Convex Cathode Electron Beam Device
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Solution Overview
Problem
Existing cathode designs struggle to achieve high surface field strengths necessary for producing electron beams with high beam density, particularly with cold cathodes, due to low electric field strengths.
Innovation Solution
A cathode component with a convex cathode face and a concentric extraction electrode, aligned slightly inclined to a strong homogeneous magnetic field, suppresses disruptive discharges and allows for high electric field strengths, enabling high emission current densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a concave cathode face is used, then the cathode structure is simple, but the electric field strength at the cathode surface is low
Solution Approach 1:
The patent applies curvature by using a convex cathode face instead of a concave or flat one. The convex shape with a specific radius of curvature concentrates the electric field lines at the cathode surface, thereby increasing the electric field strength and enabling high current density emission without requiring complex structural modifications.
2Strength
If a convex cathode face is used to increase electric field strength, then high emission current density is achieved, but disruptive discharge to the extraction electrode occurs
Solution Approach 1:
The patent changes the magnetic field parameter by introducing a strong homogeneous magnetic field that is slightly inclined relative to the cathode surface. This magnetic field parameter modification suppresses disruptive discharge by confining electron motion and preventing direct discharge paths to the extraction electrode, while maintaining high emission current density.
Solution Approach 2:
The magnetic field acts as an intermediary between the convex cathode face and the extraction electrode. It mediates the interaction by controlling electron trajectories, preventing direct discharge while allowing controlled electron emission, thus resolving the contradiction between high field strength and discharge suppression.
3Productivity
If a convex cathode face with slight inclination to magnetic field lines is used, then high-density electron beams are produced, but the alignment precision requirement increases
Solution Approach 1:
The patent optimizes the inclination angle parameter between the cathode surface and magnetic field lines. By selecting a specific small angle, the system achieves high electron beam density while keeping alignment precision requirements within practical manufacturing tolerances. This parameter optimization balances performance with manufacturability.
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 allows for the production of high-density electron beams while reducing space charge effects and preventing disruptive discharges, resulting in efficient electron beam extraction.
Implementation Method 1
a magnetic field extending almost collinearly to the convex cathode face is arranged to cause the extraction of the electron beam
Implementation Method 2
the alignment of the convex cathode face is selected in such a way that the alignment is slightly inclined in relation to the field lines of a strong homogeneous magnetic field
Implementation Method 3
A cathode component with a cathode face used to extract the electron beam
Data Source
AI summary
A device for the production of an electron beam with high surface strengths. The device has a cathode component with a convex cathode face with a predetermined radius for extracting the electron beam in such an alignment that a magnetic field or the magnetic field lines thereof, for causing the extraction of the electron beam, is almost collinearly to the convex cathode face.