Patent ID: 9460906
Filing Date: 2016-10-04
CPC Classification: H01J

Claim Text:
1. A method of guiding or trapping ions comprising: providing an ion guide or ion trap comprising a plurality of electrodes; applying an AC or RF voltage to at least some of said plurality of electrodes in order to confine radially at least some ions within said ion guide or ion trap; maintaining one or more DC, real or static potential wells or a substantially static inhomogeneous electric field along at least a portion of the axial length of said ion guide or ion trap in a first mode of operation; and maintaining a time varying substantially homogeneous axial electric field along at least a portion of the axial length of said ion guide or ion trap in said first mode of operation, wherein the electric field is varied with time so as to cause ions to oscillate axially along the ion guide or ion trap such that at least some ions are ejected from a trapping region of said ion guide or ion trap in a substantially non-resonant manner whilst other ions are arranged to remain substantially trapped within said trapping region of said ion guide or ion trap.