External Dielectric Barrier Discharge VUV Photon Source
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Solution Overview
Problem
Current ultraviolet photo-ionization sources are limited by low photon flux and unwanted ion chemistry in high-pressure environments, making them inefficient for both low-pressure and high-pressure applications in mass spectrometry systems.
Innovation Solution
A vacuum ultraviolet (VUV) photon source is developed using a dielectric barrier discharge (DBD) mechanism, where a periodic voltage is applied between electrodes separated by a dielectric barrier, generating excimers that emit VUV photons, which are then transmitted through a VUV window to ionize samples in a chamber, allowing for efficient ionization in various pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a low internal-pressure gas discharge lamp is used in an atmospheric pressure ionization chamber, then ionization can be achieved, but the photon flux is low and ambient optical absorption reduces the UV flux intensity
Solution Approach 1:
The patent inverts the conventional approach by placing electrodes outside the ionization chamber rather than inside. This external electrode configuration allows VUV photons to be generated outside the chamber and transmitted through a window, eliminating ambient optical absorption while maintaining effective ionization. The dielectric barrier discharge mechanism generates intense VUV radiation externally, which then passes through the chamber window without being absorbed by the atmospheric pressure environment.
Solution Approach 2:
The patent introduces a VUV-transmitting window as an intermediary component that separates the photon generation zone from the ionization chamber. This window allows VUV photons to pass from the external discharge region into the chamber while blocking external environmental interference. The window acts as a mediator that enables energy transfer without direct contact between the high-voltage discharge system and the sample environment.
2Productivity
If atmospheric pressure ionization is used, then ionization of samples can occur, but unwanted ion chemistry occurs and ionization efficiency is reduced
Solution Approach 1:
The patent segments the ionization process into two distinct zones: a VUV photon generation zone outside the chamber and a sample ionization zone inside the chamber. By separating photon generation from sample interaction, the system eliminates unwanted ion chemistry that would occur in conventional atmospheric pressure sources where photons are generated within the same chamber as the sample. The dielectric barrier discharge generates photons externally, which then selectively ionize only the intended analyte molecules through the window.
Solution Approach 2:
The patent creates an inert environment for photon generation by using a controlled gas discharge outside the chamber, isolated from the sample matrix. The dielectric barrier discharge operates in a controlled atmosphere that prevents unwanted chemical reactions, while still allowing the generated VUV photons to effectively ionize the sample through the window. This inert external environment eliminates interference from chamber wall interactions and ambient contaminants.
3Illumination intensity
If external electrodes with dielectric barrier are used to generate VUV photons, then high photon flux is achieved, but the device complexity increases
Solution Approach 1:
The patent implements a universal design where the external dielectric barrier discharge assembly serves multiple functions: it generates intense VUV photons, isolates the high-voltage system from the sample chamber, and provides a sealed interface through the window. This multi-functional external configuration eliminates the need for internal electrode structures, vacuum sealing complexities, and internal high-voltage insulation, thereby reducing overall device complexity while maintaining high photon flux output.
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 VUV photon source achieves higher photon flux and improved ionization efficiency with minimal ionization of non-analytical molecules, enabling effective photo-ionization in both low-pressure and high-pressure environments, enhancing the sensitivity and dynamic range of mass spectrometry systems.
Implementation Method 1
generating a dielectric barrier discharge (DBD) in an interior of a photon source by applying a periodic voltage between a first electrode and a second electrode
Implementation Method 2
the DBD produces excimers from a gas in the gap; and transmitting VUV photons emitted from the excimers
Implementation Method 3
VUV photons, which are then transmitted through a VUV window to ionize samples in a chamber
Data Source
AI summary
A vacuum ultraviolet (VUV) photon source includes a body, a VUV window, electrodes disposed on the body outside an interior thereof, and a dielectric barrier between the electrodes. A method for generating VUV photons includes generating a dielectric barrier discharge (DBD) in an interior of a photon source by applying a periodic voltage between a first electrode and a second electrode separated by a dielectric barrier, wherein the DBD produces excimers from a gas in a gap between the electrodes, and transmitting VUV photons through a window of the photon source.