Repetitively Pulsed Relativistic Cherenkov Microwave Oscillator Without a Guiding Magnetic Field

TLDR

The study demonstrates a magnetic‑field‑free Cherenkov microwave oscillator operating in repetitively pulsed modes at 0.5 and 1.2 MeV, and investigates the lifetime of velvet‑covered cathodes and anode grids under these conditions. The oscillator achieved 8–16 % efficiencies (0.2–2.5 GW peak power) at 1 Hz and 7–15 % efficiencies (0.17–2.0 GW peak power) at 10 Hz, with anode grid and cathode lifetimes of ~3000 pulses at 1.2 MeV and >11 000 pulses at 0.5 MeV.

Abstract

Repetitively pulsed modes of operation of a Cherenkov microwave oscillator without an external magnetic field for the electron energies of 0.5 and 1.2 MeV were realized in the experiment. In a batch mode with a 1-Hz repetition frequency, the oscillator efficiencies (taking into account the total diode current) were 8% ±2% and 16% ±3 %, respectively (at 0.2 ±0.04-GW and 2.5 ±0.5-GW peak generation power, respectively). For a batch mode with a 10-Hz repetition frequency, the corresponding efficiencies were 7% ±1% and 15% ±3%, respectively (at 0.17 ±0.03-GW and 2.0 ±0.4-GW peak generation power, respectively). Investigations of the lifetime of velvet-covered cathodes and anode grids of oscillators were carried out in repetitively pulsed modes. The lifetime of the anode grid and velvet-covered cathode for the electron energy of 1.2 MeV was about 3000 pulses, and for the electron energy of 0.5 MeV, it can exceed 11 000 pulses.