Mass Spectrometer Total Pressure Measurement via VUV Light Detection
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Solution Overview
Problem
Existing mass spectrometry techniques face challenges in precisely measuring total pressure at higher pressures due to ion collisions in the quadrupole, leading to reduced ion detection efficiency and linearity issues, and require complex structures or excessive vacuum ultraviolet light, which increases costs and noise.
Innovation Solution
A mass spectrometer configuration including an ionizer, a filter, an ion detector, a light detector for vacuum ultraviolet light, and an arithmetic unit to calculate partial pressure using both ion and light detection values, allowing for precise total pressure measurement without passing ions through the quadrupole and minimizing vacuum ultraviolet light noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ions are measured without passing through a mass analyzer to determine total pressure, then total pressure measurement is simplified, but the ion source structure becomes complicated and cost increases
Solution Approach 1:
The patent introduces a light detector as an intermediary device that detects vacuum ultraviolet light generated during ionization as a mediator signal to infer total pressure, avoiding the need for complex ion source modifications while maintaining measurement accuracy
Solution Approach 2:
The patent replaces the mechanical/ion-based pressure measurement approach with an optical detection method, using vacuum ultraviolet light detection instead of ion current measurement to determine total pressure, thereby simplifying the ion source structure
2Measurement precision
If vacuum ultraviolet light is used to calculate total pressure by irradiating an ion detector, then pressure measurement is enabled, but the vacuum ultraviolet light appears as noise during mass spectrometry
Solution Approach 1:
The patent segments the detection functions by introducing a separate light detector specifically for vacuum ultraviolet light, distinct from the ion detector used for mass spectrometry, allowing simultaneous operation without interference
Solution Approach 2:
The patent uses vacuum ultraviolet light as a mediator signal for pressure measurement while employing a dedicated light detector to capture this signal before it can interfere with the ion detection process
3Productivity
If ions pass through a quadrupole at higher pressures, then mass spectrometry can be performed, but ion collisions with gas molecules disturb trajectories and reduce detection efficiency
Solution Approach 1:
The patent employs vacuum ultraviolet light as a mediator to measure total pressure independently of ion transmission through the quadrupole, providing accurate pressure data even when ion detection efficiency varies due to collisions
Solution Approach 2:
The patent changes the measurement parameter from ion current (affected by collisions) to vacuum ultraviolet light intensity (unaffected by collisions), enabling accurate total pressure measurement across a wider pressure range
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 enables high-precision total pressure measurement and mass spectrometry with a simple structure, reducing maintenance and production costs while maintaining precision even at higher pressures.
Implementation Method 1
an ionizer configured to ionize a measurement gas
Implementation Method 2
a light detector configured to detect a light detection value based on vacuum ultraviolet light generated when the ionizer ionizes the measurement gas
Implementation Method 3
a filter configured to selectively pass therethrough an ion of a target gas having a predetermined mass-to-charge ratio among components of the measurement gas ionized by the ionizer
Implementation Method 4
an ion detector configured to detect an ion detection value based on the ion of the target gas that passes through the filter
Data Source
AI summary
An object of the present invention is to provide a mass spectrometer having a simple structure and being capable of precisely measuring a total pressure and performing mass spectrometry with high precision. A mass spectrometer according to one embodiment includes a quadrupole configured to selectively pass therethrough an ion of a target gas having a predetermined mass-to-charge ratio among components of a measurement gas ionized by an ion source, an ion detector configured to detect an ion current value based on the ion of the target gas that passes through the quadrupole, a total pressure measurer configured to detect a photoelectric current value based on vacuum ultraviolet light generated when the ion source ionizes the measurement gas, and an arithmetic unit configured to calculate a partial pressure of the target gas by using the photoelectric current value and the ion current value.