The point emitter as a positive-ion source

Abstract

A needle-shaped tungsten "point" filament has been used as a positive ion source. Hydrogen ions were produced experimentally at room temperature from the point emitter under the effect of high electric fields. The electron field-emission microscope is recommended as a tool to augment data on adsorption, migration, and vaporization charac-teristics of the heavier elements. The preferential transfer of Cm242 as ions from an emitter point at 1600°K was observed. The point e-mitter is shown to be a source of positive ions for solid samples. Application of point-emitter techniques to mass spectroscopy is considered probable upon solution of the sample-replenishment problem . ii