Thermionic Electron Emitter with Glassy Carbon Intermediary
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Solution Overview
Problem
The existing electron sources experience a decline in reliability due to hexaboride deposition in the vicinity of the heater, which hinders stable electricity flow and emitter performance over long-term operation.
Innovation Solution
An emitter design featuring first and second heaters with an intermediate member made of glassy carbon, having lower thermal conductivity than the electron source, is introduced. This intermediate member is positioned between the electron source and the heaters, allowing for higher heater temperatures and suppressing deposition by utilizing excess heat, while maintaining sufficient heat transmission and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater temperature is increased to improve electron emission, then electron source performance is improved, but hexaboride deposition occurs in the vicinity of the heater
Solution Approach 1:
An intermediate member made of glassy carbon is inserted between the heater and the electron source. This intermediary material has low thermal conductivity (100 W/m·K or less) compared to the electron source material, allowing it to block excessive heat from reaching the heater vicinity, thereby preventing hexaboride deposition while still permitting sufficient heat transmission to maintain electron emission performance.
2Object-generated harmful factors
If thermal conductivity of the intermediate member is decreased to suppress deposition, then deposition is reduced, but heat transmission to electron source decreases
Solution Approach 1:
The thermal conductivity parameter of the intermediate member is optimized to be 100 W/m·K or less, which is lower than the electron source material but not excessively low. This parameter change allows the intermediate member to sufficiently suppress heat conduction to prevent hexaboride deposition while maintaining adequate heat transmission to the electron source for sustained electron emission.
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 emitter maintains high reliability and stable performance over long periods by preventing hexaboride deposition near the heaters, ensuring efficient heating and reducing electrical resistance.
Implementation Method 1
first and second heaters for generating heat by energization
Implementation Method 2
an electron source comprising a first material emitting an electron by being heated by the first and second heaters
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
An emitter according to the present disclosure includes: first and second heaters generating heat by energization; an electron source comprising a first material emitting an electron by being heated by the first and second heaters; and an intermediate member interposed between the electron source, and the first and second heaters, the intermediate member comprising a second material lower in thermal conductivity than the first material.