A new approach to gas field ion sources

Ultramicroscopy. 2003 May-Jun;95(1-4):183-8. doi: 10.1016/s0304-3991(02)00315-7.

Abstract

A new approach to gas field ion sources is described. It is based on a structure made by inserting a field emission tip inside a small diameter tube. The tube supplies gas to the tip from a high-pressure chamber into a high-vacuum chamber where ionization takes place. Comparison of projection electron and ion micrographs shows that ionization results from a field ionization process taking place at the very end of the tip. Emission currents in the 10nA range, for a few kV emission voltages, are obtained with various gases including neon, air and hydrogen. Lifetime experiments with H(2) show stable emission for days.