In one embodiment, a miniaturized structure and associated method function as a mass spectrometer or analyzer and may, with modification, function as an ion generator. The miniaturized structure has a pair of generally planar parallel spaced electrodes which have projecting walls cooperating to define an ion generating chamber and an exit aperture. By controlling the electric field which is oriented perpendicular to an applied magnetic field, the ion beam may be separated into a plurality beams based upon mass to charge ratio emerging from the exit of the apparatus and when the apparatus is functioning as a mass spectrometer or analyzer impinges on an ion collector which responsively transmits information to a cooperating processor. Where it is desired to have it function as an ionizer the ion collector disposed adjacent the ion exit is eliminated.