Heat-Blocking Plate for Mass Spectrometer Ion Source
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Solution Overview
Problem
The existing mass spectrometer ion sources face issues with radiation heat from the filament causing local heating and temperature distribution irregularities in the ionization chamber, leading to decomposition of metallic materials and reduced ion detection efficiency due to disturbances in the electric field.
Innovation Solution
A heat-blocking plate member made of an electrically conductive material is placed between the filament and the ionization chamber to shield against radiation heat and maintain a uniform temperature, while being thermally connected to the heating unit to control the temperature and set at the same potential as the ionization chamber to minimize electric field interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a filament is used to generate thermions for ionization, then ion production is achieved, but radiation heat from the filament causes local heating and temperature distribution irregularities in the ionization chamber
Solution Approach 1:
A heat-blocking plate is introduced as an intermediary component between the filament and the ionization chamber. This plate blocks radiation heat from directly heating the ionization chamber wall, preventing local heating and temperature distribution irregularities while allowing the filament to continue generating thermions for ionization.
2Power
If the ionization chamber wall is heated to high temperature, then thermion generation is enhanced, but the metallic material becomes activated and produces decomposition products that create noise
Solution Approach 1:
The heat-blocking plate serves as a protective intermediary that prevents excessive heat from reaching the ionization chamber wall. This avoids the activation and decomposition of metallic materials in the wall, eliminating the source of noise from decomposition products while maintaining sufficient thermion generation through controlled heating.
3Productivity
If a potential difference is applied to the filament for thermion acceleration, then ionization efficiency is improved, but the external electric field penetrates into the ionization chamber and disturbs the internal electric field, reducing ion extraction efficiency
Solution Approach 1:
The heat-blocking plate acts as an electric field barrier, serving as an intermediary that prevents the external accelerating electric field from penetrating into the ionization chamber. This maintains the integrity of the internal electric field required for efficient ion extraction, while still allowing the filament to generate and accelerate thermions effectively.
4Device complexity
If no heat-blocking measure is taken, then the structure is simple, but the ionization chamber experiences local heating and temperature abnormalities
Solution Approach 1:
A heat-blocking plate is positioned between the filament and the ionization chamber to serve as a thermal intermediary. This simple structural addition effectively blocks radiation heat from causing local heating and temperature distribution irregularities in the ionization chamber, maintaining temperature uniformity with minimal structural complexity.
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 prevents heat decomposition, maintains uniform temperature, and enhances ion extraction efficiency by reducing noise and electric field disturbances, resulting in improved ion detection sensitivity and production efficiency.
Implementation Method 1
an ion source having a filament for generating thermions by being heated
Implementation Method 2
the influence of the radiation heat from the filament can be alleviated
Data Source
AI summary
An electrically conductive heat-blocking plate 11 with an opening 12 for allowing thermions to pass through is provided between a filament 3, whose temperature can be as high as 2000° to 3000° C., and an ionization chamber 2. The heat-blocking plate 11 is thermally connected via an aluminum block 10 to a heater for maintaining the ionization chamber 2 within a range temperature from 200° to 300° C., and also electrically set at a ground potential, which is approximately equal to the potential of the ionization chamber 2. The heat-blocking plate 11 blocks the radiation heat that the filament 3 emits when energized. Thus, the wall of the ionization chamber 2 is prevented from being locally heated to an abnormally high temperature. As a result, the inner space of the ionization chamber 2 is maintained at an approximately uniform temperature, and the noise due to the decomposition of a metallic material by abnormal heating is prevented. The heat-blocking plate 11 also prevents a thermion-accelerating electric field from penetrating through an electron injection port 5 into the ionization chamber 2 and impeding the extraction of ions produced within the ionization chamber 2. Thus, the ion extraction efficiency is also improved.