Field ion emission from thin tungsten wires covered with a layer from an etching procedure

The preparation of etched, thin tungsten wires which have a relatively smooth surface is described. Diameters as small as 1 μm have been reached. From the electrochemical etching procedure a thin layer of Ksub(x)(Wsub(y)Osub(z)) remains on the surface. Such wires have been used as field ion emitters and their ability to field-ionize gases of high ionization potential is demonstrated by their use in field ion microscopy and field ion mass spectrometry. (orig.)