Hydrogen ion production using carbon nanotube field emitter arrays

We have used micro-gated carbon nanotube field emitter arrays to produce hydrogen ions via two mechanisms; direct field ionization, and electron impact ionization. The changes in the fabrication process have improved the maximum emission current. The nanotubes are about 20nm in diameter (and so are likely multiwalled), and the gate electrodes are made of Cr. It is concluded that it should be possible to create very brief ion pulses using this method because the electron trajectory is short. Relatively long pulses will allow higher ionization rates. Because the arrays are small and the ion energy distribution is not too large, it should be possible to focus the ion beam to a spot size similar to the area of the array.