Patent ID: 8440964
Filing Date: 2013-05-14
Classification: H01J

Abstract:
1. A device for transporting ions along a longitudinal direction in an elevated gas pressure region, comprising: a multipole ion guide having a set of rods positioned along the longitudinal direction on an inscribed diameter equal to or less than 3.5 mm, said set having an entrance and an exit for the ions; a voltage source which provides alternating voltages applied to at least a subset of the rods to create a trapping field in a transverse direction; a conductance limit having an opening d placed at the exit of the multipole ion guide, the conductance limit separating the elevated gas pressure region having a molecular mean free path of λ from a low gas pressure region; wherein a converging continuum gas flow is provided through said conductance limit which transfers the ions collimated near a center of said ion guide into said low gas pressure region.