Switchable-Path Ion Guide Using RF Surface and DC Gradient

The ion guide is segmented into multiple discrete ion paths (first ion path to second ion transport aperture, second ion path to third ion transport aperture) that can be independently controlled. This segmentation allows the system to direct ions to different analysers or bypass slow sections without requiring a completely complex redesign, as each path can be activated or deactivated independently through the DC gradient control.

The system dynamically switches between different ion paths by adjusting the DC gradient voltage. The DC potential source can change the electric field configuration in real-time, allowing ions to be directed along different trajectories based on operational requirements. This dynamic control enables versatile ion path configuration without mechanical moving parts, reducing mechanical complexity.

The patent transitions from two-dimensional narrow channel confinement to three-dimensional volume trapping by utilizing the full spatial capacity of the ion guide. The DC gradient confines ions in one dimension while the radio frequency field provides confinement in perpendicular dimensions, creating an effective three-dimensional trapping volume. This allows ions to travel through a larger effective path length without experiencing the severe space charge effects that would occur in narrow two-dimensional channels.

The system employs a composite electromagnetic field structure combining DC and radio frequency fields. The DC gradient provides linear confinement along the ion path, while the radio frequency field creates a pseudopotential well that prevents ion beam expansion. This composite field approach effectively manages space charge effects while maintaining efficient ion transport, achieving both fast transit times and high transmission efficiency.

The radio frequency field acts as an intermediary that mediates between the expanding ion beam and the physical boundaries of the ion guide. Instead of allowing ions to directly contact electrodes and lenses, the radio frequency pseudopotential field creates a virtual confinement boundary that keeps the ion beam contained within the usable volume. This intermediary field prevents contamination while accommodating the natural expansion of the ion beam due to space charge effects.

The patent replaces mechanical physical barriers (such as narrow channels or tight apertures) with an electromagnetic field-based confinement system. The DC gradient and radio frequency field together create an invisible but effective boundary that guides ions without requiring physical contact with channel walls or electrodes. This substitution eliminates the contamination problem associated with mechanical confinement while maintaining reliable ion transmission.