Abstract: The electron multiplier is of the kind in which a charge current is amplified by successive passage to and secondary emission of electrons from dynodes which are arranged in two opposed rows. The multiplier is arranged for application of electric charge to the dynodes so as to focus the charge current on to each of the dynodes in succession, alternating between the rows. The dynodes have electron emissive surfaces to which the charge current passes and angled flanges located at opposite edges of the surfaces. The surfaces are preferably formed by aluminum foil. The rows of dynodes are preferably formed by aluminum foil. The rows of dynodes are supported on opposed cantilevered insulating members by crimped straps.

Abstract: A plasma discharge ion source for a mass spectrometer, having a magnet forming an axial magnetic field, two cathodes axially spaced in said field and an annular anode between the cathodes. Ions generated by the source emerge via an opening in one cathode and then pass in succession through axially aligned openings in two planar electrodes. The electrode closest said one cathode has a further disc or cone shaped electrode positioned in the opening of that electrode so as to form an annular gap between the peripheries of the disc shaped electrode and opening.Ions from the source opening pass in succession through the annular gap and then through the electrode opening in the electrode furtherest from the source opening. By applying suitable electric potentials to the electrodes ions of an energy above a predetermined level are prevented from passing through the electrodes.

Abstract: Electron Multiplier in which the charge current is conformed by an electrostatic field to pass in alternating fashion between successive dynode surfaces of two opposed rows, the dynodes of one row being on outer surfaces of coaxial cylindrical elements and the dynodes of the other row being on inner surfaces of surrounding annular elements.