The problem of optimizing devices of diffraction electronics

Previous studies have shown that it is possible to increase the efficiency of diffraction-electronic devices (specifically, distributed-interaction O-type devices) by an appropriate variation of the phase velocity of the wave that is synchronous with the electron beam. The present paper considers the problem of determining smooth phase-velocity variations which yield a maximum of the quality functional; the analysis takes into account the electron efficiency and the oscillator self-excitation conditions. It is noted that a smooth variation of the phase velocity over the length of the interaction space can be achieved through an appropriate change in the step of the diffraction grating.