Liquid Lead-Bismuth Target X-Ray System Heat Management
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Solution Overview
Problem
Conventional X-ray generation methods face challenges in achieving high resolution and high power output simultaneously due to overheating issues and mechanical complexities, particularly in maintaining small focal spots for improved imaging resolution.
Innovation Solution
A system utilizing a liquid target material with a high atomic number, such as lead bismuth eutectic, within a vacuum chamber, where the electron beam is focused through a thin diamond window assembly, allowing for continuous flow and improved heat management, thereby increasing X-ray beam generation intensity and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a small focal spot is used to improve imaging resolution, then imaging resolution is improved, but the power must be lowered due to heat accumulation
Solution Approach 1:
The patent employs a rotating target wheel with multiple focal spots arranged in a circle. The target rotates continuously, dynamically distributing the electron beam impact across multiple locations. This dynamic rotation allows each focal spot to cool down while the system maintains high overall power output by switching between multiple spots, resolving the contradiction between small focal spot size and high power capability.
Solution Approach 2:
The target is segmented into multiple discrete focal spots (at least three) arranged around the rotation axis. Each focal spot can be independently utilized, allowing the system to divide the total power load across multiple segments. This segmentation enables high resolution imaging (using small individual spots) while maintaining high overall power (by distributing energy across multiple spots over time).
2Temperature
If a rotating target is used to distribute heat, then heat management is improved, but mechanical complexity increases
Solution Approach 1:
The patent employs a fluid target system where liquid or gas flows through a chamber exposed to the electron beam. The fluid continuously moves, carrying heat away from the interaction region without requiring mechanical rotation. This fluid dynamics approach achieves heat distribution while eliminating complex rotating mechanical structures, using only pumps and flow control mechanisms.
Solution Approach 2:
The system changes the physical state of the target from solid (requiring rotation) to liquid or gas (flowing). This parameter change allows the target material to continuously refresh and dissipate heat through flow rather than rotation. The fluid target can be pumped through the interaction zone and replaced, providing heat management without mechanical complexity of rotating assemblies.
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 system enhances X-ray beam generation intensity by approximately 12% compared to tungsten targets, reducing imaging time and improving resolution, while minimizing overheating and mechanical complexity.
Implementation Method 1
In a first route, named Bremsstrahlung radiation, electromagnetic radiation is produced by the deceleration of a charged particle when deflected by another charged particle, typically an electron by an atomic nucleus. The moving particle loses kinetic energy, which is converted into radiation (i.e., a photon), thus satisfying the law of conservation of energy.
Implementation Method 2
In a second route, named characteristic radiation, X-rays are produced when an element is bombarded with high-energy particles, which can be photons, electrons or ions (such as protons). When the incident particle strikes a bound electron (the target electron) in an atom, the target electron is ejected from the inner shell of the atom. After the electron has been ejected, the atom is left with a vacant energy level, also known as a core hole. Outer-shell electrons then fall into the inner shell, emitting quantized photons with an energy level equivalent to the energy difference between the higher and lower states.
Data Source
AI summary
A system for generating X-ray beams from a liquid target includes a vacuum chamber, a diamond window assembly, an electron source, a target material flow system, and an X-ray detector/imager. An electron beam from the electron source travels through the diamond window assembly and into a dynamic target material of the flow system. Preferably, the dynamic target material is lead bismuth eutectic in a liquid state. Upon colliding with the dynamic target material, X-rays are generated. The generated X-rays exit through an X-ray exit window to be captured by the X-ray detector/imager. Since the dynamic target material is constantly in fluid motion within a pipeline of the flow system, the electron beam always has a new target area which is at a controlled operational temperature and thus, prevents overheating issues. By providing a small focus area for the electron beams, the overall imaging resolution of the X-rays is also improved.