Electron Flows Formed by Electron-Optical Systems Using Composite Field Emitters Made of Thermally Expanded Graphite and Diamond–Graphite Mixtures

Composite cathodes prepared according to an original technique from thermally expanded graphite (TEG) as well as from a mixture of diamond granules with particles of TEG (diamond–graphite cathodes) were studied. Regularities in the formation of electron beams by electron-optical systems (EOSs) with such cathodes were studied. The tested composite cathodes make it possible to obtain emission currents up to approximately 70–80 mA from an emitting surface area of 0.04–0.05 cm2, sufficient to ensure the operation of some types of subterahertz microwave devices, including spectroscopic gyrotrons.