Here is an example of a radially flange mounted ion guide.
An additional ion guide could be mounted on the other side of the conductance limit.
As well, the plane of the conductance limit can be moved to any position along the 'z' axis, from directly inside the radial flange, to re-entrant into either side.
If one were to create a gate-valve electrode, we would start with a solid flange and bore out the middle from one side.
