The thermionic electron sources have the disadvantage of using consumables (filaments, cathodes) which have relatively short lifetimes. To solve this problem, Leptons-Technologies has designed patented sources of low plasma gaseous electrons.
These sources use a magnetic field and a microwave to heat the electrons until they can ionize the molecules of a neutral gas. The ECR plasma cavity serves as a source of electrons from which the beam will be extracted. For the electron beams, the cavity is brought to a negative potential and has a hole allowing the electrons to escape from the cavity through an electric field applied to the output of the cavity.