Electrostatic Ion Trap Pickup Electrode Harmonic Suppression
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Solution Overview
Problem
Existing electrostatic ion trap technologies face challenges in deciphering the frequency spectrum of trapped ions undergoing non-harmonic oscillations, particularly when dealing with a wide range of ion masses, as higher order harmonics often overlap, leading to complex frequency spectra and requiring extensive computational resources or multiple electrodes, which can deteriorate the signal-to-noise ratio.
Innovation Solution
The apparatus configures pickup electrodes to detect trapped ions such that the time separation between signal pulses is approximately equal to 2π + 12nfsig(m), where n is an integer, effectively suppressing predetermined harmonics without complex computational steps, thereby simplifying the frequency spectrum and enhancing mass resolving power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pickup electrodes are used to eliminate harmonics from the frequency spectrum, then the mass resolving power is improved, but the device complexity and signal-to-noise ratio deteriorate
Solution Approach 1:
The patent changes the temporal parameter of signal detection by precisely controlling the time separation between signal pulses detected by the pickup electrode. By setting the time separation to specific values (e.g., T/2, T/3 where T is the signal period), the apparatus selectively suppresses unwanted harmonics in the frequency spectrum, achieving high mass resolving power without requiring multiple electrodes or complex signal processing systems
2Measurement precision
If linear combination method is used to eliminate harmonics, then the mass spectrum can be obtained, but the signal-to-noise ratio deteriorates and device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the pickup electrode to detect signal pulses with specific time separations that inherently suppress unwanted harmonics before the signal is processed. This preventive approach eliminates harmonics at the detection stage rather than requiring post-detection signal processing, thereby maintaining high signal-to-noise ratio while achieving accurate mass spectrum
3Measurement precision
If higher order harmonics are used for mass analysis, then the mass resolving power increases, but the frequency spectrum becomes more complex due to harmonic overlap
Solution Approach 1:
The patent converts the harmful effect of harmonic overlap into a beneficial feature by using the time separation control to selectively suppress unwanted harmonics. The very harmonics that would normally cause spectral complexity are eliminated through precise temporal gating, allowing higher order harmonics to be used for mass analysis without the detrimental overlap effects
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 the suppression of specific harmonics, reducing computational complexity and maintaining a high signal-to-noise ratio, enabling more accurate mass spectrometry without the need for extensive post-processing, especially for non-harmonic oscillatory motion in electrostatic ion traps.
Implementation Method 1
an electrostatic ion trap configured to trap ions such that the trapped ions undergo oscillatory motion in the electrostatic ion trap
Implementation Method 2
an image charge/current detector configured to obtain an image charge/current signal representative of trapped ions undergoing oscillatory motion
Data Source
AI summary
An apparatus configured to produce an image charge/current signal representative of trapped ions undergoing oscillatory motion. The apparatus includes: an electrostatic ion trap configured to trap ions such that the trapped ions undergo oscillatory motion in the electrostatic ion trap; an image charge/current detector configured to obtain an image charge/current signal representative of trapped ions undergoing oscillatory motion in the electrostatic ion trap, wherein the electrostatic ion trap configured to trap ions such that the image charge/current signal in the time domain repeats, for ions of a given mass/charge ratio m, at a frequency fsig(m) [Hz] with a signal period Tsig(m) [s]. The image charge/current detector includes one or more pickup electrodes configured to obtain the image charge/current signal. The one or more pickup electrodes are arranged to detect two signal pulses caused by ions having the given mass/charge ratio m within each signal period Tsig(m). The one or more pickup electrodes are further arranged such that the time separation Δtsep(m) between the two signal pulses caused by ions having the given mass/charge ratio m within each signal period Tsig(m) is approximately equal to 2p+1/2.n.fsig(m) so as to suppress a predetermined nth harmonic within the image charge/current signal, where n is an integer that is 1 or more, and where p is an integer that is 0 or more.