cm^(-2)and a 0.9%decay within300 h test of 50 mA·cm^(-2).Notably,when electrode size was expanded to 600 cm^(2)and applied to a larger electrolyzer,its 9 h decay rate at 6 A current was only 1.69%.Characterization results show that Fe doped NiOOH is generated during OER reaction as actual catalyst,Results from density functional theory(DFT)computations suggest that Fe doping shifts NiOOH d-band center to Fermi level,lowering critical *OOH intermediates formation energy barrier during the OER reaction.These findings inform the large-scale industrial application of TMPs as robust electrocatalysts.
基金the State Key Laboratory of Particle Detection and Electronics and supported by a grant from the Scientific Research Foundation of Advanced talents(innovation team)of DGUT(No.KCYCXPT2016004).
文摘Background Large areas of 3He neutron detector array and corresponding readout electronics are used in the MPI built at China Spallation Neutron Source(CSNS)to measure the position and flight time of scattered neutrons,and MPI has a high requirement for the position resolution of 3He neutron detector.A 3He neutron detector readout electronics prototype composed of two front-end boards and one digital readout board is designed to meet the above requirements.Purpose Testing the whole readout electronics system before its mass production to ensure it can run correctly and fulfill the functional and performance requirements.Methods The test of the readout electronics prototype is implemented in the laboratory,and a signal generator is used to generate electronic signals instead of actual neutron signals.The position resolution test of the readout electronics prototype with 3He tubes is carried out in the No.20 beamline measurement room of CSNS.Results and Conclusion The functional and performance tests in the laboratory state that the readout electronics prototype can fulfill the readout requirements.The typical value of charge resolution is 0.85 fC;the integral nonlinearity of charge is 0.094%in the input charge range from 100 to 800 fC.The position resolution test result of the prototype with 3He tubes is better than the design requirement of 10 mm and also quite good compared with that of some other commercial products.These tests provide a reliable basis for the mass production of the readout electronics prototype.
