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In this paper, we describe the design and development of helical cut smooth wall mode launcher for high frequency and high power Gyrotron. A Vlasov-type helical cut mode launcher for converting TE 22,6 mode to a Gaussian mode has been designed for 120 GHz, 1 MW Gyrotron. The initial design of mode launcher has been optimized using LOT/SURF-3D software. The mode launcher diameter and length are optimized considering the minimum return loss and the minimum insertion loss by using CST microwave studio. The return loss (S 11 ) and insertion loss (S 21 ) performance of helical cut smooth wall mode launcher have been obtained using CST-Microwave Studio. The fabrication of Vlasov-type helical cut mode launcher for 120 GHz Gyrotron has also been carried out. [ABSTRACT FROM AUTHOR]

Highlights: [•] Numerical analysis of gyrotron cavity geometry effect on Q value, ohmic wall heating and field profile. [•] Experimental analysis of gyrotron cavity geometry effect on Q value, ohmic wall heating and field profile. [•] Effect of gyrotron cavity geometrical parameters on the start oscillation current. [•] Effect of gyrotron cavity geometrical parameters on the beam–wave interaction efficiency. [ABSTRACT FROM AUTHOR]

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]