Liquid-Jet X-Ray Source Debris Reduction via Focused Electron Beam
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Solution Overview
Problem
Current compact electron-impact x-ray sources are limited by thermal effects, restricting the brightness and power density of the x-ray source, and the use of liquid-jet anodes faces challenges with debris emission when attempting to increase power density.
Innovation Solution
Employing an electron beam with a full width at half maximum (FWHM) that is about half the transverse dimension of the target jet or less, which creates a shielding effect to reduce debris and increase effective power density by focusing the electron beam to a smaller size compared to the target jet, allowing for higher thermal load without increasing jet speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the electron beam spot size is reduced to increase power density, then x-ray brightness is improved, but debris emission increases
Solution Approach 1:
The patent applies local quality by creating a temperature gradient across the target jet cross-section, with the center region (where the electron beam impacts) being hottest and the periphery being cooler. This spatial variation in temperature allows the hot central region to generate high x-ray brightness while the cooler peripheral regions suppress debris emission, effectively decoupling these two previously conflicting requirements.
2Object-generated harmful factors
If the liquid jet transverse dimension is reduced to maintain shielding effect, then debris is reduced, but the target area for x-ray generation is limited
Solution Approach 1:
The patent resolves this contradiction by transitioning from a two-dimensional area constraint to a three-dimensional volume utilization. The electron beam is focused to a small spot size (maintaining the shielding effect) but can be positioned at multiple locations along the length of the liquid jet. This allows the system to maintain a small interaction cross-section (reducing debris) while utilizing the full volume of the liquid jet target (maintaining or increasing total x-ray generation area).
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 significantly reduces debris production and enhances x-ray brightness by maintaining high power density while minimizing thermal limitations, enabling increased x-ray production without the need for extreme jet speeds.
Implementation Method 1
As the electrons impact the target they lose energy in one of two ways: either they can be decelerated in the electric field close to an atomic nucleus and emit continuous bremsstrahlung radiation
Implementation Method 2
or they can knock out an inner-shell electron, resulting in the emission of a characteristic x-ray photon when the vacancy is filled
Implementation Method 3
The brightness of current state-of-the-art compact electron-impact x-ray sources is limited by thermal effects in the anode
Data Source
Figure 1
Figure 2~3
AI summary
A method for generating x-ray radiation, comprising the steps of forming a target jet by urging a liquid substance under pressure through an outlet opening, the target jet propagating through an area of interaction; and directing at least one electron beam onto the target jet in the area of interaction such that the electron beam interacts with the target jet to generate x-ray radiation; wherein the full width at half maximum of the electron beam in the transverse direction of the target jet is about 50% or less of the target jet transverse dimension. A system for carrying out the method is also disclosed.