A 150–600 GHz step-tunable gyrotron

TLDR

The gyrotron was specifically optimized for second‑harmonic operation. The paper reports on the operation of a step‑tunable, low‑power, continuous‑wave gyrotron at its fundamental and second harmonic frequencies. The study observes single‑mode operation at the second harmonic and mode competition between the second harmonic and fundamental. The gyrotron can tune from 150 to 300 GHz at the fundamental and beyond 600 GHz via second‑harmonic operation, delivering over 20 W at the fundamental and hundreds of milliwatts at the second harmonic under 10 kV, 50 mA conditions.

Abstract

An account of the operation of a step-tunable, low-power, continuous-wave gyrotron, GYROTRON V, at the fundamental and second harmonic of the electron cyclotron frequency is presented. The design of this gyrotron was especially optimized for the second harmonic. The gyrotron operating frequency at the fundamental can be tuned from 150 to 300 GHz and extended by second-harmonic operation to above 600 GHz. Under normal operating conditions where the accelerating voltage is 10 kV and the beam current is 50 mA, power levels in excess of 20 W are obtained at the fundamental and hundreds of milliwatts at the second harmonic. The paper includes observations of single mode operation at the second harmonic and mode competition between second harmonic and fundamental.