Electron Gun Cathode Through-Hole for Back-Streaming Electron Heat
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Solution Overview
Problem
Back-streaming electrons in electron guns can cause overheating of the cathode, reducing its lifetime and performance.
Innovation Solution
An electron gun design featuring a hollow cathode with a through hole to allow back-streaming electrons to pass through, combined with a grid structure positioned corresponding to the through hole to facilitate electron focusing and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid cathode is used to emit electrons, then electron emission is effective, but back-streaming electrons cause overheating and reduce cathode lifetime
Solution Approach 1:
The cathode is designed as a hollow structure with a through-hole, segmenting the solid cathode into a hollow cavity and an opening. This segmentation allows back-streaming electrons to pass through the through-hole instead of being absorbed by the cathode, thereby reducing overheating and extending cathode lifetime while maintaining electron emission effectiveness.
2Temperature
If a through-hole is added to the cathode to allow back-streaming electrons to pass through, then cathode overheating is reduced, but electron beam focusing may be affected
Solution Approach 1:
A grid structure is introduced as an intermediary component positioned between the cathode and the anode. The grid structure includes multiple meshes that can be adjusted to control electron beam focusing while allowing back-streaming electrons to pass through. This intermediary structure resolves the conflict by providing both beam focusing capability and passage for back-streaming electrons.
Solution Approach 2:
The grid structure is designed to be adjustable along the common axis between the cathode and the anode. By dynamically adjusting the position of the grid structure, the electron beam focusing can be optimized while maintaining the through-hole's function of allowing back-streaming electrons to pass through. This dynamic adjustment capability resolves the focusing issue without compromising the temperature reduction benefit.
3Manufacturing precision
If a grid structure is added to improve electron focusing, then electron beam convergence is improved, but device complexity increases
Solution Approach 1:
The grid structure serves multiple functions simultaneously: it acts as a focusing element for the electron beam, provides structural support for the through-hole, and allows back-streaming electrons to pass through its meshes. By combining multiple functions into a single component, the device complexity is minimized while achieving improved electron beam focusing.
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 reduces or eliminates overheating of the cathode by allowing back-streaming electrons to pass through, thereby extending the cathode's lifetime and improving electron beam convergence.
Implementation Method 1
a cathode with an emitting surface configured to emit electrons
Implementation Method 2
an anode configured to attract the emitted electrons from the cathode to the anode and focus the emitted electrons into an electron beam
Implementation Method 3
a grid structure configured to facilitate the focusing of the emitted electrons
Data Source
AI summary
An electron gun may include a cathode with an emitting surface configured to emit electrons. The cathode may include a through hole that goes through the emitting surface and is configured to allow back-streaming electrons of the emitted electrons to pass through. The electron gun may also include an anode configured to attract the emitted electrons from the cathode to the anode and focus the emitted electrons into an electron beam. The electron gun may also include a grid structure configured to facilitate the focusing of the emitted electrons, the grid structure being positioned corresponding to the through hole.