Compact Laminography X-Ray Detector with Microfocus Source
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Solution Overview
Problem
Conventional X-ray computed laminography systems face challenges with large size, weight, and thermal heating issues due to high geometric magnification and close sample-source distances, which affect image resolution and fidelity, and lack efficient detection of high-energy x-rays.
Innovation Solution
The system employs a detector with smaller effective pixel sizes (0.3 micron to 20 microns), reduced geometric magnification, and increased source-sample distances to minimize thermal heating, using thin scintillators and optimized scintillator materials for improved contrast and resolution, allowing for a more compact design and reduced artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high geometric magnification is used to achieve sub-micron effective pixel sizes, then image resolution is improved, but system size and weight increase
Solution Approach 1:
The patent changes the operating parameters by using a microfocus x-ray source with small focal spot size (0.1-10 microns) and positioning the sample close to the source (1-50 mm distance), achieving high resolution without requiring large geometric magnification ratios. This parameter optimization allows sub-micron resolution while keeping the system compact.
Solution Approach 2:
The patent replaces the traditional mechanical magnification system (requiring large source-detector distances) with an optical coupling system using a microscope objective lens. The lens captures x-rays from the microfocus source and focuses them onto the detector, achieving magnification through optical means rather than geometric distance, thereby reducing system size.
2Length of moving object
If close sample-source distance is used to reduce system size, then thermal heating of sample increases
Solution Approach 1:
The patent introduces an intermediary cooling system between the x-ray source and the sample. This includes a cold plate or liquid nitrogen cooling system that acts as a thermal sink, removing heat from the sample area and preventing thermal heating even when the sample is positioned close to the source.
Solution Approach 2:
The patent uses a vacuum environment as an inert atmosphere to eliminate convective heating from air molecules. The vacuum chamber removes gas-phase thermal transfer mechanisms, allowing close sample-source positioning without significant thermal heating from the x-ray source.
3Reliability
If thick scintillator materials are used to detect high-energy x-rays, then detection efficiency is improved, but image contrast and resolution decrease
Solution Approach 1:
The patent optimizes the scintillator thickness parameter to a specific range (50-200 microns) that balances x-ray detection efficiency with image quality. This optimized thickness range allows sufficient detection of high-energy x-rays while maintaining adequate light output for high contrast and resolution imaging.
Solution Approach 2:
The patent uses composite scintillator materials such as cesium iodide (CsI) or lutetium aluminum garnet (LuAG) that have high atomic number elements for efficient high-energy x-ray detection. These composite materials provide both high detection efficiency and high light yield, achieving both detection reliability and image quality simultaneously.
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 results in a more compact and lightweight system with improved resolution and reduced thermal instability, enabling higher contrast imaging and accommodating various sample types, while maintaining or exceeding the spatial resolution of conventional systems.
Implementation Method 1
The at least one optical subsystem comprises a scintillator having a thickness that is substantially parallel to the x-ray propagation axis. The scintillator is configured to generate visible light in response to x-rays impinging the scintillator.
Implementation Method 2
The at least one optical subsystem further comprises at least one optical lens configured to receive the visible light from the scintillator and to focus the visible light into the two-dimensional image.
Implementation Method 3
a transmission x-ray source configured to generate x-rays at an x-ray source focal spot
Data Source
AI summary
An x-ray computed laminography imaging system includes a transmission x-ray source configured to generate x-rays, at least some of the x-rays propagate along an x-ray propagation axis through a region of interest of an object. The system further includes a stage assembly configured to rotate the object about a rotation axis extending through the region of interest. The system further includes at least one x-ray detector configured to intercept at least some of the x-rays propagating along the x-ray propagation axis. The at least one x-ray detector includes a scintillator, at least one optical lens, and two-dimensional pixelated imaging circuitry. The scintillator has a thickness that is substantially parallel to the x-ray propagation axis and the at least one optical lens is configured to receive visible light from the scintillator and to focus the visible light into a two-dimensional image. The at least one optical lens has a depth of focus, and the thickness of the scintillator is in a range of 1 to 20 times the depth of focus.