Muon Tomography for Shielded Nuclear Material Detection
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Solution Overview
Problem
Current border surveillance systems face challenges in detecting small quantities of nuclear materials due to effective shielding, which obscures neutron and gamma ray signatures, making it difficult to detect nuclear threats at border crossings.
Innovation Solution
A particle detection system utilizing cosmic ray-produced muons and position-sensitive drift tubes to track incoming and outgoing charged particles, providing a tomographic profile that reveals the presence of high atomic number materials, including nuclear materials, through multiple scattering analysis, thereby combining cosmic ray radiography with gamma radiation detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional gamma or X-ray detectors are used to detect nuclear materials, then detection capability is improved, but shielding materials can obscure the nuclear signature making detection difficult
Solution Approach 1:
The patent uses cosmic ray muons as an intermediary detection method. Instead of directly detecting gamma rays from nuclear materials (which are blocked by shielding), the system detects muons that pass through the shielding and cargo. The muons serve as a mediator that can penetrate materials that block conventional radiation signatures, allowing indirect detection of nuclear materials behind shielding.
Solution Approach 2:
The patent replaces the conventional electromagnetic radiation detection system (gamma/X-ray detectors) with a cosmic ray muon detection system. This substitution uses naturally occurring high-energy muons from cosmic rays instead of artificial radiation sources, enabling detection through shielding that would block conventional radiation-based methods.
2Reliability
If high resolution gamma or X-ray detectors are deployed at border crossings, then nuclear material detection reliability is improved, but system complexity and cost increase
Solution Approach 1:
The system uses naturally occurring cosmic ray muons as the radiation source, eliminating the need for artificial radiation sources, complex shielding, and sophisticated detector systems. The environment provides the detection source automatically, simplifying the overall system while maintaining detection capability.
Solution Approach 2:
The patent changes the detection parameter from gamma-ray energy spectra analysis to muon trajectory and scattering angle measurements. This parameter change simplifies the detection methodology, as muon scattering patterns provide direct information about high-Z materials without requiring complex spectral analysis.
3Measurement precision
If active radiation sources are used for scanning cargo, then detection capability is improved, but radiation safety concerns and system complexity increase
Solution Approach 1:
The system utilizes cosmic ray muons that naturally bombard the Earth's atmosphere, providing a continuous, free radiation source without human intervention. This eliminates concerns about radioactive source safety, storage, and disposal while providing sufficient flux for detection applications.
Solution Approach 2:
The patent converts potentially harmful cosmic radiation into a beneficial detection tool. While cosmic rays are high-energy radiation that can be harmful, the system harnesses this same radiation to detect nuclear materials, turning an environmental hazard into a security asset.
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 robust, cost-effective detection of nuclear threats with reduced complexity, allowing for passive scanning of vehicles and cargo without delivering additional radiation, effectively distinguishing high-density shielding materials and nuclear materials from ordinary objects.
Implementation Method 1
track incoming and outgoing charged particles, providing a tomographic profile that reveals the presence of high atomic number materials, including nuclear materials, through multiple scattering analysis
Implementation Method 2
position-sensitive drift tubes to track incoming and outgoing charged particles
Implementation Method 3
combining cosmic ray radiography with gamma radiation detection
Data Source
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AI summary
Techniques, apparatus and systems for detecting particles such as muons. In one implementation, a monitoring system has a cosmic ray-produced charged particle tracker with a plurality of drift cells. The drift cells, which can be for example aluminum drift tubes, can be arranged at least above and below a volume to be scanned to thereby track incoming and outgoing charged particles, such as cosmic ray-produced muons, whilst also detecting gamma rays. The system can selectively detect devices or materials, such as iron, lead, gold and/or tungsten, occupying the volume from multiple scattering of the charged particles passing through the volume and can also detect any radioactive sources occupying the volume from gamma rays emitted therefrom. If necessary, the drift tubes can be sealed to eliminate the need for a gas handling system. The system can be employed to inspect occupied vehicles at border crossings for nuclear threat objects.