Apertured Ion Detector Electrode for Stable Pulse Height Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ion detectors for mass spectrometers face challenges in accurately quantifying ions due to signal variations caused by secondary positive ions generated during ion collisions, leading to broad pulse height distributions and reduced signal-to-noise ratios, especially at low ion masses.
Innovation Solution
Incorporating an apertured electrode that allows secondary positive ions to pass through its apertures, preventing them from contributing to the detected signal, while ensuring first electrons generated by primary ions are detected by an electron detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If secondary positive ions are allowed to impact detector surfaces, then ion detection can be performed, but signal variation increases and signal-to-noise ratio decreases
Solution Approach 1:
The patent extracts and removes secondary positive ions from the detection path using an apertured electrode. The electrode allows primary ions to pass through to the dynode while blocking secondary positive ions from reaching detector surfaces where they would generate spurious electrons. This separation resolves the contradiction by eliminating the harmful effect of secondary ions without compromising primary ion detection capability.
Solution Approach 2:
The apertured electrode acts as an intermediary component between the dynode and the electron detector. It mediates the passage of ions by allowing primary ions to reach the dynode while preventing secondary positive ions from causing harmful effects downstream. This intermediary structure enables the system to maintain accurate ion quantification without the signal variation caused by secondary ion impacts.
2Productivity
If electrons from secondary positive ion collisions are detected, then more ions can be detected, but pulse height distribution broadens and quantification becomes inaccurate
Solution Approach 1:
The patent extracts electrons generated from secondary positive ion collisions before they can reach the electron detector. By removing these spurious electrons from the detection path, the system maintains narrow pulse height distributions and accurate quantification while still detecting all primary ions efficiently through the dynode-based electron generation mechanism.
Solution Approach 2:
The patent applies different quality requirements to different regions of the detector. The apertured electrode creates a selective environment where primary ions are allowed to generate useful electrons at the dynode, while secondary positive ions are blocked from generating harmful electrons downstream. This local differentiation of detection quality resolves the contradiction between detection efficiency and measurement precision.
3Measurement precision
If a detection threshold is applied to ions, then ion quantification can be performed, but low mass ions are lost due to signal variation
Solution Approach 1:
The patent removes the source of signal variation (secondary positive ion-generated electrons) from the detection system. This extraction stabilizes the pulse height distribution, ensuring that low mass ions produce detectable signals above the quantification threshold. As a result, the system maintains accurate ion quantification capability while recovering previously lost low mass ions, thereby increasing the total detected ion count.
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 improves the signal-to-noise ratio and narrows the pulse height distribution, enabling more accurate ion quantification across various ion masses by filtering out secondary electrons and maintaining a uniform electric potential.
Implementation Method 1
a dynode arranged and configured such that primary ions to be detected by the ion detector impact upon the dynode and generate first electrons
Implementation Method 2
an electron detector arranged and configured to attract and detect said first electrons
Data Source
AI summary
An ion detector for a mass and/or ion mobility spectrometer is disclosed. The ion detector comprises a dynode arranged and configured such that primary ions to be detected by the ion detector impact upon the dynode and generate first electrons and secondary positive ions, an electron detector arranged and configured to attract and detect said first electrons, and an apertured electrode. The apertured electrode comprises a plurality of apertures and is arranged and configured such that at least some of said secondary positive ions pass through the apertures of the electrode.