Electron Gun Cathode With Through Hole for Heat Diffusion
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Solution Overview
Problem
Conventional electron guns suffer from premature degradation due to back bombardment of electrons and ions, which causes overheating and damage to the heater and insulating materials, leading to a short operational life.
Innovation Solution
An electron gun design featuring a cathode with a central through hole and a heat-resistant member that diffuses heat generated by back-bombarded electrons and ions, preventing local heating and extending the lifespan of the heater and insulating materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional electron gun structure is used, then electrons can be emitted and focused, but back-bombarded electrons and ions cause local overheating and damage to the heater and insulating materials, reducing operational life
Solution Approach 1:
A heat-resistant member is introduced as an intermediary component positioned between the cathode and the heater/insulating materials. This member intercepts back-bombarded electrons and ions, converting their kinetic energy into heat in a location that can withstand high temperatures, thereby protecting the heater and insulating materials from thermal damage and extending operational life.
Solution Approach 2:
The harmful kinetic energy of back-bombarded electrons and ions is converted into beneficial heat at a location where it can be tolerated. The heat-resistant member transforms the damaging effect into localized heating that does not compromise the overall system reliability, as the heat is contained in a region designed to withstand it.
2Reliability
If a through hole is provided in the cathode, then back-bombarded particles can pass through to a heat-resistant member, but the heater arrangement becomes more complex
Solution Approach 1:
The cathode is segmented by introducing a through hole, dividing it into regions that serve different functions. This segmentation allows back-bombarded particles to pass through to the heat-resistant member while maintaining the heating function in other regions, thus protecting the heater and insulating materials without compromising the overall heating capability.
3Temperature
If the cathode central portion is made open, then heat diffusion is improved, but the insulating material cannot be positioned effectively
Solution Approach 1:
The heat-resistant member serves as an intermediary that enables both heat diffusion and effective positioning of insulating materials. By placing this member in the through hole, heat from back bombardment can be diffused laterally, while the insulating materials can be positioned around or near this member without being directly exposed to the full impact of back-bombarded particles.
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 design effectively suppresses local shock and heat generation at the cathode surface, preventing damage and extending the operational life of the electron gun by diffusing heat generated by back-bombarded electrons and ions to other portions, thus ensuring stable thermionic emission for a longer duration.
Implementation Method 1
an electron gun to emit thermions by using a heater to heat a cathode in which a thermionic emission substance is splayed onto, coated onto, or impregnated into a metal base body
Implementation Method 2
a heat resistant member having a first portion to close the through hole and a second portion being positioned between the cathode and the heater... heat generation due to back bombardment of the electrons or ions is diffused by the heat resistant member to portions other than the cathode surface
Data Source
AI summary
An electron gun comprising a cathode having an electron emitting surface and whose planar shape is circular; a heater; an anode being arranged to oppose the cathode; and a heat resistant member. The anode applies a positive potential relative to the cathode to extract electrons in a predetermined direction. The cathode has, in a central portion thereof, a through hole along a central axis of the cathode. The heat resistant member has a first portion to close the through hole and a second portion being positioned between the cathode and the heater.