Formation of an Annular Electron Beam for Subterahertz Gyrotrons Using an Electron-Optical System With a Multitip Field Emitter

The patterns of electron beam formation by an electron-optical system (EOS) with a multitip field emitter have been studied both experimentally and with the help of numerical modeling. This article considers the distribution of electrons in the beam along transverse and longitudinal velocities, which are necessary for the development of EOS. The achievable output parameters of radiation generation have been determined when installing an EOS with a field emitter in a gyrotron operating at a frequency of 140 GHz. This system provides an electron beam with the currents of approximately up to 60 mA and operates stably at the typical technical pressures of about 10
$^{-\text{7}}$
torr.