Improvement of electron beam quality and gyrotron efficiency by optimization of electric field distribution in the gun region

A technique for controlling electric field distribution in the near-cathode region of a magnetron-injection gun has been developed. The possibility to improve the quality of the helical electron beam by regulated non-uniformity of electric field is studied experimentally and using computer modelling. This technique is applied to enhance the efficiency of a 74.2 GHz, 100 kW gyrotron.