Point ion sources of Pt and Ir

High temperature field evaporation was used for creation of point ion sources of Pt and Ir ions. Field ion desorption microscopy was used for visualization of ionic beams in situ. It is typical both for Ir and for Pt to form a faceted built-up form with sharp vertexes in <023> directions as a result of a certain thermo-field treatment. The ion field evaporation beams from these vertexes were narrow and intensive enough and simultaneously geometrically stable. Details of formation and emission of such vertexes as well as some other forms are discussed.