Carbon Nanotube Electron Gun (CNTeg)

Carbon Nanotube Electron Guns (CNTegs) are essential for the future of space exploration as they are 10 times more power efficient than current thermal electron guns. CNTegs are a part of electron emitters called cold cathodes, in this way they rely solely on electric fields and not on direct heating of a thermal filament. CNTegs also provide moderate current, which is quite useful for electron-impact ionization of neutrals in planetary atmospheres. Currently we are working on characterizing the energy of the electron beam. The above simulation represents this energy characterization of the CNTeg electron beam, where it is subject to various external voltages which bends the beam in accordance to the primary electron energy.

Field Electron Emission

Looking through the lens of the first electrode, which we call Gate 1 (G1) gives one a perspective of the quantum phenomena that generates the field emission, first predicted in 1928 by Fowler and Nordheim. When we provide a moderate voltage of say 100 volts, we are able to generate an electric field below G1 and above the black carbon nanotube square. The electric field can get as large as 1MV/meter, which is sufficient to accelerate primary electrons which are tunneled from the nanotubes themselves up into our electron gun. Then these primary electrons continue through G1, and on to the anode where they are collected at the next electrode. We are currently investigating the influence of charging we do not account for, as an example due to secondary electron emission from the tungsten wires on the G1 electrode .