Design and Experiments of a 0.66-THz Short-Pulse TE14,5 Mode Second-Harmonic Gyrotron

Experimental investigations on a 0.66-THz gyrotron have been accomplished. Meanwhile, the magnetic injection gun and the gyrotron beam–wave interaction cavity are designed and optimized. The gyrotron cavity is a traditional three-section cavity. The experimental results demonstrate that this gyrotron is under the stable operation of the second cyclotron harmonic. The operating mode is TE
$_{\text {14, {5}}}$
mode and the pulselength is
$80 \mu \text{s}$
. By tuning the beam energy and the operating magnetic field, the maximum frequency of this gyrotron reaches 656.95 GHz and the output power is up to 282 W. Furthermore, this gyrotron can be utilized as a frequency-tunable source, the frequency-tunable range is about 70 MHz. This gyrotron is specially designed to meet the requirement of the experiment of irradiating THz waves on living bodies.