As one of the most important key technologies for future advanced light source based on the energy recovery linac, a photocathode dc electron gun is supported by Institute of High Energy Physics （IHEP） to address th...As one of the most important key technologies for future advanced light source based on the energy recovery linac, a photocathode dc electron gun is supported by Institute of High Energy Physics （IHEP） to address the technical challenges of producing very low ernittance beams at high average current. Construction of the dc gun is completed and a preliminary high voltage conditioning is carried out up to 440 k V. The design, construction and preliminary HV conditioning results for the dc gun are described.展开更多
In order to develop miniaturized and integrated electron vacuum devices, the electron beam modulation in a field- emission （FE） electron gun based on carbon nanotubes is researched. By feeding a high-frequency field...In order to develop miniaturized and integrated electron vacuum devices, the electron beam modulation in a field- emission （FE） electron gun based on carbon nanotubes is researched. By feeding a high-frequency field between the cathode and the anode, the steady FE electron beam can be modulated in the electron gun. The optimal structure of the electron gun is discovered using 3D electromagnetism simulation software, and the FE electron gun is simulated by PIC simulation software. The results show that a broadband （74-114 GHz） modulation can be achieved by the electron gun with a rhombus channel, and the modulation amplitude of the beam current increases with the increases in the input power and the electrostatic field.展开更多
A gridded thermionic cathode electron gun was developed for the linear accelerator of the High Energy Photon Source(HEPS).An electron gun should provide a large maximum bunch charge with a wide adjustable range.To sat...A gridded thermionic cathode electron gun was developed for the linear accelerator of the High Energy Photon Source(HEPS).An electron gun should provide a large maximum bunch charge with a wide adjustable range.To satisfy these requirements,the shape of the electrode was optimized using a multi-objective genetic algorithm.A large bunch charge with an adjustable range was achieved using the grid-limited gun,the flow of which was analyzed using 3-D simulations.The electron gun has been manufactured and tested,and the measured data of the grid-limited current and simulation results are compared and discussed in this study.展开更多
In this paper, Takagi-Sugeno(T-S) fuzzy control is proposed for stabilizing the output beam of accelerators. To model the nonlinear system, we proposed a hybrid optimization algorithm based on quantum-inspired differe...In this paper, Takagi-Sugeno(T-S) fuzzy control is proposed for stabilizing the output beam of accelerators. To model the nonlinear system, we proposed a hybrid optimization algorithm based on quantum-inspired differential evolution and genetic algorithm. Based on the T-S model identified, the corresponding statefeedback fuzzy controller is designed. The method is applied to the La B6 electron gun system in the industrial radiation accelerator and the simulation results show its effectiveness.展开更多
A new and simple type of electron gun is presented.Unlike conventional electron guns,which require a heated filament or extractor,accelerator and focusing electrodes,this gun uses the collimated electron microchannels...A new and simple type of electron gun is presented.Unlike conventional electron guns,which require a heated filament or extractor,accelerator and focusing electrodes,this gun uses the collimated electron microchannels of an inertial electrostatic confinement（IEC） discharge to achieve the same outcome.A cylindrical cathode is placed coaxially within a cylindrical anode to create the discharge.Collimated beams of electrons and fast neutrals emerge along the axis of the cylindrical cathode.This geometry isolates one of the microchannels that emerge in a negatively biased IEC grid.The internal operating pressure range of the gun is 35-190 m Torr.A small aperture separates the gun from the main vacuum chamber in order to achieve a pressure differential.The chamber was operated at pressures of 4-12 m Torr.The measured current produced by the gun was 0.1-3 m A（0.2-14 m A corrected measurement） for discharge currents of 1-45 m A and discharge voltages of 0.5-12 k V.The collimated electron beam emerges from the aperture into the vacuum chamber.The performance of the gun is unaffected by the pressure differential between the vacuum chamber and the gun.This allows the aperture to be removed and the chamber pressure to be equal to the gun pressure if required.展开更多
Electron beam fluorescence technology is an advanced non-contact measurement in rarefied flow fields,and the fluorescence signal intensity is positively correlated with the electron beam current.The ion bombardment se...Electron beam fluorescence technology is an advanced non-contact measurement in rarefied flow fields,and the fluorescence signal intensity is positively correlated with the electron beam current.The ion bombardment secondary emission electron gun is suitable for the technology.To enhance the beam current,COMSOL simulations and analyses were conducted to examine plasma density distribution in the discharge chamber under the effects of various conditions and the electric field distribution between the cathode and the spacer gap.The anode shape and discharge pressure conditions were optimized to increase plasma density.Additionally,an improved spacer structure was designed with the dual purpose of enhancing the electric field distribution between the cathode-spacer gaps and improving vacuum differential effects.This design modification aims to increase the pass rate of secondary electrons.Both simulation and experimental results demonstrated that the performance of the optimized electron gun was effectively enhanced.When the electrode voltage remains constant and the discharge gas pressure is adjusted to around 8 Pa,the maximum beam current was increased from 0.9 mA to 1.6 mA.展开更多
基金Supported by the Innovation and Technology Fund of Institute of High Energy Physics
文摘As one of the most important key technologies for future advanced light source based on the energy recovery linac, a photocathode dc electron gun is supported by Institute of High Energy Physics （IHEP） to address the technical challenges of producing very low ernittance beams at high average current. Construction of the dc gun is completed and a preliminary high voltage conditioning is carried out up to 440 k V. The design, construction and preliminary HV conditioning results for the dc gun are described.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB933603)the National Natural Science Foundation of China(Grant Nos.U1134006 and 61101041)
文摘In order to develop miniaturized and integrated electron vacuum devices, the electron beam modulation in a field- emission （FE） electron gun based on carbon nanotubes is researched. By feeding a high-frequency field between the cathode and the anode, the steady FE electron beam can be modulated in the electron gun. The optimal structure of the electron gun is discovered using 3D electromagnetism simulation software, and the FE electron gun is simulated by PIC simulation software. The results show that a broadband （74-114 GHz） modulation can be achieved by the electron gun with a rhombus channel, and the modulation amplitude of the beam current increases with the increases in the input power and the electrostatic field.
文摘A gridded thermionic cathode electron gun was developed for the linear accelerator of the High Energy Photon Source(HEPS).An electron gun should provide a large maximum bunch charge with a wide adjustable range.To satisfy these requirements,the shape of the electrode was optimized using a multi-objective genetic algorithm.A large bunch charge with an adjustable range was achieved using the grid-limited gun,the flow of which was analyzed using 3-D simulations.The electron gun has been manufactured and tested,and the measured data of the grid-limited current and simulation results are compared and discussed in this study.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences(No.Y35501A011)
文摘In this paper, Takagi-Sugeno(T-S) fuzzy control is proposed for stabilizing the output beam of accelerators. To model the nonlinear system, we proposed a hybrid optimization algorithm based on quantum-inspired differential evolution and genetic algorithm. Based on the T-S model identified, the corresponding statefeedback fuzzy controller is designed. The method is applied to the La B6 electron gun system in the industrial radiation accelerator and the simulation results show its effectiveness.
文摘A new and simple type of electron gun is presented.Unlike conventional electron guns,which require a heated filament or extractor,accelerator and focusing electrodes,this gun uses the collimated electron microchannels of an inertial electrostatic confinement（IEC） discharge to achieve the same outcome.A cylindrical cathode is placed coaxially within a cylindrical anode to create the discharge.Collimated beams of electrons and fast neutrals emerge along the axis of the cylindrical cathode.This geometry isolates one of the microchannels that emerge in a negatively biased IEC grid.The internal operating pressure range of the gun is 35-190 m Torr.A small aperture separates the gun from the main vacuum chamber in order to achieve a pressure differential.The chamber was operated at pressures of 4-12 m Torr.The measured current produced by the gun was 0.1-3 m A（0.2-14 m A corrected measurement） for discharge currents of 1-45 m A and discharge voltages of 0.5-12 k V.The collimated electron beam emerges from the aperture into the vacuum chamber.The performance of the gun is unaffected by the pressure differential between the vacuum chamber and the gun.This allows the aperture to be removed and the chamber pressure to be equal to the gun pressure if required.
文摘Electron beam fluorescence technology is an advanced non-contact measurement in rarefied flow fields,and the fluorescence signal intensity is positively correlated with the electron beam current.The ion bombardment secondary emission electron gun is suitable for the technology.To enhance the beam current,COMSOL simulations and analyses were conducted to examine plasma density distribution in the discharge chamber under the effects of various conditions and the electric field distribution between the cathode and the spacer gap.The anode shape and discharge pressure conditions were optimized to increase plasma density.Additionally,an improved spacer structure was designed with the dual purpose of enhancing the electric field distribution between the cathode-spacer gaps and improving vacuum differential effects.This design modification aims to increase the pass rate of secondary electrons.Both simulation and experimental results demonstrated that the performance of the optimized electron gun was effectively enhanced.When the electrode voltage remains constant and the discharge gas pressure is adjusted to around 8 Pa,the maximum beam current was increased from 0.9 mA to 1.6 mA.
