This paper reports the simulation of an electron gun. The effects on the beam quality of some parameters on the beam quality were studied and optimal choices were identified. It gives numerical beam qualities for a co...This paper reports the simulation of an electron gun. The effects on the beam quality of some parameters on the beam quality were studied and optimal choices were identified. It gives numerical beam qualities for a common electrostatic triode gun, and the dependencies on design parameters such as electrode geometries and bias voltages to these electrodes are shown. An electron beam of diameter 5 mm with energy of 5 keV was assumed for the simulation process. Some design parameters were identified as variable parameters in the presence of space charge. These parameters are the inclination angle of emission electrode, the applied voltage to the focusing electrode, the gap width between the emission electrode and the focusing electrode and the diameter of the focusing electrode. The triode extraction system is designed and optimized by using CST software （for Particle Beam Simulations）. The physical design of the extraction system is given in this paper. From the simulation results, it is concluded that the inclination angle of the emission electrode is optimized at 22.5°, the applied voltage to the focusing electrode was optimized and found to be Vfoc =-600 V, the optimal separation distance （gap between emission electrode and focusing electrode） is 4 mm, and the optimal diameter of the emission electrode is 14 mm. Initial results for these efforts aimed at emittance improvement are also given.展开更多
Introduction The ion source is one of the key devices for the high-intensity cyclotron,which exerts influence on the beam intensity and applications of the machine.This paper will provide an introduction to current me...Introduction The ion source is one of the key devices for the high-intensity cyclotron,which exerts influence on the beam intensity and applications of the machine.This paper will provide an introduction to current measures and present relevant experimental study as well as the beam test results.Purpose The existing ion source of the accelerator has a 2-mA output current.Our aim is to increase the current to roughly 5 mA to decrease the reaction time of cyclotron.Therefore,a new ion source was developed.To this end,some simulations were performed,and the simulated ion source was constructed,and then some measurements were noted.Methods and materials The CST code is used to simulate the chamber and extraction system.For construction,some materials such as copper and stainless steel are used.Tungsten wire of 2.1 mm diameter was developed to reach high beam current.Turbo and rotary pump is chosen for system evacuation.Faraday cup can be used for readout.The magnets for plasma confinement are made of Nd–Fe–B material.Results The source assembly consists of a tubular plasma chamber(inner diameter:100 mm;length:150 mm)with 12 columns of permanent magnets(Nd–Fe–B material)to provide a stronger multicusp field,a three-electrode extraction system,and a top cover with a confinement magnet inside.Now,5 mA H−beam can be extracted from the ion source with a plasma electrode aperture of 13 mm under an arc power of 6 kW.The optimum H2 gas flow rate and the change of pressure found during the tuning process of the ion source are presented.展开更多
文摘This paper reports the simulation of an electron gun. The effects on the beam quality of some parameters on the beam quality were studied and optimal choices were identified. It gives numerical beam qualities for a common electrostatic triode gun, and the dependencies on design parameters such as electrode geometries and bias voltages to these electrodes are shown. An electron beam of diameter 5 mm with energy of 5 keV was assumed for the simulation process. Some design parameters were identified as variable parameters in the presence of space charge. These parameters are the inclination angle of emission electrode, the applied voltage to the focusing electrode, the gap width between the emission electrode and the focusing electrode and the diameter of the focusing electrode. The triode extraction system is designed and optimized by using CST software （for Particle Beam Simulations）. The physical design of the extraction system is given in this paper. From the simulation results, it is concluded that the inclination angle of the emission electrode is optimized at 22.5°, the applied voltage to the focusing electrode was optimized and found to be Vfoc =-600 V, the optimal separation distance （gap between emission electrode and focusing electrode） is 4 mm, and the optimal diameter of the emission electrode is 14 mm. Initial results for these efforts aimed at emittance improvement are also given.
文摘Introduction The ion source is one of the key devices for the high-intensity cyclotron,which exerts influence on the beam intensity and applications of the machine.This paper will provide an introduction to current measures and present relevant experimental study as well as the beam test results.Purpose The existing ion source of the accelerator has a 2-mA output current.Our aim is to increase the current to roughly 5 mA to decrease the reaction time of cyclotron.Therefore,a new ion source was developed.To this end,some simulations were performed,and the simulated ion source was constructed,and then some measurements were noted.Methods and materials The CST code is used to simulate the chamber and extraction system.For construction,some materials such as copper and stainless steel are used.Tungsten wire of 2.1 mm diameter was developed to reach high beam current.Turbo and rotary pump is chosen for system evacuation.Faraday cup can be used for readout.The magnets for plasma confinement are made of Nd–Fe–B material.Results The source assembly consists of a tubular plasma chamber(inner diameter:100 mm;length:150 mm)with 12 columns of permanent magnets(Nd–Fe–B material)to provide a stronger multicusp field,a three-electrode extraction system,and a top cover with a confinement magnet inside.Now,5 mA H−beam can be extracted from the ion source with a plasma electrode aperture of 13 mm under an arc power of 6 kW.The optimum H2 gas flow rate and the change of pressure found during the tuning process of the ion source are presented.
