3D Atomic Number Imaging via X-ray Scattering Coincidence
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Solution Overview
Problem
Conventional methods for inspecting dangerous goods, such as explosives, chemicals, and nuclear materials, face challenges in accurately detecting these items due to limitations in x-ray and neutron inspection technologies, including integration information along a single path, interference from background photons, and poor sensitivity and resolution.
Innovation Solution
An article inspection device that uses a combination of x-ray machines, collimation units, and scattering detector arrays to form a three-dimensional image by dividing the transmission cross-section into sub-regions and using coincidence counters to differentiate between pair production and Compton-effect scattering photons, allowing for precise atomic number determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If x-ray transmission solution is used to obtain attenuation information along the transmission path, then the inspection process is simple, but it cannot discriminate between thinner high atomic number articles and thicker low atomic number articles, resulting in poor detection accuracy for nuclear materials
Solution Approach 1:
The patent divides the transmission cross-section into multiple sub-regions and uses multiple scattering detector modules arranged in a matrix to detect photons from different spatial locations independently. This segmentation enables the system to obtain spatially resolved information rather than integrated path information, allowing discrimination of atomic numbers at different positions within the article.
Solution Approach 2:
The patent transitions from one-dimensional attenuation measurement along a single transmission path to two-dimensional spatial mapping by dividing the cross-section into sub-regions and using multiple detectors arranged in a matrix. This dimensional expansion provides spatial resolution that enables discrimination of materials at different locations.
2Measurement precision
If conventional nuclear resonance fluorescence solution is used to obtain fingerprint information of atomic nucleus, then the inspection sensitivity can be improved, but the article generates great number of scattering photons after being irradiated by x-rays, causing background interference
Solution Approach 1:
The patent extracts and separately processes coincidence events from the total photon signal. By identifying photon pairs that arrive at detector modules in coincidence (within a specific time window), the system separates the useful resonance fluorescence signal from background scattering photons, effectively removing the harmful background interference while retaining the sensitive fingerprint information.
Solution Approach 2:
The patent uses coincidence counting as a feedback mechanism to identify and select valid photon events. The coincidence timing information provides feedback that distinguishes true resonance fluorescence photons from scattered background photons, enabling the system to filter signals based on temporal correlation characteristics.
3Measurement precision
If neutron transmission solution is used to detect materials containing hydrogen, then the detection of hydrogen-containing materials is improved, but it cannot obtain spatial distribution information of chemical elements, resulting in inability to detect hidden nuclear materials
Solution Approach 1:
The patent segments the detection field into multiple sub-regions and uses corresponding detector modules to independently measure photon interactions in each region. This spatial segmentation preserves location information, enabling the system to map the spatial distribution of atomic numbers and chemical elements within the article, unlike conventional neutron transmission that provides only integrated information.
4Measurement precision
If elementary analysis solution using neutron reaction is used to discriminate different elements, then the element discrimination capability is improved, but the system requires very complicated gamma rays spectra interpretation and nanosecond width neutron pulse production, making the device complex
Solution Approach 1:
The patent replaces the complex mechanical and computational systems required for conventional neutron-based element analysis with a simplified x-ray scattering system using coincidence counting. Instead of requiring nanosecond pulse production and complicated gamma spectra interpretation, the system uses temporal coincidence detection of scattered photons, which is easier to implement and interpret while achieving similar element discrimination capability.
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 enables the formation of a three-dimensional image and improves the detection sensitivity and accuracy of atomic numbers within the article, overcoming the limitations of existing technologies by providing detailed spatial information.
Implementation Method 1
attenuation information of x-rays transmitting through an article to be inspected is firstly detected by use of a transmission detector array
Implementation Method 2
detecting annihilation photons and Compton-effect scattering photons from the article when irradiated by the x-rays
Implementation Method 3
differentiate between pair production and Compton-effect scattering photons
Data Source
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AI summary
The present invention discloses an article inspection device, comprising: a x-ray machine, a collimation unit, a transmission detector array and at least one scattering detector array. Each of the at least one scattering detector array comprising a plurality of same scattering detector modules arranged in a matrix of i-rows and j-columns. A transmission cross section of the article transmitted by the x-rays is divided into a plurality of same sub-regions arranged in a matrix of i-rows and j-columns. The plurality of scattering detector modules arranged in i-rows and j-columns correspond to the plurality of sub-regions arranged in i-rows and j-columns one by one for detecting pair production effect annihilation photons and Compton-effect scattering photons from the respective sub-regions. Obtaining atomic numbers of the respective sub-regions based on a ratio of the pair production effect annihilation photon count to the Compton-effect scattering photon count, so as to form a three-dimensional image of the article. In addition, the present invention further discloses an article inspection method.