Field desorption point source of alkali and alkaline-earth metal ions

A field desorption point source of metal ions is explored A continuous or pulse flux of Na,Cs and Ba ions from the W and Ir field emitter is achieved. The continuous flux of ions is realized when under certain conditions surface diffusion flux of adatoms to the apex of a tip is equal to desorption flux. The ion current was 0.001 - 0.1 nA. The ion current density in pulse (10 ns) amounted to 10(3) A/cm(2). Size of emission area con be changed from similar to 1 mcm to similar to 1 nm by varying conditions of desorption. The point source of metal ions can be used in ultra hight vacuum instalations.