Comparison of tips, thin wires and sharp metal edges as emitters for field ionization mass spectrometry

Abstract

The emission properties of tips, thin wires and edges of sharp blades in field ionization are compared. The field strengths at ideally smooth emitters are calculated. The emitting surface of a smooth blade is about two orders of magnitude smaller than that of a smooth wire at the same field strength under normal working conditions. It is shown that small field enhancing protrusions do not alter this ratio. It was found that the disadvantage of fragility of thin wires can be overcome in four different ways.