An outline of the complete design of the cryogenic system, including the detection of quench signals, the processing flow after a quench and the concrete measures of pressure release for EAST is described in this pape...An outline of the complete design of the cryogenic system, including the detection of quench signals, the processing flow after a quench and the concrete measures of pressure release for EAST is described in this paper. The hardware and software configurations on DeltaV DCS are illustrated in detail. The results of quench protection testing in cooling experiments are also analyzed.展开更多
Pneumatic cryogenic control valves(PCCV)are designed to meet the special requirements for the large cryogenic helium refrigeration system.Polychlorotrifluoroethylene(PCTFE)is adopted as the flat seal material of the v...Pneumatic cryogenic control valves(PCCV)are designed to meet the special requirements for the large cryogenic helium refrigeration system.Polychlorotrifluoroethylene(PCTFE)is adopted as the flat seal material of the valve seat.The leakage rates and compressive strain of the PCTFE gasket with different sealing stress are tested at both room temperature(293 K)and liquid nitrogen temperature(77 K).After 300 open/close cycles,the experimental results show that the sealing properties of the PCTFE gasket are improved.The leakage rates are about 10-8(293 K)and 10-4(77 K)Pam3 s-1 respectively.Finally,the effects of working pressure on sealing characteristics are discussed.The working pressure has little effect on compressive strain but it has a great influence on leakage rate.The leakage rate is linear with the working pressure of inlet at room temperature,but at liquid nitrogen temperature the leakage rate is linear with the square of the working pressure.展开更多
The cryogenic ground support equipment (CGSE) is an important part of Alpha Magnetic Spectrometer-02 (AMS-02) experiment which is a particle physics experiment. CGSE is used to cool down the superconducting magnet of ...The cryogenic ground support equipment (CGSE) is an important part of Alpha Magnetic Spectrometer-02 (AMS-02) experiment which is a particle physics experiment. CGSE is used to cool down the superconducting magnet of AMS-02 to its operating temperature of 1.8K and to fill the magnet helium tank with superfluid helium. This paper introduces the control system of CGSE and presents the performance of the system.展开更多
A superconducting cryogenic system has been designed and deployed in the Beijing Electron- Positron Collider Upgrade Project （BEPC II ）. The system consists of a Siemens PLC （ST-PLC, Programmable Logic Controller）...A superconducting cryogenic system has been designed and deployed in the Beijing Electron- Positron Collider Upgrade Project （BEPC II ）. The system consists of a Siemens PLC （ST-PLC, Programmable Logic Controller） for the compressor control, an Allen Bradley （AB） PLC for the cryogenic equipments, and the Experimental Physics and Industrial Control System （EPICS） that integrates the PLCs. The system fully automates the superconducting cryogenic control with process control, PID （Proportional-lntegral-Differential） control loops, real-time data access and data storage, alarm handler and human machine interface. It is capable of automatic recovery as well. This paper describes the BEPC 11 cryogenic control system, data communication between ST-PLC and EPICS Input/Output Controllers （IOCs）, and the integration of the flow control, the low level interlock, the AB-PLC, and EPICS.展开更多
Background The cryogenic control system of BEPCII has been in stable operation for more than 10 years,providing techni-cal support for the generation of cryogenic environments.The core hardware of the cryogenic contro...Background The cryogenic control system of BEPCII has been in stable operation for more than 10 years,providing techni-cal support for the generation of cryogenic environments.The core hardware of the cryogenic control system is composed of PLC and VME controller,and the operating software includes PLC commercial software and EPICS.However,some hardware and software are obsolete.Purpose An upgrade prototype of the cryogenic control system is designed and built to study the compatibility contradiction between software and hardware,and ensure the long-term stable operation of cryogenic system.Method Keep the hardware architecture,upgrade the software and hardware modules of PLC and VME respectively,and test the system compatibility.Conclusion The upgrading prototype of the cryogenic control system solves the problem of software and hardware compat-ibility,and makes it possible to achieve a seamless and smooth upgrade of the cryogenic control system in the future.展开更多
Electron affinities (EAs) of most lanthanide elements still remain unknown due to their relatively low EA values. In the present work, the cryogenically controlled ion trap is used for accumulating atomic lutetium ani...Electron affinities (EAs) of most lanthanide elements still remain unknown due to their relatively low EA values. In the present work, the cryogenically controlled ion trap is used for accumulating atomic lutetium anion Lu^-, which makes the measurement of electron affinity of lutetium become practicable. The high-resolution photoelectron spectra of Lu^- are obtained via the slow-electron velocity-map imaging method. The electron affinity of Lu is determined to be 1926.2(50) cm^-1 or 0.23882(62) eV. In addition, two excited states of Lu^- are observed.展开更多
基金supported by National Meg-Science Engineering Project of Chinese Government (No.10575105)
文摘An outline of the complete design of the cryogenic system, including the detection of quench signals, the processing flow after a quench and the concrete measures of pressure release for EAST is described in this paper. The hardware and software configurations on DeltaV DCS are illustrated in detail. The results of quench protection testing in cooling experiments are also analyzed.
基金supported by the fund of the State Key Laboratory of Technologies in Space Cryogenic Propellants (Grant No. SKLTSCP1210)
文摘Pneumatic cryogenic control valves(PCCV)are designed to meet the special requirements for the large cryogenic helium refrigeration system.Polychlorotrifluoroethylene(PCTFE)is adopted as the flat seal material of the valve seat.The leakage rates and compressive strain of the PCTFE gasket with different sealing stress are tested at both room temperature(293 K)and liquid nitrogen temperature(77 K).After 300 open/close cycles,the experimental results show that the sealing properties of the PCTFE gasket are improved.The leakage rates are about 10-8(293 K)and 10-4(77 K)Pam3 s-1 respectively.Finally,the effects of working pressure on sealing characteristics are discussed.The working pressure has little effect on compressive strain but it has a great influence on leakage rate.The leakage rate is linear with the working pressure of inlet at room temperature,but at liquid nitrogen temperature the leakage rate is linear with the square of the working pressure.
基金the National Basic Research Program(973) of China (No. 2004CB720703)
文摘The cryogenic ground support equipment (CGSE) is an important part of Alpha Magnetic Spectrometer-02 (AMS-02) experiment which is a particle physics experiment. CGSE is used to cool down the superconducting magnet of AMS-02 to its operating temperature of 1.8K and to fill the magnet helium tank with superfluid helium. This paper introduces the control system of CGSE and presents the performance of the system.
文摘A superconducting cryogenic system has been designed and deployed in the Beijing Electron- Positron Collider Upgrade Project （BEPC II ）. The system consists of a Siemens PLC （ST-PLC, Programmable Logic Controller） for the compressor control, an Allen Bradley （AB） PLC for the cryogenic equipments, and the Experimental Physics and Industrial Control System （EPICS） that integrates the PLCs. The system fully automates the superconducting cryogenic control with process control, PID （Proportional-lntegral-Differential） control loops, real-time data access and data storage, alarm handler and human machine interface. It is capable of automatic recovery as well. This paper describes the BEPC 11 cryogenic control system, data communication between ST-PLC and EPICS Input/Output Controllers （IOCs）, and the integration of the flow control, the low level interlock, the AB-PLC, and EPICS.
文摘Background The cryogenic control system of BEPCII has been in stable operation for more than 10 years,providing techni-cal support for the generation of cryogenic environments.The core hardware of the cryogenic control system is composed of PLC and VME controller,and the operating software includes PLC commercial software and EPICS.However,some hardware and software are obsolete.Purpose An upgrade prototype of the cryogenic control system is designed and built to study the compatibility contradiction between software and hardware,and ensure the long-term stable operation of cryogenic system.Method Keep the hardware architecture,upgrade the software and hardware modules of PLC and VME respectively,and test the system compatibility.Conclusion The upgrading prototype of the cryogenic control system solves the problem of software and hardware compat-ibility,and makes it possible to achieve a seamless and smooth upgrade of the cryogenic control system in the future.
基金supported by the National Natural Science Foundation of China (No.91736102)the National Key R&D program of China (No.2018YFA0306504)
文摘Electron affinities (EAs) of most lanthanide elements still remain unknown due to their relatively low EA values. In the present work, the cryogenically controlled ion trap is used for accumulating atomic lutetium anion Lu^-, which makes the measurement of electron affinity of lutetium become practicable. The high-resolution photoelectron spectra of Lu^- are obtained via the slow-electron velocity-map imaging method. The electron affinity of Lu is determined to be 1926.2(50) cm^-1 or 0.23882(62) eV. In addition, two excited states of Lu^- are observed.
