Electrostatic Trap Ion Injection for Higher Space Charge Capacity
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Solution Overview
Problem
Existing electrostatic traps face limitations in space charge capacity and stability due to pulsed ion injection and potential ramping, leading to artifacts in mass spectra and reduced ion flux throughput.
Innovation Solution
A method of injecting a continuous ion beam into an electrostatic trap with static potentials for an extended period, allowing for prolonged ion filling and trapping, and using techniques like ion sharpening and multiplexing to enhance ion motion and detection, thereby improving space charge capacity and spectral analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pulsed ion injection is used, then ion packets can be formed with controlled size, but space charge capacity is limited and self-bunching occurs when more than 1E+4 ions are injected
Solution Approach 1:
The patent implements continuous ion beam injection instead of pulsed injection, allowing ions to be continuously introduced into the electrostatic trap throughout the oscillation cycle. This continuous injection method eliminates the space charge limitations of pulsed injection while maintaining controlled ion packet formation through the specific timing and positioning of the ion source relative to the trap's oscillation phases.
2Object-affected harmful factors
If potential ramping is applied during ion injection, then ion losses on trap walls are prevented, but mass accuracy deteriorates due to time variable power supply instability
Solution Approach 1:
The patent positions the ion source and injection optics to pre-align ions with the trap center before injection begins. The ion beam is injected at the optimal phase of the oscillation cycle, allowing ions to enter the trap at the correct position and velocity without requiring potential ramping. This preliminary positioning prevents wall collisions while maintaining stable potentials for accurate mass measurement.
3Measurement precision
If pulsed ion injection with 100 ns duration is used, then mass accuracy is optimized, but formation of ion packets with extended volume is complicated and space charge capacity is reduced
Solution Approach 1:
The patent utilizes the dynamic oscillation of ions within the electrostatic trap to naturally form extended ion packets. By continuously injecting ions during the oscillation cycle rather than using short pulses, the system allows ion packets to dynamically expand to optimal volumes while maintaining mass accuracy through the stable electrostatic field and precise injection timing.
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 approach significantly increases ion flux throughput, extends the duty cycle, and enhances mass spectral analysis by reducing higher harmonic signals and improving resolving power, allowing for more uniform and precise ion trapping and detection.
Implementation Method 1
Known electrostatic traps (E-traps) employ electrostatic fields for indefinite spatial confinement (trapping) of moving ions, and for arranging highly isochronous ion oscillations
Implementation Method 2
Ionic oscillation frequencies are detected by an image current detector
Data Source
AI summary
A method of mass spectral analysis in an analytical electrostatic trap (14) is disclosed. The electrostatic trap (14) defines an electrostatic field volume and includes trap electrodes having static and non-ramped potentials. The method comprises injecting a continuous ion beam into the electrostatic field volume.