The efficiency of a pitron

A technique is proposed for the calculation of the electron efficiency of a pitron, a self-oscillator that is based on a double-gap cavity and operates on the π-mode oscillations. For six generation zones, the parameters of grid gaps are optimized to ensure the maximum efficiency. Recommendations on the recalculation of the grid-gap parameters to the parameters of gridless gaps are formulated. It is shown that the total electron efficiency grows with the zone number from 14% for the zero zone to 65% for the fifth one. For practical application, it is recommended to employ the first and second zones with an electron efficiency of about 50% and 60%, respectively.