X-ray Tube Diaphragm with Segmented Aperture for Stray Radiation Control
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Solution Overview
Problem
X-ray tubes, particularly microfocus X-ray tubes, suffer from image quality impairment due to a bright circular disc caused by scattered X-radiation when electrons strike the metal diaphragm body, which is exacerbated by high thermal loads leading to coating peeling and inefficiencies in existing collimator designs.
Innovation Solution
A diaphragm divided into two parts, with the additional body made of a material with a lower atomic number than the base body, arranged such that the electron beam strikes the lower atomic number material near the electron source, reducing stray radiation and using a conical shape to prevent electrons from hitting the higher atomic number material, thus minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the diaphragm body is made of metal with high atomic number to ensure high-temperature resistance, then thermal stability is improved, but stray radiation increases causing bright circular disc in images
Solution Approach 1:
The diaphragm is divided into two separate components: a base body made of high-atomic-number metal for thermal stability, and an additional body made of low-atomic-number material positioned in the electron beam path to reduce stray radiation. This segmentation allows each component to fulfill its specific function without compromise.
Solution Approach 2:
Different regions of the diaphragm system are assigned different material properties: the additional body (exposed to electron beam) uses low-atomic-number material to minimize bremsstrahlung, while the base body (handling thermal load) uses high-atomic-number metal for thermal resistance. Each location has optimized material quality for its specific role.
2Object-generated harmful factors
If a coating with low atomic number is applied to the metal diaphragm to reduce stray radiation, then stray radiation is reduced, but the coating peels under high thermal load
Solution Approach 1:
Instead of coating the metal diaphragm with low-atomic-number material, the invention uses two separate uncoated components: a metal base body and an additional low-atomic-number body. This eliminates the coating adhesion problem while achieving the same radiation reduction effect.
Solution Approach 2:
The additional body made of low-atomic-number material acts as an intermediary element positioned between the electron beam and the metal base body. It absorbs or redirects stray radiation before it reaches the target, while the metal base body handles thermal loads without requiring a coating.
3Shape
If the diaphragm aperture narrows in the beam direction to improve collimation, then beam restriction is improved, but electrons may still strike the diaphragm body causing stray radiation
Solution Approach 1:
The additional body is positioned specifically at the entrance side of the diaphragm aperture where electron beam interaction occurs. This local placement ensures that electrons are blocked or redirected before they can reach the metal base body, while the aperture geometry maintains proper collimation function.
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 effectively reduces stray radiation penetration, preventing image errors and maintaining high temperature resistance while avoiding coating peeling, by using materials like graphite for the additional body and metals like molybdenum for the base body, ensuring heat resistance and minimal magnetic interference.
Implementation Method 1
when the electrons strike the diaphragm body short-wave X-radiation forms which penetrates the target
Data Source
AI summary
A diaphragm for restricting a cross section of an electron beam of an X-ray tube includes a base body made of a first material, which has a first cylindrical or conical diaphragm aperture, and an additional body made of a second material, which has a second cylindrical or conical diaphragm aperture. The additional body in the installed state is arranged on the side near the electron source, wherein the atomic number of the first material is greater than the atomic number of the second material. The diameters of the diaphragm apertures at the end far from the electron source are not smaller than at the end near the electron source, and the second diaphragm aperture at its end far from the electron source lies completely inside the first diaphragm aperture at its end near the electron source.