Gas-Sealed Electron Detector Structure for Low Ion Feedback
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Solution Overview
Problem
The performance of electron emission-based detectors in mass spectrometry degrades over time due to secondary electron emission reduction, leading to decreased gain and shortened service life, and internal ion feedback causes 'false' pulses and potential permanent discharge, limiting the operational life and accuracy of detectors like microchannel plate detectors.
Innovation Solution
A detector design that inhibits or prevents the flow of gas from the external environment into the internal detector environment using sealants and non-linear or tortuous paths between detector elements, creating a gas-tight seal and reducing vacuum conductance to protect electron emissive surfaces from contaminants and improve detector performance and longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the detector operates continuously in a mass spectrometer, then detection capability is maintained, but performance degrades over time due to secondary electron emission reduction and contamination
Solution Approach 1:
The detector is divided into separate detector elements that can be individually replaced or maintained. This segmentation allows the internal environment to be protected and maintained separately from the external environment, extending the service life of the electron emissive surfaces while maintaining detection capability.
Solution Approach 2:
The patent creates a protected internal environment within the detector that isolates the electron emissive surfaces from contaminants in the external environment. This inert environment protection reduces contamination and secondary electron emission reduction, thereby extending service life and maintaining performance stability.
2Ease of operation
If gas flow is allowed between external and internal environments, then detector accessibility is improved, but contamination of electron emissive surfaces increases
Solution Approach 1:
The harmful gas flow between external and internal environments is extracted or removed by implementing gas-tight seals. This separates the beneficial accessibility from the harmful contamination, allowing the detector to remain accessible while protecting the internal electron emissive surfaces from external contaminants.
Solution Approach 2:
A protected internal environment is created that prevents contaminant ingress while maintaining detector functionality. The gas-tight sealing creates an inert barrier that blocks harmful gas flow paths without compromising detector accessibility or operation.
3Measurement precision
If internal ion feedback is permitted, then detection sensitivity is maintained, but false pulses and permanent discharge increase
Solution Approach 1:
The patent addresses ion feedback by modifying the detector construction to prevent ion-induced secondary emission. By creating gas-tight seals and protected environments, the harmful ion feedback that causes false pulses is eliminated, thereby improving signal accuracy while maintaining detection sensitivity through proper electron collection.
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
The solution extends the service life and improves performance by reducing contamination and noise, increasing sensitivity and dynamic range, and minimizing ion feedback, while maintaining a cleaner internal environment for the electron multiplier, thus enhancing the detector's operational stability and accuracy.
Implementation Method 1
the one or more detector elements are configured to inhibit or prevent flow of a gas from the environment external the detector to the environment internal the detector
Implementation Method 2
the impact of a single or multiple particles on the multiplier impact surface causes single or (preferably) multiple electrons associated with atoms of the impact surface to be released
Implementation Method 3
Each dynode is capable of emitting one or more electrons upon impact from secondary electrons emitted from previous dynodes, thereby amplifying the input signal
Implementation Method 4
the resistive material of the continuous dynode itself is used as a voltage divider to distribute voltage along the length of the emissive surface
Data Source
AI summary
A detector includes: one or more electron emissive surfaces; first and second housing elements defining a space therebetween; and a deformable member or a deformable mass some or all of which occupies the space. The first and second housing elements and the deformable member or the deformable mass define on one side an environment internal the detector and on another side an environment external the detector. The deformable member or the deformable mass has a central region which when contacted by the first and/or second housing elements is deformed so as to inhibit or prevent passage of a gas through the space.