A 40 A triode type magnetron injection gun for a 1 MW, 120 GHz gyrotron has been designed. The preliminary design has been obtained by using some trade-off equations. Computer simulation has been performed by using the commercially available code EGUN and the in-house developed code MIGANS. The operating voltages of the modulating anode and the accelerating anode are 60 kV and 80 kV, respectively. The operating mode of the gyrotron is TE22,6 and it is operated in the fundamental harmonic. The electron beam with a low transverse velocity spread (δβ⊥max = 3.3%) and velocity ratio, α = 1.38 at beam current = 40 A is obtained. The simulated results of the MIG obtained with the EGUN code have been validated with another trajectory code TRAK. The results obtained from both the codes are in good agreement. The sensitivity study has been carried out by changing the different gun parameters to decide the fabrication tolerance.
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