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We propose the design of a dual-anode electron gun, so named due to the presence of an additional electrode, namely, the control anode in the vicinity of the cathode in addition to the ion-barrier anode and the ground anode. We found the potential of the control anode to play an important role in enhancing the life of a space traveling-wave tube. By a telemetric command, one could control the control anode potential with a view to enhancing the cathode current that would otherwise deteriorate with the progress of time. Further, due care was taken in the thermal design by providing a heat shielding of the cathode of the proposed dual-anode gun to ensure that the cathode, which is operated at a lower temperature for a longer cathode life, does not further suffer a decrease in temperatures due to heat dissipation. Furthermore, to compensate for the deterioration of the cathode current with the progress of time, we propose the application of a nominal change in the control anode potential by a telemetric command. The electrostatic and thermal simulations of the proposed dual-anode gun were carried out by the commercial simulation codes EGUN and ANSYS, respectively. The paper presents the effect of heat shield thickness and material property on the cathode temperature as well as the effect of the structural deformation caused by the axial and radial expansion of the cathode on electron beam optics, a demountable dual-anode gun was set up for validating the cathode temperature against simulation. [ABSTRACT FROM PUBLISHER]

A triode-type magnetron injection gun (MIG) for a 42 GHz, 200 kW gyrotron was designed by two commercial codes: EGUN and TRAK. An in-house code MIGANS was used as the post-processor of the EGUN. Some basic equations relevant to the problem available in literature were used while using the EGUN code for the purpose. The results on the design output parameters obtained by these two codes were found to be in close agreement. [ABSTRACT FROM AUTHOR]

Highlights: [•] The complete electrical design of 42GHz, 200kW gyrotron is presented. [•] Un-depressed collector and axial output system for RF power is selected. [•] Various commercially available design tools as well as in-house developed computer codes are used in the design process. [•] The experimental results of cold cavity analysis are also presented. [•] The design results show more than 200kW power with 40% interaction efficiency at 42GHz frequency. [Copyright &y& Elsevier]

Abstract: The electrical design of different components of 1MW, 170GHz gyrotron such as, magnetron injection gun, cylindrical interaction cavity and collector and RF window is presented in this article. Recently, a new project related to the development of 170GHz, 1MW gyrotron has been started for the Indian Tokamak. TE34,10 mode is selected as the operating mode after studied the problem of mode competition. The triode type geometry is selected for the design of magnetron injection gun (MIG) to achieve the required beam parameters. The maximum transverse velocity spread of 3.28% at the velocity ratio of 1.34 is obtained in simulations for a 40A, 80kV electron beam. The RF output power of more than 1MW with 36.5% interaction efficiency without depressed collector is predicted by simulation in single-mode operation at 170GHz frequency. The simulated single-stage depressed collector of the gyrotron predicted the overall device efficiencies>55%. Due to the very good thermal conductivity and very weak dependency of the dielectric parameters on temperature, PACVD diamond is selected for window design for the transmission of RF power. The in-house developed code MIGSYN and GCOMS are used for initial geometry design of MIG and mode selection respectively. Commercially available simulation tools MAGIC and ANSYS are used for beam–wave interaction and mechanical analysis respectively. [Copyright &y& Elsevier]

Abstract: In this paper, the three-dimensional simulation of triode-type magnetron injection gun (MIG) for 120GHz, 1MW gyrotron is presented. The operating voltages of the modulating anode and the accelerating anode are 57kV and 80kV respectively. The high order TE22,6 mode is selected as the operating mode and the electron beam is launched at the first radial maxima for the fundamental beam-mode operation. The initial design is obtained by using the in-house developed code MIGSYN. The numerical simulation is performed by using the commercially available code CST-Particle Studio (PS). The simulated results of MIG obtained by using CST-PS are validated with other simulation codes EGUN and TRAK, respectively. The results on the design output parameters obtained by using these three codes are found to be in close agreement. [Copyright &y& Elsevier]