Microwave Source Cathode Heater Layout for Stable Electron Emission
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Solution Overview
Problem
Existing microwave sources in radiotherapy devices face challenges in efficiency and stability, leading to reduced service life and increased energy consumption.
Innovation Solution
The microwave source incorporates a cathode heater with a double helix filament configuration and a thermionic emitter, where the filaments' current flows are oppositely directed to counterbalance magnetic forces, and an electron emission layer with grooves to accommodate thermal expansion, enhancing stability and reducing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional cathode heater design is used, then the structure is simple, but the heat transfer efficiency is low and energy consumption is high
Solution Approach 1:
The cathode heater is segmented into multiple filaments (first filament, second filament, third filament) arranged in a specific geometric configuration. This segmentation allows each filament to contribute to heating different regions of the cathode, improving overall heat transfer efficiency while distributing the energy load across multiple elements rather than relying on a single high-power element.
Solution Approach 2:
The filaments are arranged in a curved or spherical geometric configuration around the cathode. This curved arrangement optimizes the thermal radiation pattern and ensures more uniform heat distribution across the cathode surface, improving heat transfer efficiency without requiring excessive energy input from any single filament.
2Reliability
If the thermionic emitter is heated to high temperature, then electron emission is improved, but thermal expansion causes deformation and reduces stability
Solution Approach 1:
The patent explicitly accounts for thermal expansion by designing the thermionic emitter with expansion compensation features. The emitter structure includes elements that can accommodate or compensate for thermal expansion when heated to high temperatures, preventing deformation and maintaining structural stability. This allows the emitter to reach the high temperatures needed for efficient electron emission without suffering from thermal distortion.
3Temperature
If the filament current is increased to improve heating, then heat transfer efficiency improves, but magnetic forces cause filament deformation
Solution Approach 1:
The patent employs a configuration where multiple filaments carry currents in opposite directions, creating opposing magnetic forces that counterbalance each other. This counterbalancing effect neutralizes the magnetic forces that would otherwise cause filament deformation, allowing the filaments to operate at high temperatures without shape distortion.
Solution Approach 2:
The filaments are arranged in an asymmetric configuration with different spatial orientations and current directions. This asymmetric arrangement is deliberately designed to create magnetic force distributions that self-compensate, where the magnetic forces on individual filaments are balanced by forces on other filaments in the asymmetric structure.
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 design improves heat transfer efficiency, reduces energy consumption, and prolongs the service life of the microwave source, thereby stabilizing the radiotherapy device's operation.
Implementation Method 1
The cathode heater may include a first component, and a second component enclosing at least a portion of the first component. The thermionic emitter may be configured to release electrons when the thermionic emitter is heated by the cathode heater.
Implementation Method 2
The thermionic emitter may be configured to release electrons when the thermionic emitter is heated by the cathode heater.
Implementation Method 3
When the first filament and the second filament are disposed in a magnetic field and powered by a power source, a first direction of a first current flow in the first filament may be opposite to a second direction of a second current flow in the second filament such that a first force on the first filament due to the magnetic field is in line with and in an opposite direction to a second force on the second filament due to the magnetic field.
Data Source
AI summary
The present disclosure is related to a microwave source. The microwave source may include a cathode heater and a thermionic emitter. The cathode heater may include a first component, and a second component enclosing at least a portion of the first component. The thermionic emitter may be configured to release electrons when the thermionic emitter is heated by the cathode heater. At least a portion of the second component of the cathode heater may be in contact with the thermionic emitter.