DESIGN STUDY OF A 42/84 GHz, 500 kW, CW DUAL FREQUENCY REGIME GYROTRON

Abstract

In present work, conceptual design of CW 42/84 GHz dual regime gyrotron with 1ower level of 500 kW is stated. Using mode selection and mode competition procedure various mode-pairs are examined and the best mode-pair is chosen with consideration of various physical parameters and starting current plots. TE7,3 and TE12,6 modes are chosen for 42 GHz and 84 GHz operation respectively. Magnetic guidance system is designed which consists of super-conducing magnets to provide necessary magnetic field (1.6 T for 42 GHz and 3.28 rç for 84 GHz) at the center of gyrotron interaction cavity. By changing the position, physical dimensions and number of turns of the coils desired magnetic field profile is achieved. Triode type MIC is designed and optirriized using ESRAY codes to generate an annular electron beam of optimum properties. This gyrotron is designed with conventional cavity gyrotron which includes interaction section with weak input and output taper sections. Output system of gyrotroni is also designed that consists of a non-linear taper followed by a quasi-optical launcher and a RF-window. Various software packages are used to design different parts, like Gyrotron Design Suit V. 01 (GDS V. 01) for gyrotron cavity interaction calculation and RF window design and launcher optimization tool (LOT) and Surf3D for quasi-optical launcher design. Output of 500 kW power is achieved with efficiency of nearly 30% with TE7,3 mode at 42 GHz frequency and with TE12,6 mode at 84 GHz frequency. Results of RF- 101 behavior justified the reliability and the feasibility of this dual reginie Gyrotroni.