Sealed Electron Multiplier Barrier for Contamination Control
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Solution Overview
Problem
Electron multipliers in mass spectrometry suffer from reduced performance due to organic contamination, necessitating frequent recalibration and eventual replacement, which is inconvenient and inefficient.
Innovation Solution
Implementing an electron multiplier with a housing and an electron-transparent, gas-impermeable barrier that allows high-energy electrons to pass while blocking larger ions and organic molecules, maintaining a sealed environment to prevent contamination and extend the multiplier's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If electron multipliers are used to amplify secondary electrons in mass spectrometry, then signal amplification is achieved, but organic contamination accumulates on the dynode surface over time reducing performance
Solution Approach 1:
The system is divided into two separate environments: a vacuum environment for the electron multiplier and an atmospheric environment for the ion source. The electron multiplier is sealed in a housing that creates a physical barrier, preventing organic contaminants from reaching the dynode surfaces while allowing the device to function. This segmentation isolates the sensitive electron multiplier from harmful organic compounds.
Solution Approach 2:
An electron-transparent, gas-impermeable barrier (such as a thin metal foil or polymer film) serves as an intermediary between the ion source and the electron multiplier. This barrier allows electrons to pass through while blocking larger organic molecules and ions, thus protecting the dynode surfaces from contamination without interfering with the electron amplification process.
2Productivity
If electron multipliers operate continuously, then productivity is maintained, but the multiplier ages and requires recalibration or replacement
Solution Approach 1:
The electron multiplier is pre-sealed in a vacuum-tight housing before use, creating a protected environment in advance. This preliminary action of sealing the multiplier in vacuum prevents organic contamination from occurring during operation, thereby extending the multiplier's lifespan and reducing the frequency of recalibration or replacement.
Solution Approach 2:
The electron multiplier operates in a vacuum environment (inert atmosphere) created by sealing it in a housing. This vacuum environment prevents organic contaminants from depositing on the dynode surfaces, allowing the multiplier to maintain its performance characteristics over extended periods without aging or requiring frequent maintenance.
3Duration of action of stationary object
If the electron multiplier is sealed in vacuum to prevent contamination, then lifetime is extended, but electrons must pass through a barrier which may reduce transmission efficiency
Solution Approach 1:
A thin, electron-transparent film (such as aluminum foil, polymer film, or metalized film) is used as the barrier material. These thin films are sufficiently transparent to high-energy electrons while providing effective blocking of organic molecules and maintaining vacuum seal. The thin film design minimizes electron scattering and transmission losses while achieving the protective function.
Solution Approach 2:
The barrier may be constructed as a composite structure combining multiple materials (e.g., metal foil with polymer coating, or multiple thin layers) to optimize both electron transparency and gas impermeability. This composite approach allows the barrier to simultaneously transmit electrons efficiently while providing robust protection against organic contamination and maintaining vacuum integrity.
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 significantly extends the electron multiplier's lifetime by reducing organic contamination, minimizing the need for recalibration and replacement, and maintaining consistent performance.
Implementation Method 1
an electron-transparent, gas-impermeable barrier configured to allow electrons to pass through into the housing to reach a first discrete electron emissive surface
Implementation Method 2
an electron-transparent, gas-impermeable barrier configured to allow electrons to pass through into the housing
Implementation Method 3
Particles impact the surface which causes the surface to release multiple electrons. A conversion dynode arranged to generate secondary electrons
Implementation Method 4
Electron multipliers generally operate by way of secondary electron emission. Electrons released at one potential move to and impact a surface of a more positive potential causing the release of more electrons. As the electrons move from the entrance to the exit, the number of electrons can be dramatically increased
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An electron multiplier includes a series of discrete electron emissive surfaces or a continuous electron emissive resistive surface configured to provide an electron amplification chain; and a housing surrounding the series of electron emissive surfaces or the continuous electron emissive resistive surface and separating the environment inside the housing from the environment outside the housing. The housing includes an electron-transparent, gas-impermeable barrier configured to allow electrons to pass through into the housing to reach a first discrete electron emissive surface of the series of discrete electron emissive surfaces or a first portion of the continuous electron emissive resistive surface.