Pulsed Neutron Explosive Detection with Silicon Correction
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Solution Overview
Problem
Current systems for detecting buried explosives face challenges in accurately identifying nitrogen-based and non-nitrogen-based explosives, particularly in varying soil types, due to background interference and false positives, which affect detection efficiency and reliability.
Innovation Solution
A vehicle-mounted system utilizing pulsed neutron elemental analysis with a deuterium-tritium neutron generator and an array of NaI detectors to capture and analyze gamma ray emissions, correcting for background signals from silicon and hydrogen to enhance detection accuracy and reduce false positives by measuring elemental concentrations of nitrogen, oxygen, carbon, and silicon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If neutron-responsive means are used for elemental analysis in explosives underground, then detection probability of buried explosives is improved, but background interference from soil elements (silicon, hydrogen) increases causing false positives
Solution Approach 1:
The detection system segments the gamma-ray spectrum into multiple energy ranges, with each range corresponding to specific elemental signatures. By analyzing gamma rays in different energy bands separately, the system can identify nitrogen-based explosives, non-nitrogen-based explosives, and soil elements (silicon, hydrogen) independently, thereby distinguishing target signals from background interference.
Solution Approach 2:
The system employs feedback mechanisms where the detected gamma-ray signals from soil elements (silicon, hydrogen) are used to dynamically adjust and correct the detection algorithm. The processor compares measured elemental concentrations against expected background levels and applies corrections to reduce false positives while maintaining high detection probability for buried explosives.
2Measurement precision
If multiple elemental concentrations are measured to reduce false positives, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The neutron-responsive means are designed to simultaneously detect multiple elements (nitrogen, silicon, hydrogen, oxygen, carbon) across different gamma-ray energy ranges. This multi-functional capability allows the system to perform both target detection and background characterization using the same hardware, avoiding the need for separate measurement systems for each element.
Solution Approach 2:
The system merges the detection of multiple elements and the correction for background interference into a single integrated processing step. The processor simultaneously analyzes gamma-ray signals from all measured elements and applies combined corrections to determine the presence of explosives, reducing overall system complexity compared to sequential or separate measurement approaches.
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
The system achieves a 99.5% detection probability of nitrogen-based explosives and effectively reduces false positives, enabling rapid detection of buried explosives up to 1 meter deep with minimal interference from soil types, while ensuring operator safety through controlled radiation exposure.
Implementation Method 1
a deuterium-tritium neutron generator
Implementation Method 2
an array of NaI detectors to capture and analyze gamma ray emissions
Data Source
AI summary
A system and method are described for capturing and analyzing gamma rays from neutron excitation of a region in 3-space being analyzed for explosives. A processor analyzes the results, determining whether underground explosives are present in a particular region of the ground. In one embodiment, one gamma ray energy band is used to infer an amount of silicon in the region, while another indicates the combined amount of silicon and nitrogen. The concentration of nitrogen in the region is inferred and used to trigger an “explosive found” or a “no explosive found” signal. In other embodiments, the system or method uses inferences about other elemental constituents of the ground being examined, sometimes taking as input analyzes from prior scans, and providing output indicating the likelihood of the presence of explosives in the region.