Two-Part Vacuum Feedthrough Anode for X-Ray Tube Stress Relief
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Solution Overview
Problem
Existing high voltage vacuum feedthroughs for X-ray tubes face challenges with mechanical stress and leakage due to thermal expansion differences between copper anodes and ceramic insulators, leading to complex production processes and limited flexibility in target material changes.
Innovation Solution
Designing the anode in two parts, with a rear part made from a metallic material matching the ceramic's thermal expansion coefficient for vacuum-tight soldering, and a front part with higher thermal conductivity for efficient heat dissipation, allowing for easy assembly and flexibility in target materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a copper anode is soldered into a ceramic insulating body, then a vacuum-tight connection is achieved, but large mechanical stress is generated due to different thermal expansion coefficients causing leakage
Solution Approach 1:
The anode is divided into two separate parts: a copper front part for heat dissipation and a rear part made of material matching the ceramic's thermal expansion coefficient for stress-free connection. This segmentation allows each part to fulfill its specific function without compromising the other, resolving the contradiction between vacuum-tightness and mechanical stress resistance.
Solution Approach 2:
The rear part of the anode acts as an intermediary component between the copper front part and the ceramic insulating body. It has one surface that matches the ceramic's thermal expansion coefficient for stress-free soldering, while the other surface connects to the copper anode, thus mediating the thermal expansion mismatch and preventing leakage.
2Reliability
If elastic claws are formed on the anode to absorb mechanical stress, then vacuum-tightness is maintained, but the production process becomes very complex
Solution Approach 1:
Instead of modifying the anode with complex elastic claws, the invention segments the anode into two parts with different material properties. The rear part is designed with material matching the ceramic's thermal expansion coefficient, providing stress absorption through material selection rather than geometric complexity, thus simplifying production.
3Strength
If a hollow-cylindrical section is used at the anode end, then mechanical stress is reduced, but the anode is only suited for small heat flows and may deform during installation
Solution Approach 1:
The anode is segmented into a front copper part with high thermal conductivity for efficient heat dissipation and a rear part for mechanical stress management. This allows the system to handle high power applications while maintaining mechanical integrity, overcoming the limitations of hollow-cylindrical designs.
Solution Approach 2:
Different parts of the anode are assigned different material qualities: the front part uses copper for high thermal conductivity to handle heat flow, while the rear part uses material matching the ceramic's thermal expansion coefficient for mechanical stress resistance. This local differentiation of material properties resolves the contradiction between power capacity and mechanical strength.
4Power
If the anode is designed in two parts with different materials, then heat dissipation is improved and target material changes are enabled, but the assembly process becomes more complex
Solution Approach 1:
The anode is segmented into two parts that can be manufactured separately and assembled. The rear part with material matching the ceramic can be soldered first to ensure vacuum-tightness, followed by attachment of the copper front part. This segmentation enables target material changes in the front part without affecting the soldered connection, and the standardized rear part simplifies the overall assembly process.
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 solution ensures reliable vacuum-tightness and efficient heat dissipation, simplifying production and enabling quick adaptation to different target materials without compromising the solder joint integrity.
Implementation Method 1
the thermal expansion coefficient αht of which corresponds to the thermal expansion coefficient αker of the ceramic material
Implementation Method 2
the heat conductivity λvt of which is larger than the heat conductivity λht of the first metallic material of the rear part
Implementation Method 3
the rear part is arranged in the hollow space of the insulating body and is soldered into the insulating body in a vacuum-tight fashion
Data Source
AI summary
A high voltage vacuum feed through (23) for an electron tube (25) has an anode (28) and an insulating body (1) of ceramic material, the insulating body (1) having a continuous hollow space (10). The anode (28) has a rear part (2) and a front part (3) mounted thereto. The rear part (2) consists of a first metallic material, having a thermal expansion coefficient corresponding to a thermal expansion coefficient of the ceramic material. The rear part (2) is arranged in the hollow space (10) of the insulating body (1) and is soldered into the insulating body (1) in a vacuum-tight fashion. The front part (3) has a second metallic material whose heat conductivity is larger than that of the first metallic material. The high voltage vacuum feed through reliably remains vacuum-tight during operation and can be easily provided with different target materials.