Cargo scanning
The examples and perspective in this article may not represent a worldwide view of the subject. (December 2010) |
Cargo scanning or non-intrusive inspection (NII) refers to non-destructive methods of inspecting and identifying goods in transportation systems. It is often used for scanning of
Radiography
Gamma-ray radiography
The systems provide good quality images which can be used for identifying cargo and comparing it with the manifest, in an attempt to detect anomalies. It can also identify high-density regions too thick to penetrate, which would be the most likely to hide nuclear threats.X-ray radiography
Dual-energy X-ray radiography
Dual-energy X-ray radiography[11]
Backscatter X-ray radiography
Backscatter X-ray radiography
Neutron activation systems
Examples of neutron activation systems include: pulsed fast neutron analysis (PFNA), fast neutron analysis (FNA), and thermal neutron analysis (TNA). All three systems are based on neutron interactions with the inspected items and examining the resultant gamma rays to determine the elements being radiated. TNA uses thermal neutron capture to generate the gamma rays. FNA and PFNA use fast neutron scattering to generate the gamma rays. Additionally, PFNA uses a pulsed collimated neutron beam. With this, PFNA generates a three-dimensional elemental image of the inspected item.
Passive radiation detectors
Muon tomography
Muon imaging was originally proposed and demonstrated by Alvarez.[13] The method was re-discovered and improved upon by a research team at Los Alamos National Laboratory,[14][15] muon tomography is completely passive, exploiting naturally occurring cosmic radiation. This makes the technology ideal for high throughput scanning of volume material where operators are present, such as at a marine cargo terminal. In these cases, truck drivers and customs personnel do not have to leave the vehicle or exit an exclusion zone during scanning, expediting cargo throughput.
Multi-mode passive detection systems (MMPDS), based upon muon tomography, are currently in use by Decision Sciences International Corporation at Freeport, Bahamas,[16] and the Atomic Weapons Establishment in the United Kingdom.[17] An MMPDS system has also been contracted by Toshiba to determine the location and the condition of the nuclear fuel in the Fukushima Daiichi Nuclear Power Plant.[18]
Gamma radiation detectors
Radiological materials emit gamma photons, which
They provide very little information on energy of detected photons, and as a result, they were criticized for their inability to distinguish gammas originating from nuclear sources from gammas originating from a large variety of benign cargo types that naturally emit radioactivity, including bananas,
Radiation originating from earth is also a major contributor to background radiation.
Another limitation of gamma radiation detectors is that gamma photons can be easily suppressed by high-density shields made from lead or steel,[4] preventing detection of nuclear sources. Those types of shields do not stop fission neutrons produced by plutonium sources, however. As a result, radiation detectors usually combine gamma and neutron detectors, making shielding only effective for certain uranium sources.
Neutron radiation detectors
Fissile materials emit neutrons. Some nuclear materials, such as the weapons usable plutonium-239, emit large quantities of neutrons, making neutron detection a useful tool to search for such contraband. Radiation Portal Monitors often use Helium-3 based detectors to search for neutron signatures. However, a global supply shortage of He-3[21] has led to the search for other technologies for neutron detection.
See also
References
- ^ "100% Cargo Scanning Passes Congress" article in "FedEx Trade Networks" (Aug. 02, 72007)
- ^ U.S. Azerbaijan Chamber of Commerce – SAIC'S VACIS(R) Cargo, Vehicle and Contraband Inspection Systems to Be Installed in Azerbaijan Archived 9 October 2007 at the Wayback Machine
- ^ Vartabedian, Ralph (15 July 2006). "U.S. to Install New Nuclear Detectors at Ports". Los Angeles Times.
- ^ a b c Waste, Abuse, and Mismanagement in Department of Homeland Security Contracts (PDF). United States House of Representatives. July 2006. pp. 12–13. Archived from the original (PDF) on 30 August 2007. Retrieved 10 September 2007.
- ^ http://containproject.com/ CONTAIN – Container Security Advanced Information Networking
- ^ a b "Technical Specifications of Mobile VACIS Inspection System". Archived from the original on 27 September 2007. Retrieved 1 September 2007.
- ^ a b "Technical Specifications of Mobile Rapiscan GaRDS Inspection System" (PDF). Retrieved 1 September 2007.
- ^ "Overview of VACIS P7500 Inspection System". Archived from the original on 9 October 2007. Retrieved 1 September 2007.
- ^ Jones, J. L.; Haskell, K. J.; Hoggan, J. M.; Norman, D. R. (June 2002). "ARACOR Eagle-Matched Operations and Neutron Detector Performance Tests" (PDF). Idaho National Engineering and Environmental Laboratory. Retrieved 1 September 2007.
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(help) - ^ Dan A. Strellis (4 November 2004). "Protecting our Borders while Ensuring Radiation Safety" (PDF of Powerpoint Presentation). Presentation to the Northern California Chapter of the Health Physics Society. Retrieved 1 September 2007.
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- ^ "Muon Tomography – Deep Carbon, MuScan, Muon-Tides". Boulby Underground Science Facility. Archived from the original on 15 October 2013. Retrieved 15 September 2013.
- ^ "Secrets of the pyramids"
- ^ ""Muon radiography" by Brian Fishbine from Los Alamos National Laboratory". Archived from the original on 20 December 2013. Retrieved 18 September 2007.
- ^ "Muons for Peace" by Mark Wolverton in Scientific American
- ^ "Dr. Stanton D. Sloane of Decision Sciences looks at how passive detection systems can play their part in protecting the global supply chain" by Cargo Security International
- ^ "Decision Sciences Awarded Atomic Weapons Establishment (AWE) Contract for Nuclear Detection System."
- ^ "Cosmic Rays to pinpoint Fukushima cores" by World Nuclear News
- ^ "Overview of Exploranium's AT-980 Radiation Portal Monitor (RPM)". Archived from the original on 9 October 2007. Retrieved 1 September 2007.
- ^ "Manual for Ludlum Model 3500-1000 Radiation Detector System" (PDF). Retrieved 1 September 2007.
- ^ Wald, M. (22 November 2009). "Shortage Slows a Program to Detect Nuclear Bombs". The New York Times.