Patent ID: 7351964
Filing Date: 2008-04-01
Classification: H01J

Abstract:
1. A modified ion funnel that extends the m/z range and the efficiency of transmission of ions in mass spectrometry analysis, comprising: an ion funnel having one or more electrodes disposed in succession with a terminal electrode disposed immediately following said one or more electrodes with co-axially aligned apertures, said terminal electrode having an aperture smaller than any electrode preceding it in said ion funnel; a conductance limiting electrode co-axially aligned with, and disposed immediately following, said terminal electrode of said ion funnel, said conductance limiting electrode defining an aperture that is smaller than any other aperture of said ion funnel; at least one compensation electrode co-axially aligned with, and disposed immediately following, said conductance limiting electrode, said at least one compensation electrode defining an aperture that is larger than the aperture of said conductance limiting electrode, wherein said at least one compensation electrode generates an electric potential adapted to deliver preselected on-axis and off-axis potential distributions at apertures of said one or more electrodes, said terminal electrode, said conductance limiting electrode, and/or said at least one compensation electrode; and whereby said preselected potential distributions extend the m/z range, the operational pressure range, and/or the efficiency of transmission of ions to a subsequent differential pumping stage or to a mass spectrometer.