We recently set up a time-resolved optical beam diagnostic system. Using this system, we measured the high current electron beam energy in the accelerator under construction. This paper introduces the principle of the...We recently set up a time-resolved optical beam diagnostic system. Using this system, we measured the high current electron beam energy in the accelerator under construction. This paper introduces the principle of the diagnostic system, describes the setup, and shows the results. A bending beam line was designed using an existing magnetic analyzer with a 300 mm-bending radius and a 60° bending angle at hard-edge approximation. Calculations show that the magnitude of the beam energy is about 18 MeV, and the energy spread is within 2%. Our results agree well with the initial estimates deduced from the diode voltage approach.展开更多
The control strategy is presented using passive and active hybrid magnetically suspended flywheels(P&A MSFWs),which can help meet the requirements of high precision and high stability for earth-observation satellit...The control strategy is presented using passive and active hybrid magnetically suspended flywheels(P&A MSFWs),which can help meet the requirements of high precision and high stability for earth-observation satellites.Compared with the conventional flywheel,P&A MSFW has more rotation degrees of freedom(DOFs)since the rotor is suspended by magnetic bearings,and thus requires more efficient controllers.A modified sliding mode control law(SMC)to our novel nonlinear and coupled system is presented,which is interrupted by inertia matrix uncertainties and external disturbances.SMC law via Lyapunov method is improved,and a fuzzy control scheme is used to attenuate the chatting and control attitude accuracy and maintain the robustness of SMC.Simulation results are provided to illustrate the efficiency of our model by using our control law.展开更多
Purpose High current beam is required for CSNS update in future.Over 50 mA H-will be designed to deliver to the linac in CSNSⅡ.For the present state of CSNS ion source,the beam emittance cannot satisfy the requiremen...Purpose High current beam is required for CSNS update in future.Over 50 mA H-will be designed to deliver to the linac in CSNSⅡ.For the present state of CSNS ion source,the beam emittance cannot satisfy the requirement of RFQ entrance at the 50 mA H-beam.In order to improve the beam quality,CSNS ion source is required further improvement.Methods Simulation shows emittance growth due to the space charge force in the intense H-beam when the beam transports through the analyzing magnet.After considering the neutralization of space charge,the emittance growth could be suppressed.The analyzing magnet thus is considered to removed,which might destroy the neutralization of space charge.The beam emittance is measured at the revised CSNS ion source.Results Measured results show that beam emittance without the analyzing magnet becomes smaller than that of CSNS ion source.At the requirement of 0.2πmm mrad,beam current is larger than 30 mA.It reveals that analyzing magnet could destroy space charge neutralization and result in the significant increase of emittance.Conclusions Although the results presented are preliminary,it is important to improve the beam quality.This paper details the ion source improvement and measurement process.展开更多
基金Supported by National Natural Science Foundation of China(11375162,10675104,51077119)
文摘We recently set up a time-resolved optical beam diagnostic system. Using this system, we measured the high current electron beam energy in the accelerator under construction. This paper introduces the principle of the diagnostic system, describes the setup, and shows the results. A bending beam line was designed using an existing magnetic analyzer with a 300 mm-bending radius and a 60° bending angle at hard-edge approximation. Calculations show that the magnitude of the beam energy is about 18 MeV, and the energy spread is within 2%. Our results agree well with the initial estimates deduced from the diode voltage approach.
文摘The control strategy is presented using passive and active hybrid magnetically suspended flywheels(P&A MSFWs),which can help meet the requirements of high precision and high stability for earth-observation satellites.Compared with the conventional flywheel,P&A MSFW has more rotation degrees of freedom(DOFs)since the rotor is suspended by magnetic bearings,and thus requires more efficient controllers.A modified sliding mode control law(SMC)to our novel nonlinear and coupled system is presented,which is interrupted by inertia matrix uncertainties and external disturbances.SMC law via Lyapunov method is improved,and a fuzzy control scheme is used to attenuate the chatting and control attitude accuracy and maintain the robustness of SMC.Simulation results are provided to illustrate the efficiency of our model by using our control law.
基金supported by the Program of National Natural Science Foundation of China Grant No.11875271
文摘Purpose High current beam is required for CSNS update in future.Over 50 mA H-will be designed to deliver to the linac in CSNSⅡ.For the present state of CSNS ion source,the beam emittance cannot satisfy the requirement of RFQ entrance at the 50 mA H-beam.In order to improve the beam quality,CSNS ion source is required further improvement.Methods Simulation shows emittance growth due to the space charge force in the intense H-beam when the beam transports through the analyzing magnet.After considering the neutralization of space charge,the emittance growth could be suppressed.The analyzing magnet thus is considered to removed,which might destroy the neutralization of space charge.The beam emittance is measured at the revised CSNS ion source.Results Measured results show that beam emittance without the analyzing magnet becomes smaller than that of CSNS ion source.At the requirement of 0.2πmm mrad,beam current is larger than 30 mA.It reveals that analyzing magnet could destroy space charge neutralization and result in the significant increase of emittance.Conclusions Although the results presented are preliminary,it is important to improve the beam quality.This paper details the ion source improvement and measurement process.