Transmissive X-Ray Target Structure for Crack-Stable Tube Output
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Solution Overview
Problem
Existing X-ray generation tubes using polycrystalline diamond substrates suffer from issues such as electric discharge, anode current lowering, and X-ray output variations due to crack formation and thermal stress, which are exacerbated by asymmetrical crystal grain diameter distributions and thermal expansion differences.
Innovation Solution
The use of a polycrystalline diamond substrate with a targeted crystal grain diameter distribution, where the target layer is supported on a surface with a smaller average crystal grain diameter, mitigates crack formation and reduces electric discharge and anode current fluctuations by stabilizing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a monocrystalline diamond substrate is used, then X-ray transmissivity is improved, but manufacturing cost and difficulty increase significantly
Solution Approach 1:
The patent uses a polycrystalline diamond substrate with uniformly controlled crystal grain sizes (first surface: 1-10 μm, second surface: 10-50 μm) to achieve homogeneous structural properties that provide sufficient X-ray transmissivity while being manufacturable through conventional sintering processes rather than requiring monocrystalline growth techniques
Solution Approach 2:
The patent changes the structural parameters of the diamond substrate by controlling crystal grain size distribution across surfaces and adjusting porosity (30-70%) to optimize the balance between X-ray transmissivity and mechanical strength, enabling polycrystalline diamond to replace monocrystalline diamond
2Ease of manufacture
If a polycrystalline diamond substrate with uniform fine crystal grains is used, then manufacturing ease is improved, but X-ray transmissivity and electron beam scattering performance deteriorate
Solution Approach 1:
The patent applies asymmetric crystal grain distribution where the first surface has finer grains (1-10 μm) for electron beam interaction and the second surface has coarser grains (10-50 μm) for X-ray transmission, creating functional asymmetry that resolves the contradiction between manufacturability and performance
Solution Approach 2:
Different regions of the substrate are assigned different crystal grain sizes optimized for their specific functions: the first surface region is optimized for electron beam scattering with finer grains, while the second surface region is optimized for X-ray transmission with coarser grains and higher porosity
3Temperature
If the target layer is made thinner to reduce heat accumulation, then heat resistance is improved, but target layer strength and lifespan deteriorate
Solution Approach 1:
The patent introduces a porous diamond intermediate layer between the thin target layer and the substrate that acts as a heat sink and mechanical support, enabling the target layer to be made thinner for heat dissipation while the diamond layer provides the necessary structural strength and thermal management
Solution Approach 2:
The patent uses a porous diamond layer with controlled porosity (30-70%) that provides both thermal management capabilities for heat dissipation and mechanical support structure, allowing the thin target layer to maintain strength while improving heat resistance
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 enhances the reliability of X-ray generation by minimizing crack development and maintaining consistent anode current, thereby improving the stability and performance of the X-ray generation tube.
Implementation Method 1
a transmissive substrate (21) including polycrystalline diamond and configured to support the target layer (22)
Implementation Method 2
an electron beam is made to accelerate toward a target material, and X-rays are generated by decelerating the electron beam with the target material
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A transmissive-type target includes a target layer (22) including a target material, and a transmissive substrate (21) including polycrystalline diamond and configured to support the target layer (22). The transmissive substrate (21) includes a first surface (24) having a first average crystal grain diameter and a second surface (25) opposite the first surface (24) and having a second average crystal grain diameter larger than the first average crystal grain diameter. The target layer (22) is supported by any one of the first surface (24) and the second surface (25).