Measured performance of magnetron injection guns for gyrotrons
Magnetron injection guns (MIGs) are a principle component in gyrotrons and gyroklystrons. The performance of the RF device critically depends on the performance of the MIG that provides the electron beam. Unfortunately, recent measurements indicate that MIGS often generate asymmetrical electron beams that can adversely impact the operation of the RF source. This presentation will describe the measurement facility and provide results from recent tests.
Experimental study of gyrotron efficiency enhancement by improvement of electron beam quality
The methods for suppressing parasitic low- frequency oscillations (LFOs) have been applied to improve electron beam quality in a 4-mm 100-kW gyrotron. In the conditions of suppressed LFOs and of high cathode emission uniformity, the stable operation of this gyrotron at pitch factor values high than 1.5 has been achieved. As a result, the efficiency of the gyrotron at the main TE12,3 mode has been increased from 32 % (corresponds to the designed regime with pitch factor of 1.28) up to 42 %.
On potentials of gyrotron efficiency enhancement: measurements and simulations on a 4-mm gyrotron
In a 74.2-GHz 100-kW pulse gyrotron, the characteristics of parasitic low-frequency oscillations and their influence on electron energy spread have been determined. A method for suppressing parasitic oscillations by varying the magnetic field distribution in the beam compression region is studied. The results of measurements demonstrate the influence of azimuthal inhomogeneity of electron emission on the excitation of parasitic oscillations and on the gyrotron output parameters. Obtained data allows one to determine the ways of gyrotron efficiency enhancement by improved quality of the helical electron beam