Electron Emission Ion Source for Dual Positive-Negative Ionization
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Solution Overview
Problem
Existing ion generation apparatuses require additional components to generate both positive and negative ions, leading to increased size and complexity when used in analysis applications like ion mobility spectrometry, as they rely on separate mechanisms for each ion type.
Innovation Solution
An ion generation apparatus incorporating an electron emission device with a lower electrode, a surface electrode, and an intermediate layer, along with a controller to apply voltages that enable the generation of positive ions by ensuring electrons emitted have sufficient energy to ionize gas components, and switching between positive and negative ion modes by adjusting electrode potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an electron emission device is used as an ion source for analysis apparatus requiring both negative and positive ionization, then negative ions can be generated through electron attachment, but additional ion sources (radiation source, corona discharge, or UV light source) must be combined to generate positive ions, which increases the size of the apparatus
Solution Approach 1:
The electron emission device is designed to perform multiple functions: it can generate both negative ions through electron attachment and positive ions through controlled electron emission with sufficient energy. By adjusting the voltage applied to the electron emission device, the same component serves dual ionization purposes, eliminating the need for separate ion sources and reducing overall apparatus size.
Solution Approach 2:
The invention changes the operational parameters of the electron emission device by applying different voltages. When a voltage corresponding to energy higher than the ionization energy of the target gas is applied, the device generates positive ions through ionization. When lower voltages are applied, electrons attach to form negative ions. This parameter adjustment allows one device to replace multiple ionization mechanisms.
2Adaptability or versatility
If a high voltage is applied between a needle electrode and a flat-plate electrode to generate corona discharge for positive ion generation, then positive ions can be produced, but the device complexity increases when combining this with an electron emission device for negative ion generation
Solution Approach 1:
The invention merges the positive ion generation function into the electron emission device itself. The electron emission device structure incorporates elements that enable both electron attachment (for negative ions) and controlled electron emission with ionization capability (for positive ions). This consolidation eliminates the need for a separate corona discharge apparatus, reducing structural complexity while maintaining dual ion generation capability.
3Adaptability or versatility
If electrons are emitted from the electron emission device to attach to target substances for negative ionization, then negative ions are generated, but the electrons may lack sufficient energy to ionize gas components for positive ion generation
Solution Approach 1:
The invention introduces dynamic control of the electron emission device through variable voltage application. The system can switch between different operational states: low voltage for electron attachment (negative ion generation) and high voltage corresponding to ionization energy for electron emission that creates positive ions. This dynamic parameter adjustment enables the same electron emission device to adapt its energy output to different ionization requirements.
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
Enables the generation of both positive and negative ions using a single apparatus, reducing size and complexity while maintaining analysis accuracy through controlled voltage switching, allowing for qualitative and quantitative analysis in both ion modes.
Implementation Method 1
the electrons flow from the lower electrode to the surface electrode, and the electrons are emitted from the surface electrode
Implementation Method 2
the electrons emitted from the surface electrode may have an energy higher than the ionization energy of a first gas component, and the first gas component near the surface electrode may be positively ionized
Implementation Method 3
As the controller applies a voltage to the surface electrode or the opposite electrode such that the potential of the surface electrode becomes higher than the potential of the opposite electrode, the positive ions generated near the surface electrode may travel toward the opposite electrode
Implementation Method 4
The ion generation apparatus applies a high voltage between a needle electrode and a flat-plate electrode to generate corona discharge in order to generate positive ions
Data Source
AI summary
An ion generation apparatus according to the present invention includes an electron emission device, an opposite electrode, and a controller, the electron emission device includes a lower electrode, a surface electrode, and an intermediate layer provided between the lower electrode and the surface electrode, the opposite electrode is provided to be opposite to the surface electrode, and the controller is provided to apply a voltage to the surface electrode, the lower electrode, or the opposite electrode such that a potential of the surface electrode becomes higher than a potential of the lower electrode and a potential of the opposite electrode in a positive ion mode.