Third-Harmonic 1 THz Large-Orbit Gyrotron With an Improved Quasi-Regular Cavity

A pulsed third-cyclotron-harmonic large-orbit gyrotron (LOG) operating with a radiation power of 0.4 kW at a frequency of 1 THz was implemented in 2008 in the 80 kV/0.7A/ $10~\mu \text{s}$ version. In this letter, we describe a new experiment carried out on the basis of this LOG, where a modified cavity with a reduced diffraction Q-factor and improved mode selectivity was used. This modification allowed to increase the output radiation power up to 1.3 kW, as well as to expand the range of parameters of the selective excitation of the operating high-harmonic wave.