X-Ray Source Difference Imaging for Secondary Radiation Compensation
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Solution Overview
Problem
Secondary radiation in X-ray sources, originating from interactions within the system, adversely affects image quality by causing well-defined spots, blurring, and ring-like features, which existing compensation methods fail to adequately address when samples are present.
Innovation Solution
Record two images, one with the electron beam directed to the target and one to locations where only secondary radiation is emitted, and generate a difference image to eliminate the secondary radiation's influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flat field correction is used to compensate for secondary radiation, then the influence of secondary radiation is reduced during calibration, but the compensation fails when samples are present because the assumption of uniform illumination is not valid
Solution Approach 1:
The patent applies preliminary action by performing calibration measurements without samples to establish baseline secondary radiation characteristics. These pre-acquired images are stored and later subtracted from sample images to compensate for secondary radiation effects, enabling the system to handle both calibration and sample imaging scenarios.
Solution Approach 2:
The patent segments the imaging process into distinct phases: calibration phase (without samples) and measurement phase (with samples). By separating these phases and treating secondary radiation compensation as an independent step, the system can apply different procedures optimized for each phase while maintaining overall effectiveness.
2Object-affected harmful factors
If mechanical design and material selection are used to reduce secondary radiation, then the amount of secondary radiation is reduced, but these methods cannot completely eliminate it and require additional complexity in system design
Solution Approach 1:
The patent extracts secondary radiation effects from the overall imaging process by acquiring separate calibration images that contain only secondary radiation (without samples). These extracted secondary radiation components are then subtracted from sample images, effectively removing the harmful effect without requiring complex mechanical or material modifications.
Solution Approach 2:
The patent converts the harmful secondary radiation into a useful calibration signal. By intentionally measuring secondary radiation separately during calibration and using it for compensation, the system transforms what was previously a detrimental effect into a beneficial tool for improving image quality.
3Measurement precision
If scattered X-ray radiation compensation is performed by simulation, then scattered radiation can be compensated, but it is not evident how to obtain an image created only from scattered radiation
Solution Approach 1:
The patent creates a copy of the secondary radiation signal by acquiring calibration images without samples. These calibration images serve as templates or copies of the secondary radiation characteristics, which can then be subtracted from sample images to compensate for scattered and secondary radiation effects without requiring complex simulations.
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 method effectively reduces secondary radiation artifacts, enhancing image clarity and accuracy by isolating and subtracting secondary radiation components from the final image.
Implementation Method 1
X-ray radiation is generated in an X-ray source by an electron beam impacting a target. Typically, some secondary radiation is also created by electron beam interactions within the system, e.g. with an aperture (a beam-limiting element for the electron beam) and/or a target substrate.
Implementation Method 2
a target arranged to produce X-ray radiation upon impact by the electron beam
Data Source
AI summary
An X-ray imaging system is disclosed, comprising an X-ray source; a sample position; a detector arranged to detect X-ray radiation downstream of said sample position; wherein said X-ray source comprises an electron source arranged to provide an electron beam; a target arranged to produce X-ray radiation upon impact by said electron beam, the target comprising a substrate and a target layer at least partly covering said substrate, wherein said target layer is arranged to produce X-ray radiation upon impact by said electron beam; means for directing the electron beam to a first position on said target layer and a second position selected from a position on said target at which the electron beam impacts directly upon the substrate and a position on an electron beam dump arranged so that substantially no X-ray radiation created by interaction between the electron beam and the electron beam dump reaches the detector; a controller arranged to record, using said detector, a first image with the electron beam directed to said first position, and a second image with the electron beam directed to said second position, and generate a difference image between the first image and the second image. A method for X-ray imaging is also disclosed.