X-ray Generator Irradiation Window Thermal Anisotropy
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Solution Overview
Problem
X-ray generators face challenges in managing heat generated at the irradiation window, leading to increased temperature, which can cause gas release, thermal stress on vacuum seals, and reduced X-ray effectiveness due to cooling requirements and structural limitations in both transmission and reflection types.
Innovation Solution
Implementing an irradiation window with thermal anisotropy, where thermal conductivity differs between the direction it spreads and its thickness, using materials like thermally anisotropic graphite or multilayer structures with varying thermal conductivities to direct heat flow selectively, thereby reducing heat transfer to specific areas or sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the irradiation window is made thicker to increase thermal capacity, then the temperature increase is reduced, but the X-ray absorption increases and the distance to the object must be increased, reducing magnification capability
Solution Approach 1:
The patent changes the thermal conductivity parameter of the irradiation window material from isotropic to anisotropic. By selecting a material where thermal conductivity in the thickness direction is lower than in the spreading direction, heat is conducted away laterally rather than thickness-wise, maintaining low temperature without requiring increased thickness that would absorb X-rays.
Solution Approach 2:
The patent employs composite material structures combining materials with different thermal conductivity characteristics. The irradiation window uses a composite approach where the material composition and structure are designed to achieve directional thermal conductivity properties, allowing heat management without compromising X-ray transmission.
2Temperature
If water cooling or air cooling is applied to the irradiation window, then the temperature increase is suppressed, but the device complexity and space requirements increase
Solution Approach 1:
The irradiation window performs self-cooling through its inherent anisotropic thermal conductivity properties. The material structure itself directs heat flow laterally without requiring external cooling systems, making the window serve its own thermal management needs and eliminating additional cooling apparatus.
Solution Approach 2:
By changing the thermal conductivity parameters of the window material to be anisotropic, the system achieves passive thermal management. The material parameters are selected such that heat naturally conducts along the spreading direction rather than through the thickness, eliminating the need for active cooling mechanisms.
3Temperature
If a shield member is provided to prevent electron beam collision with the irradiation window, then heat generation at the window is reduced, but the device complexity and internal space requirements increase
Solution Approach 1:
The irradiation window material itself provides the protective function against electron beam heating through its anisotropic thermal properties. Rather than requiring a separate shield member to protect the window, the window material's directional heat conduction inherently protects it from thermal damage, making the system self-protecting.
4Temperature
If the thermal conductivity in the thickness direction is made higher, then heat is conducted away from the irradiation point, but heat affects objects closer to the window and magnification capability is reduced
Solution Approach 1:
The patent inverts the conventional thermal conductivity parameter relationship. Instead of making thickness-direction conductivity higher, it makes the spreading-direction conductivity higher than the thickness-direction conductivity. This parameter inversion directs heat laterally away from the irradiation point while preventing heat from reaching objects on the X-ray side, solving both temperature management and object protection simultaneously.
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 approach allows for controlled heat dissipation, reducing thermal stress on vacuum seals and maintaining X-ray effectiveness by directing heat flow according to the X-ray tube's purpose, without the need for additional cooling members, resulting in a compact and efficient design.
Implementation Method 1
the irradiation window has thermal anisotropy, and therefore, the direction in which the heat from the irradiation window mainly conducts can be regulated to a specific direction
Implementation Method 2
thermal conductivity is different between the direction in which the irradiation window spreads and the direction of the thickness of the irradiation window
Implementation Method 3
electrons generated by the electron source are accelerated and made to collide with a target as an electron beam so that X-rays are generated
Implementation Method 4
X-rays are generated by making electrons collide with a target in a vacuumed atmosphere within an X-ray tube
Implementation Method 5
using materials like thermally anisotropic graphite or multilayer structures with varying thermal conductivities to direct heat flow selectively
Data Source
AI summary
An object of the invention is to provide an X-ray generator having a simple configuration where heat generated in the irradiation window can be prevented from conducting to a desired portion in accordance with the purpose of use, the method of use or the structure of the X-ray tube. In an X-ray generator for releasing X-rays generated by irradiating a target placed in a vacuumed atmosphere within an X-ray tube with an electron beam from an electron source through an irradiation window of the X-ray tube, the irradiation window has thermal anisotropy where the thermal conductivity is different between the direction in which the irradiation window spreads and the direction of the thickness of the irradiation window, and therefore, the thermal conductivity in the direction in which the heat from the irradiation window is desired not to conduct is made relatively smaller.