Patent ID: 8022358
Filing Date: 2011-09-20
Classification: H01J

Abstract:
1. An ion guide or ion trap comprising: a plurality of electrodes; an AC or RF voltage supply arranged and adapted to apply an AC or RF voltage to at least some of said plurality of electrodes in order to confine at least some ions radially within said ion guide or ion trap; a DC voltage supply arranged and adapted to maintain a DC or electrostatic electric field across at least a portion of the axial length of said ion guide or ion trap in order to confine at least some ions axially within an axial ion trapping region of said ion guide or ion trap, wherein said DC or electrostatic electric field is substantially linear across a first portion of said axial ion trapping region and is substantially non-linear across one or more second portions of said axial ion trapping region; and a supplemental AC voltage supply arranged and adapted to apply a supplemental AC voltage or potential to said electrodes in a first mode of operation in order to resonantly or parametrically eject at least some ions axially from said ion guide or ion trap.