Patent ID: 8148679
Filing Date: 2012-04-03
Classification: H01J

Abstract:
1. An ion transfer arrangement for transporting ions between a relatively high pressure region and a relatively low pressure region, comprising: an ion transfer conduit having an inlet opening towards a relatively high pressure chamber, an outlet opening towards a relatively low pressure chamber, and at least one sidewall surrounding an ion transfer channel, the sidewall extending along a central axis between the inlet end and the outlet end; an evacuable chamber which encloses the ion transfer conduit; a plurality of apertures formed in the longitudinal direction of the sidewall of the conduit; and a pumping means for evacuating the evacuable chamber so as to remove a portion of the gas within the ion transfer channel through the plurality of apertures in the conduit to the evacuable chamber, the pumping means being configured to evacuate the evacuable chamber to a pressure below atmospheric pressure but high enough to maintain a viscous flow of gas and ions through the ion transfer channel.