Segmented X-ray Target with Thermal Substrate
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Solution Overview
Problem
Laboratory x-ray sources face limitations in brightness due to heat generation from electron irradiation, with only about 1% of incident power converted into x-rays, leading to melting issues and reduced x-ray production efficiency.
Innovation Solution
An x-ray source with a thermally conductive substrate and embedded structures made of a different material, irradiated at a non-zero angle by electrons, to enhance x-ray generation and thermal management, allowing for a micropatterned x-ray beam suitable for Talbot-Lau interferometry configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If electrons irradiate a metal target to generate x-rays, then x-rays are produced, but most power is converted into heat causing melting and limiting brightness
Solution Approach 1:
The target is segmented into multiple discrete structures (e.g., posts, pillars, or rods) arranged in an array on the substrate. This segmentation distributes the electron beam energy across multiple separate structures rather than concentrating it on a continuous surface, reducing heat accumulation in any single location and preventing melting while maintaining x-ray generation efficiency
Solution Approach 2:
The target structures use different materials with optimized local properties: the substrate provides thermal conduction to dissipate heat, while the discrete structures use high atomic number materials for efficient x-ray generation. This local differentiation of material properties allows simultaneous heat management and x-ray production optimization
2Productivity
If electrons irradiate the target at normal incidence, then x-ray generation is efficient, but energy deposition is concentrated causing heat issues
Solution Approach 1:
The electron beam is directed at the target structures at a non-zero angle relative to the substrate normal, creating an asymmetric irradiation geometry. This angular incidence spreads the energy deposition path through multiple structures and increases the effective path length, improving x-ray generation while distributing thermal load more effectively across the target array
3Ease of manufacture
If a continuous metal target is used, then x-ray generation is straightforward, but heat dissipation is insufficient leading to melting
Solution Approach 1:
The continuous target material is replaced with discrete segmented structures arranged in an array on a substrate. This segmentation inherently improves heat dissipation by creating air gaps between structures that act as thermal insulators, preventing heat accumulation and melting while maintaining structural integrity and reliability
Solution Approach 2:
The target employs a composite structure combining a thermally conductive substrate material with discrete high atomic number structures. This composite design leverages the thermal management properties of the substrate while utilizing the x-ray generating properties of the discrete structures, achieving both ease of manufacture and improved reliability
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 increases the energy deposition in the x-ray generating structures, improving x-ray production efficiency and reducing heat-related issues, resulting in higher x-ray brightness and contrast for applications like medical imaging and microscopy.
Implementation Method 1
The substrate comprises a thermally conductive first material
Implementation Method 2
the at least one second material is configured to generate x-rays upon irradiation by electrons
Implementation Method 3
the metal target produces x-rays by creating holes in the inner core electron orbitals of the target atoms, which are then filled by electrons of the target with binding energies that are lower than the inner core electron orbitals, with concomitant generation of x-rays with energies that are characteristic of the target atoms
Implementation Method 4
an electron source configured to generate the electrons and to direct the electrons to impinge the target
Data Source
AI summary
An x-ray source and an x-ray interferometry system utilizing the x-ray source are provided. The x-ray source includes a target that includes a substrate and a plurality of structures. The substrate includes a thermally conductive first material and a first surface. The plurality of structures is on or embedded in at least a portion of the first surface. The structures are separate from one another and are in thermal communication with the substrate. The structures include at least one second material different from the first material, the at least one second material configured to generate x-rays upon irradiation by electrons having energies in an energy range of 0.5 keV to 160 keV. The x-ray source further includes an electron source configured to generate the electrons and to direct the electrons to impinge the target and to irradiate at least some of the structures along a direction that is at a non-zero angle relative to a surface normal of the portion of the first surface. The x-ray source further includes at least one optical element positioned such that at least some of the x-rays are transmitted through the first material and to or through the at least one optical element.