低温永磁波荡器(Cryogenic Permanent Magnet Undulator,CPMU)是目前插入件技术发展的主要方向之一,其利用一些永磁材料,如钕铁硼(Nd Fe B)或镨铁棚(Pr Fe B)的磁场性能在低温下明显高于室温的特性来提高波荡器性能和光源束流品质,工作...低温永磁波荡器(Cryogenic Permanent Magnet Undulator,CPMU)是目前插入件技术发展的主要方向之一,其利用一些永磁材料,如钕铁硼(Nd Fe B)或镨铁棚(Pr Fe B)的磁场性能在低温下明显高于室温的特性来提高波荡器性能和光源束流品质,工作温区为50-150 K,需要冷却系统的冷却。CPMU冷却系统主要包括过冷液氮冷却系统和磁体阵列冷却回路。本文介绍了上海光源(Shanghai Synchrotron Radiation Facility,SSRF)CPMU过冷液氮冷却系统的设计方案和设计参数,进行了系统主要热负载的分析;对冷却系统中关键设备之一的过冷换热器进行了设计,并计算分析了过冷氮流经CPMU冷却系统的全程阻力损失,为系统另一关键设备液氮泵的选型提供依据。对CPMU过冷液氮冷却系统进行的在线测试表明,该设计满足CPMU样机的冷却需求。展开更多
Background High energy photon source(HEPS)is the fourth-generation light source,which uses a large number of highperformance insertion devices to generate synchrotron radiation.The control system is an important part ...Background High energy photon source(HEPS)is the fourth-generation light source,which uses a large number of highperformance insertion devices to generate synchrotron radiation.The control system is an important part of the insertion device(ID).Purpose Cryogenic permanent magnet undulator(CPMU)is one kind of IDs that works in liquid nitrogen temperature and ultra-high vacuum environment,and its control system is more difficult and complex than in-air ID.The design of the control system for CPMU will be introduced in detail.Method The sub-systems include high-precision magnetic gap control,safety protection,measurement and compensation of magnetic gap at cryogenic temperature and cryogenic temperature monitoring.Mature,reliable,stable technical schemes are designed to meet the technical specifications of sub-systems.Results The experiment results show that the magnetic gap motion accuracy can be controlled within 0.2–0.3μm under the step size of 1μm.The safety protection system has been tested in turn,and the predetermined protection can be achieved.The average value of magnetic gap cold contraction is 1.512 mm measured by optical micrometer,and the compensation is realized by software.The average temperature of the main magnet structure measured by the temperature sensors is 81.0 K,and the temperature gradient is 0.7 K/m.The temperature monitoring is reliable and stable.Conclusion The CPMU control system which is based on EPICS has been successfully applied to the CPMU prototype,and the test results have met the design specifications.展开更多
文摘Background High energy photon source(HEPS)is the fourth-generation light source,which uses a large number of highperformance insertion devices to generate synchrotron radiation.The control system is an important part of the insertion device(ID).Purpose Cryogenic permanent magnet undulator(CPMU)is one kind of IDs that works in liquid nitrogen temperature and ultra-high vacuum environment,and its control system is more difficult and complex than in-air ID.The design of the control system for CPMU will be introduced in detail.Method The sub-systems include high-precision magnetic gap control,safety protection,measurement and compensation of magnetic gap at cryogenic temperature and cryogenic temperature monitoring.Mature,reliable,stable technical schemes are designed to meet the technical specifications of sub-systems.Results The experiment results show that the magnetic gap motion accuracy can be controlled within 0.2–0.3μm under the step size of 1μm.The safety protection system has been tested in turn,and the predetermined protection can be achieved.The average value of magnetic gap cold contraction is 1.512 mm measured by optical micrometer,and the compensation is realized by software.The average temperature of the main magnet structure measured by the temperature sensors is 81.0 K,and the temperature gradient is 0.7 K/m.The temperature monitoring is reliable and stable.Conclusion The CPMU control system which is based on EPICS has been successfully applied to the CPMU prototype,and the test results have met the design specifications.
