Digital Linear Ion Trap Circuit Layout for Simpler Ion Ejection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional linear ion traps require complex power circuits to apply radio-frequency voltages with a phase difference and superpose excitation voltages, complicating the ion capture and ejection process.
Innovation Solution
A simplified power circuit for a linear ion trap is achieved by separating the rod electrodes into two sets, where one set applies radio-frequency voltage for capture and the other set applies resonance excitation voltage, eliminating the need for a 180-degree phase difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radio-frequency voltages with 180-degree phase difference are applied to both pairs of rod electrodes for ion capture, then ion capture function is achieved, but power circuit complexity increases
Solution Approach 1:
The four rod electrodes are divided into two functional groups: the first pair (X-axis) applies radio-frequency voltage for ion capture, while the second pair (Y-axis) applies excitation voltage for ion ejection. This segmentation allows independent control of capture and ejection functions, eliminating the need for complex phase-differentiated voltage application to both pairs simultaneously.
Solution Approach 2:
Each rod electrode pair can serve multiple functions depending on the applied voltage. The first rod electrode pair handles both ion capture (via radio-frequency voltage) and ion ejection (via excitation voltage), while the second pair complements these functions. This multi-functionality reduces the need for separate dedicated electrodes for each function.
2Reliability
If excitation voltage is superposed on radio-frequency voltage for resonance excitation, then ion ejection is achieved, but power circuit complexity increases
Solution Approach 1:
The excitation voltage is applied independently to the second pair of rod electrodes rather than being superposed on the radio-frequency voltage applied to the first pair. This segmentation simplifies the power circuit by eliminating the need for voltage superposition and phase control, while still achieving resonance excitation through the complementary electrode configuration.
3Reliability
If four rod electrodes are used to surround ion capture space, then ion capture capacity is improved, but electrode configuration complexity increases
Solution Approach 1:
Different pairs of rod electrodes are assigned different functional qualities: the first pair (X-axis) is optimized for radio-frequency voltage application for capture, while the second pair (Y-axis) is optimized for excitation voltage application for ejection. This local differentiation of electrode functions simplifies the overall configuration by giving each electrode pair a specific role rather than requiring all four to perform identical functions.
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 allows for a simpler power circuit design, facilitating efficient ion capture and ejection without the complexity of phase-differentiated voltage application.
Implementation Method 1
A mass spectrometer employing an ion trap which holds ions by an effect of an electric field
Implementation Method 2
an excitation voltage is superposed on the radio-frequency voltage applied to one pair of rod electrodes, to induce resonance excitation of an ion having a specific mass-to-charge ratio
Data Source
AI summary
In order to simplify a power circuit, a linear ion trap (2) according to the present invention includes: two first rod electrodes (21, 22) facing each other across a central axis (C), each of the first rod electrodes having an opening (21a, 22a); two second rod electrodes (23, 24) facing each other across the central axis, in a direction different from the direction in which the two first rod electrodes face each other; and a pair of end electrodes (25, 26) respectively arranged outside the two end faces of the two first rod electrodes and the two second rod electrodes. A controller (7) is provided to control a radio-frequency voltage supplier (4) which applies a radio-frequency voltage for capturing ions to each of the two second rod electrodes, and an excitation voltage supplier (5) which applies a voltage for resonance excitation to each of the two first rod electrodes.