Segmented Ion Guide With Out-of-Phase RF Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ion guide devices face challenges in efficiently transmitting ions while minimizing ion heating and dissociation, particularly at higher pressures, due to strong gas flows and complex structures that affect sensitivity and manufacturing complexity.
Innovation Solution
An ion guide device with parallel ring electrodes, each comprising multiple electrode units, applies out-of-phase radio-frequency voltages and direct-current voltages to create a focused ion-confine field, reducing oscillations and dissociation by balancing radio-frequency and direct-current components, and optimizing electrode geometry for efficient ion transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If radio-frequency voltage with different phases is applied on adjacent segmented electrodes along the central axis to focus ions, then ion focusing is achieved, but ions oscillate near the inner surface causing heating and dissociation
Solution Approach 1:
The patent inverts the conventional phase assignment approach: instead of applying different phases to adjacent electrodes along the axis (which causes oscillations), it applies the same phase to adjacent axial electrodes while applying different phases to electrodes around the ring. This inversion of the phase gradient direction confines ions to the central region without oscillations against the wall, solving the heating problem while maintaining focusing capability.
2Productivity
If ion funnel structure is used to transmit and focus ions at high pressure, then sensitivity is increased, but strong gas flow increases vacuum pump load and brings noise to ion detection
Solution Approach 1:
The patent segments the continuous ion guide structure into multiple discrete ring electrodes with axial segmentation. This segmentation allows independent voltage control of each segment, enabling the creation of virtual barriers and electric field gradients that guide ions through pressure transitions more efficiently, reducing gas flow requirements while maintaining high transmission.
Solution Approach 2:
The patent implements dynamic voltage control where each ring electrode can be independently biased with different DC and radio-frequency voltages. This dynamic control allows the electric field configuration to be optimized for different operating conditions, enabling efficient ion guidance through varying pressure regions and reducing the need for high gas flow rates.
3Length of moving object
If small radius electrode array is used for ion transmission, then ion beam radius is reduced, but radio-frequency barrier at the edge becomes strong making it difficult for ions to enter
Solution Approach 1:
The patent applies local quality by creating spatially varying electric field characteristics through independent voltage control of each ring electrode. The radio-frequency voltage amplitude and phase can be locally adjusted at different axial positions and angular positions, allowing the barrier height to be optimized locally - lower at entry regions to facilitate ion entry, and higher at transmission regions to maintain tight focusing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively confines and focuses ions, improving transmission efficiency and reducing dissociation, while simplifying manufacturing and reducing the complexity of the ion guide structure.
Implementation Method 1
an radio-frequency voltage source used to apply out-of-phase radio-frequency voltages to adjacent electrode units belonging to the same ring electrode, and apply in-phase radio-frequency voltages on adjacent electrode units in the axial direction, thereby forming an ion-confine radio-frequency multipole field in the ion guide device
Implementation Method 2
a direct-current voltage source used to apply direct-current voltages to the plurality of ring electrodes, a direct-current voltage has a first direct-current component having amplitude that changing in an axial direction and a second direct-current component having amplitude that changing in a predetermined direction along a plane of the ring electrode
Implementation Method 3
the ions are transmitted off-axis and focused to a position closer to an inner surface of the ring electrode under a combined action of the radio-frequency voltages and the direct-current voltages
Data Source
AI summary
An ion guide device includes a plurality of ring electrodes disposed in parallel, wherein each ring electrode includes at least 4 electrode units separated from each other, a channel for ion transmission is formed inside the plurality of ring electrodes, and an arrangement direction of the plurality of ring electrodes defines an axial direction of ion transmission; an radio-frequency voltage source, for applying out-of-phase radio-frequency voltages on the neighboring electrode units belonging to the same ring electrode, and applying in-phase radio frequency voltages on a neighboring electrode units along the axial direction, thereby forming an radio-frequency multipole field that confine ions in the ion guide device; and a direct-current voltage source, wherein the ions are transmitted off-axis and focused to a position closer to an inner surface of the ring electrode under a combined action of the radio-frequency voltage and the direct-current voltage.