Ion microprobe using a field evaporation ion source fed by liquid gallium. [For finding the location of specific stable isotopes in samples]

A scanning ion microprobe with a resolution of 15 nm or better appears to be quite possible on the basis of a field-evaporation (EHD) ion source that has been developed and a high efficiency system for production and collection of negative secondary ions. The possibilities of still better systems for the analysis of the secondaries using either stopping-power or laser-induced-fluorescence methods of identification are discussed briefly.