Purpose The High Energy Photon Source(HEPS)is a synchrotron radiation source with an ultrahigh brightness and under construction in China.Its accelerator system is comprised of a 6-GeV storage ring,a full energy boost...Purpose The High Energy Photon Source(HEPS)is a synchrotron radiation source with an ultrahigh brightness and under construction in China.Its accelerator system is comprised of a 6-GeV storage ring,a full energy booster,a 500-meV Linac and three transport lines.With deepening investigations on the physics designs of the storage ring and the booster,the physics scheme of the Linac has evolved through multiple versions.Methods The final version of the Linac,including the electron gun,bunching system and main accelerator,has been deter-mined.The Linac is an s-band normal conducting electron linear accelerator with a very high bunch charge and a large bunch charge range.Results Based on simulations,the Linac could provide electron bunches with charge greater than 8.5-nC,meeting the energy spread and emittance requirements.Conclusions This paper first reviews the evolution and main considerations for different design versions and then describes the physics design and dynamic simulation results of the final scheme in detail.展开更多
Purpose The High Energy Photon Source is a fourth-generation synchrotron radiation source being built in China.It is comprised of a storage ring,a full energy booster,a 500-MeV Linac and three transport lines.The puls...Purpose The High Energy Photon Source is a fourth-generation synchrotron radiation source being built in China.It is comprised of a storage ring,a full energy booster,a 500-MeV Linac and three transport lines.The pulse charge at the exit of the Linac is required to be up to 7 nC.Both single bunch and three bunches in a beam pulse might be needed according to the studies on instabilities of the booster and the beam dynamic of the main Linac.Methods A bunching system consisting of both sub-harmonic and fundamental frequency structures is designed to meet the requirements.To obtain high transmission efficiency and control the emittance growth,multi-objective genetic algorithm is introduced to optimize the electromagnetic parameters of these structures.Results In this paper,detailed optimization process and the final results are presented.The total transmission efficiency of the bunching system is 97%,and the transmission efficiency of the main bunch is 95%.The normalized RMS emittance of 8.5 nC included beam charge is smaller than 60 mm mrad.Conclusions The design of the bunching system is presented,and both the pulse charge and the beam emittance well meet the design requirement.展开更多
Purpose The high energy photon source(HEPS),a 6-GeV synchrotron radiation facility with ultralow emittance,is under construction in China.Three transfer lines are designed for HEPS.One low-energy transfer line is used...Purpose The high energy photon source(HEPS),a 6-GeV synchrotron radiation facility with ultralow emittance,is under construction in China.Three transfer lines are designed for HEPS.One low-energy transfer line is used to deliver the 500 MeV beam provided by the linac to the booster.Two high-energy transfer lines are used to connect the booster and the storage ring to realize beam accumulation in the booster at 6 GeV.Method The design of the transfer lines is closely related to the layout and optics design of the storage ring,booster and linac.Based on the physics design of the storage ring,booster and linac,the design of the transfer lines has been adjusted.Results and conclusion In this paper,the considerations and design of the latest lattice of transfer lines are described.The design satisfies the requirements of the high efficiency transmission and injection.展开更多
Background High-energy photon source under construction is a fourth-generation synchrotronradiation light source with energy of 6 Gev and ultra-low emittance(lower than 0.1 nm rad).The ultra-low beam emittance require...Background High-energy photon source under construction is a fourth-generation synchrotronradiation light source with energy of 6 Gev and ultra-low emittance(lower than 0.1 nm rad).The ultra-low beam emittance requires high beam stability.Purpose In order to meet this requirement of low beam emittance,the fast close orbit correctionsystem is used to keep beam on the right orbit.The fast close orbit correction system need fast corrector power supply to drive the calibration magnet to complete track correction.So,a fastcorrector power supply prototype with high bandwidth and low current ripple to improve the performance of the fast close orbit correction system to prove the high beam stability had beendeveloped.Methods The prototype use a novel multilevel switch-mode structure to provide the dynamicrequirement.The prototype adopts FPGA for full-digital control and use high-speed ADC with temperature control.By using a precision sampling circuit(ADC+DCCT),the prototypeoutputs current ripple can meet the requirement.Results and conclusion The designed for HEPS meet the design requirement.Through test,the prototype has asmall signal bandwidth of 10 kHz and output current ripple lower than 20 ppm.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
Purpose A novel high-directivity high-power waveguide directional coupler(DC)working at 2998.8 MHz is developed for the High Energy Photon Source.It can help the phase control system to obtain a very accurate microwav...Purpose A novel high-directivity high-power waveguide directional coupler(DC)working at 2998.8 MHz is developed for the High Energy Photon Source.It can help the phase control system to obtain a very accurate microwave signal,which is very important to minimize the beam emittance.Methods The novel reversely placed T-type coupling piece helps to obtain a high directivity.The N-type high-vacuum feedthroughs for vacuum sealing instead of the traditional ceramic plate is beneficial to holding a higher peak power.The simulation and the high-power commissioning are accomplished in the Institute of High Energy Physics(IHEP),while the fabrication and the low-power test are conducted in cooperation with the manufacturer.Results Both the single-coupler and the dual-coupler DCs are developed with a directivity of more than 35 dB while keeping the coupling factor within 60±0.5 dB.Finally,69.4%of all the fifty-two mass produced DCs have got a directivity of more than 40 dB.Conclusion:The mature manufacturing process for mass production is obtained.The novel high-directivity high-power waveguide DC can be mass produced with an actually internationally leading performance.展开更多
基金supported by the High Energy Photon Source(HEPS)project,a major national science and technology infrastruc-ture projectthe National Natural Science Foundation of China under Grants(11705214,11675174)the Youth Innovation Promotion Association CAS(2019016)
文摘Purpose The High Energy Photon Source(HEPS)is a synchrotron radiation source with an ultrahigh brightness and under construction in China.Its accelerator system is comprised of a 6-GeV storage ring,a full energy booster,a 500-meV Linac and three transport lines.With deepening investigations on the physics designs of the storage ring and the booster,the physics scheme of the Linac has evolved through multiple versions.Methods The final version of the Linac,including the electron gun,bunching system and main accelerator,has been deter-mined.The Linac is an s-band normal conducting electron linear accelerator with a very high bunch charge and a large bunch charge range.Results Based on simulations,the Linac could provide electron bunches with charge greater than 8.5-nC,meeting the energy spread and emittance requirements.Conclusions This paper first reviews the evolution and main considerations for different design versions and then describes the physics design and dynamic simulation results of the final scheme in detail.
基金supported by National Natural Science Foundation of China under Grants(11705214,11675174)Youth Innovation Promotion Asso-ciation CAS(2019016)
文摘Purpose The High Energy Photon Source is a fourth-generation synchrotron radiation source being built in China.It is comprised of a storage ring,a full energy booster,a 500-MeV Linac and three transport lines.The pulse charge at the exit of the Linac is required to be up to 7 nC.Both single bunch and three bunches in a beam pulse might be needed according to the studies on instabilities of the booster and the beam dynamic of the main Linac.Methods A bunching system consisting of both sub-harmonic and fundamental frequency structures is designed to meet the requirements.To obtain high transmission efficiency and control the emittance growth,multi-objective genetic algorithm is introduced to optimize the electromagnetic parameters of these structures.Results In this paper,detailed optimization process and the final results are presented.The total transmission efficiency of the bunching system is 97%,and the transmission efficiency of the main bunch is 95%.The normalized RMS emittance of 8.5 nC included beam charge is smaller than 60 mm mrad.Conclusions The design of the bunching system is presented,and both the pulse charge and the beam emittance well meet the design requirement.
基金supported by high-energy photon source(HEPS),a major national science and technology infrastruc-tureNational Natural Science Foundation of China(No.11805217,11922512)Youth Innovation Promotion Association of Chinese Academy of Sciences(No.Y201904)
文摘Purpose The high energy photon source(HEPS),a 6-GeV synchrotron radiation facility with ultralow emittance,is under construction in China.Three transfer lines are designed for HEPS.One low-energy transfer line is used to deliver the 500 MeV beam provided by the linac to the booster.Two high-energy transfer lines are used to connect the booster and the storage ring to realize beam accumulation in the booster at 6 GeV.Method The design of the transfer lines is closely related to the layout and optics design of the storage ring,booster and linac.Based on the physics design of the storage ring,booster and linac,the design of the transfer lines has been adjusted.Results and conclusion In this paper,the considerations and design of the latest lattice of transfer lines are described.The design satisfies the requirements of the high efficiency transmission and injection.
文摘Background High-energy photon source under construction is a fourth-generation synchrotronradiation light source with energy of 6 Gev and ultra-low emittance(lower than 0.1 nm rad).The ultra-low beam emittance requires high beam stability.Purpose In order to meet this requirement of low beam emittance,the fast close orbit correctionsystem is used to keep beam on the right orbit.The fast close orbit correction system need fast corrector power supply to drive the calibration magnet to complete track correction.So,a fastcorrector power supply prototype with high bandwidth and low current ripple to improve the performance of the fast close orbit correction system to prove the high beam stability had beendeveloped.Methods The prototype use a novel multilevel switch-mode structure to provide the dynamicrequirement.The prototype adopts FPGA for full-digital control and use high-speed ADC with temperature control.By using a precision sampling circuit(ADC+DCCT),the prototypeoutputs current ripple can meet the requirement.Results and conclusion The designed for HEPS meet the design requirement.Through test,the prototype has asmall signal bandwidth of 10 kHz and output current ripple lower than 20 ppm.
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.
基金Funded by Youth Innovation Promotion Association CAS(2020015)
文摘Purpose A novel high-directivity high-power waveguide directional coupler(DC)working at 2998.8 MHz is developed for the High Energy Photon Source.It can help the phase control system to obtain a very accurate microwave signal,which is very important to minimize the beam emittance.Methods The novel reversely placed T-type coupling piece helps to obtain a high directivity.The N-type high-vacuum feedthroughs for vacuum sealing instead of the traditional ceramic plate is beneficial to holding a higher peak power.The simulation and the high-power commissioning are accomplished in the Institute of High Energy Physics(IHEP),while the fabrication and the low-power test are conducted in cooperation with the manufacturer.Results Both the single-coupler and the dual-coupler DCs are developed with a directivity of more than 35 dB while keeping the coupling factor within 60±0.5 dB.Finally,69.4%of all the fifty-two mass produced DCs have got a directivity of more than 40 dB.Conclusion:The mature manufacturing process for mass production is obtained.The novel high-directivity high-power waveguide DC can be mass produced with an actually internationally leading performance.
