Cargo scanning: Difference between revisions

'''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 [[intermodal freight transport|intermodal freight]] [[Intermodal container|shipping container]]s. In the US it is spearheaded by the [[Department of Homeland Security]] and its [[Container Security Initiative]] (CSI) trying to achieve one hundred percent cargo scanning by 2012<ref>[http://ftn.fedex.com/news/NewsBulletinDisplay.jsp?url=080207&lang=en "100% Cargo Scanning Passes Congress" article in "FedEx Trade Networks" (Aug. 02, 72007)]</ref> as required by the [[US Congress]] and recommended by the [[9/11 Commission]]. In the US the main purpose of scanning is to detect [[special nuclear material]]s (SNMs), with the added bonus of detecting other types of suspicious cargo. In other countries the emphasis is on manifest verification, tariff collection and the identification of contraband.<ref>[http://www.usacc.org/content.php?id=2713&type=news U.S. Azerbaijan Chamber of Commerce -– SAIC'S VACIS(R) Cargo, Vehicle and Contraband Inspection Systems to Be Installed in Azerbaijan<!-- Bot generated title -->] {{webarchive |url=https://web.archive.org/web/20071009143647/http://www.usacc.org/content.php?id=2713&type=news |date=9 October 9, 2007 }}</ref> In February 2009, approximately 80% of US incoming containers were scanned.<ref>{{cite news| url=http://articles.latimes.com/2006/jul/15/nation/na-radiation15 | work=The Los Angeles Times | title=U.S. to Install New Nuclear Detectors at Ports | first=Ralph | last=Vartabedian | date=15 July 15, 2006}}</ref><ref name=hor/> In order toTo bring that number to 100% researchers are evaluating numerous technologies, described in the following sections.<ref>http://containproject.com/ CONTAIN -– Container Security Advanced Information Networking</ref>

[[Gamma-ray]] [[radiography]] systems capable of scanning trucks usually use [[cobalt-60]] or [[caesium-137]]<ref name='mv'>{{cite web|title=Technical Specifications of Mobile VACIS Inspection System |url=http://www.saic.com/products/security/mobile-vacis/mobile-tech.html |accessdate=Sep1 September 2007 |url-status=dead |archiveurl=https://web.archive.org/web/20070927014213/http://www.saic.com/products/security/mobile-vacis/mobile-tech.html |archivedate=2007-09-27 September 2007 }}</ref> as a radioactive source and a vertical tower of gamma [[detectors]]. This [[gamma camera]] is able to produce one column of an image. The horizontal dimension of the image is produced by moving either the truck or the scanning hardware. The cobalt-60 units use gamma [[photons]] with a mean energy 1.25&nbsp;[[mega electronvolt|MeV]], which can penetrate up to 15–18&nbsp;cm of steel.<ref name='mv'/><ref name='mr'>{{cite web| title =Technical Specifications of Mobile Rapiscan GaRDS Inspection System|url=http://www.rapiscansystems.com/datasheets/Rapiscan_GaRDSMobile_Screen.pdf| accessdate = Sep1 September 2007 }}</ref> 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 is similar to gamma-ray radiography but instead of using a radioactive source, it uses a [[High energy X-rays|high-energy]] [[bremsstrahlung]] spectrum with energy in the 5-105–10&nbsp;MeV range<ref>{{cite web|title=Overview of VACIS P7500 Inspection System |url=http://www.saic.com/products/security/vacis-p/ |accessdate=Sep1 September 2007 |url-status=dead |archiveurl=https://web.archive.org/web/20071009032119/http://www.saic.com/products/security/vacis-p/ |archivedate=9 October 2007-10-09 }}</ref><ref>{{cite journal|author1=Jones, J. L. |author2=Haskell, K. J. |author3=Hoggan, J. M. |author4=Norman, D. R. | title =ARACOR Eagle-Matched Operations and Neutron Detector Performance Tests| publisher =Idaho National Engineering and Environmental Laboratory| date =June 2002| url =http://www.inl.gov/technicalpublications/Documents/3310854.pdf| format =PDF| accessdate =Sep1 September 2007 }}</ref> created by a [[linear particle accelerator]] (LINAC). Such X-ray systems can penetrate up to 30–40&nbsp;cm of steel in vehicles moving with velocities up to 13&nbsp;km/h. They provide higher penetration but also cost more to buy and operate.<ref name='mr'/> They are more suitable for the detection of [[special nuclear material]]s than gamma-ray systems. They also deliver about 1000 times higher dose of radiation to potential [[stowaway]]s.<ref>{{cite journal| author =Dan A. Strellis| title =Protecting our Borders while Ensuring Radiation Safety| place =Presentation to the Northern California Chapter of the Health Physics Society| date =4 November 2004-11-04| url =http://hpschapters.org/ncchps/Inspection_Systems_at_POE.pdf| format =PDF of Powerpoint Presentation| accessdate = Sep1 September 2007}}</ref>

Dual-energy X-ray radiography<ref>{{cite journal| last =Ogorodnikov | first =S.|author2=Petrunin, V.| year =2002| title =Processing of interlaced images in 4-104–10 MeV dual energy customs system for material recognition| journal =[[Physical Review Special Topics: Accelerators and Beams]]| volume =5 | issue = 10 | page =104701| doi =10.1103/PhysRevSTAB.5.104701|bibcode = 2002PhRvS...5j4701O }}</ref>

[[Muon tomography]] is a technique that uses [[cosmic ray]] [[muons]] to generate three-dimensional images of volumes using information contained in the [[Coulomb scattering]] of the muons. Since muons are much more deeply penetrating than [[X-rays]], muon [[tomography]] can be used to image through much thicker material than x-ray based tomography such as [[CT scanning]]. The muon [[flux]] at the Earth's surface is such that a single muon passes through a volume the size of a human hand per second.<ref name="Muon Tomography - Deep Carbon, MuScan, Muon-Tides">{{cite web|url=http://www.stfc.ac.uk/Boulby/Projects/MuonTomography/39350.aspx|publisher=Boulby Underground Science Facility|accessdate=15 September 2013|title=Muon Tomography -– Deep Carbon, MuScan, Muon-Tides|archive-url=https://web.archive.org/web/20131015220751/http://www.stfc.ac.uk/Boulby/Projects/MuonTomography/39350.aspx#|archive-date=2013-10-15 October 2013|url-status=dead}}</ref>

Multi-mode passive detection systems (MMPDS), based upon [[muon tomography]], are currently in use by Decision Sciences International Corporation at Freeport, Bahamas,<ref>[http://www.decisionsciencescorp.com/cargo-security-international-dr-stanton-d-sloane-of-decision-sciences-looks-at-how-passive-detection-systems-can-play-their-part-in-protecting-the-global-supply-chain/ "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]</ref> and the [[Atomic Weapons Establishment]] in the [[United Kingdom]].<ref>[http://www.decisionsciencescorp.com/decision-sciences-awarded-atomic-weapons-establishment-awe-contract-for-nuclear-detection-system/ "Decision Sciences Awarded Atomic Weapons Establishment (AWE) Contract for Nuclear Detection System."]</ref> An MMPDS system has also been contracted by Toshiba in order to determine the location and the condition of the nuclear fuel in the [[Fukushima Daiichi Nuclear Power Plant]].<ref>[http://www.world-nuclear-news.org/RS-Cosmic-rays-to-pinpoint-Fukushima-cores-1108144.html "Cosmic Rays to pinpoint Fukushima cores" by World Nuclear News]</ref>

Radiological materials emit gamma photons, which [[gamma ray|gamma]] [[radiation detector]]s, also called radiation portal monitors (RPM), are good at detecting. Systems currently used in US ports (and [[steel mill]]s) use several (usually 4) large [[Polyvinyl toluene|PVT]] panels as [[scintillator]]s and can be used on vehicles moving up to 16&nbsp;km/h.<ref>{{cite web|title=Overview of Exploranium's AT-980 Radiation Portal Monitor (RPM) |url=http://www.saic.com/products/security/at-980/ |accessdate=Sep1 September 2007 |url-status=dead |archiveurl=https://web.archive.org/web/20071009061733/http://www.saic.com/products/security/at-980/ |archivedate=9 October 2007-10-09 }}</ref>

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, [[cat litter]], [[granite]], [[porcelain]], [[stoneware]], etc.<ref name=hor>{{cite book| title =Waste, Abuse, and Mismanagement in Department of Homeland Security Contracts| publisher =[[United States House of Representatives]]| date =July 2006| pages =12–13| url =http://oversight.house.gov/documents/20060727092939-29369.pdf| access-date =2007-09-10 September 2007| archive-url =https://web.archive.org/web/20070830000432/http://oversight.house.gov/documents/20060727092939-29369.pdf| archive-date =2007-08-30 August 2007| url-status =dead}}</ref> Those [[naturally occurring radioactive material]]s, called NORMs account for 99% of nuisance alarms.<ref>{{cite web| title = Manual for Ludlum Model 3500-1000 Radiation Detector System| url=http://www.ludlums.com/manuals/M3500-1000mar06.pdf| accessdate = Sep1 September 2007 }}</ref> Some radiation, like in the case of large loads of bananas is due to [[potassium]] and its rarely occurring (0.0117%) radioactive isotope potassium-40, other is due to [[radium]] or [[uranium]] that occur naturally in earth and rock, and cargo types made out of them, like cat litter or porcelain.

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<ref>{{cite news| last =Wald | first =M.| title =Shortage Slows a Program to Detect Nuclear Bombs| work =The New York Times| date =November 22, November 2009| url =https://www.nytimes.com/2009/11/23/us/23helium.html}}</ref> has led to the search for other technologies for neutron detection.