ION SOURCE FOR SECONDARY ION MASS SPECTROMETER

PURPOSE:To secure an ion source for a secondary ion mass spectrometer, capable of highly sensitive measurement, by installing a reagent feeding device which feeds an organic matter sample with a reagent at the time of ion source operation. CONSTITUTION:A primary beam discharged out of a primary beam source 2 spatters the organic sample coated on a sample holder 8 in an ionization chamber 4, while the formed secondary ion beam 10 is drawn out and led into a mass spectrometer 11 by way of an electrostatic lens 6 and an earth slit 7. At this time, an acid or basic reagent gas is sprayed to a reagent surface from a nozzle. This reagent gas is led from outside the ion source by a reagent gas intake pipe 12 and the connection part 18. When a solid acid is used, it is put in a reagent receiver 14, heated by a heater 16, and turned into a gas state, then led into the ion source. When this gasified reagent is used, it is led into the ion source from a gas cylinder or a gas receiver 17 through a valve.