Ring Stack Ion Accelerator Field Homogenization
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Solution Overview
Problem
In mass spectrometry, ring stacked accelerators face challenges in maintaining a homogeneous electric field, especially when the field switches on and off, leading to variations in ion acceleration and decreased resolving power due to parasitic capacitances and time-dependent charging, which affect the precision of ion focusing and mass calibration.
Innovation Solution
The implementation of a single compensation capacitor and careful selection of capacitance values to create a capacitor voltage divider in parallel with the resistor voltage divider, ensuring equal electrical impedances across plates and compensating for parasitic capacitances, results in a more uniform electric field and improved RF performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electric field switches on and off rapidly in the ring stacked accelerator, then the time-of-flight mass spectrometry can be performed with pulsed ions, but the field homogeneity deteriorates due to parasitic capacitances and time-dependent charging
Solution Approach 1:
The patent applies preliminary action by pre-charging the field homogenization plates through a resistive voltage divider network before the rapid switching phase. This initial charging establishes a baseline voltage distribution that compensates for parasitic capacitances, ensuring that when the field switches on and off rapidly, the voltage division remains accurate and field homogeneity is maintained throughout the pulsed operation cycle
Solution Approach 2:
The patent implements feedback through the resistive voltage divider network connected to the field homogenization plates. The resistors provide a feedback path that continuously adjusts the voltage distribution across the plates during switching operations, counteracting the effects of parasitic capacitances and time-dependent charging to maintain consistent field homogeneity across multiple pulse cycles
2Ease of operation
If the plate spacing Z is increased to allow ion passage, then the accelerator can accommodate ion trajectories, but the field penetration from edges increases and destroys field homogeneity
Solution Approach 1:
The patent introduces field homogenization plates as intermediary elements between the main accelerator plates. These intermediate plates are connected through resistive voltage divider networks that actively compensate for edge effects and field penetration. The intermediaries create a buffered transition zone that maintains field homogeneity while allowing adequate spacing for ion passage through the accelerator structure
3Ease of manufacture
If Ohm's law is applied to the voltage division in the ring stacked accelerator, then the voltage division can be calculated using resistance values, but the calculation becomes inaccurate during rapid switching due to capacitive effects dominating
Solution Approach 1:
The patent applies parameter changes by transitioning from purely resistive parameter considerations to combined resistive-capacitive parameter optimization. The resistive voltage divider network is designed with specific resistance values that, when combined with the inherent capacitances of the accelerator structure, create a balanced RC network. This allows accurate voltage division during rapid switching by accounting for both resistance and capacitance effects in the voltage distribution calculation
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 solution enhances the homogeneity of the electric field within the ring stacked accelerator, leading to better time-of-flight mass analysis with improved mass resolution and reduced variations in ion flight times, resulting in higher precision and fidelity in ion detection.
Implementation Method 1
the voltage division will depend mostly on the capacitance values between all the plates and between the plates and the surrounding environment
Implementation Method 2
compensating for parasitic capacitances
Implementation Method 3
the potential can be applied to the field homogenization plates by a resistive voltage divider network. In this mode, Ohms law will apply
Implementation Method 4
The targeted atoms or molecules are ionized and introduced into a mass spectrometer in the gas phase. The ionized atoms or molecules (ions) are separated according to their charge-to-mass ratio
Implementation Method 5
ions are subjected to constant energy acceleration
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A ring stacked accelerator for use in a mass spectrometer includes a plurality of ring shaped plates arranged in a stack and is electrically coupled to a voltage divider that allows a substantially homogeneous electric field to be produced when the stack is energized. The voltage divider can include resistors and capacitors, where the capacitors are chosen to compensate for parasitic capacitances experienced by the plates. The ring stacked accelerator can be energized using an RF pulse. The ring stack accelerator can include one or more balancing capacitors for correcting effects that cause nonlinearity.