Explosive detection: Difference between revisions

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{{Short description|Non-destructive inspection process}}

[[Image:Explosive detection dog, CBP.jpg|right|thumb|An [[U.S. Customs and Border Protection]] officer with an explosive-detection dog]]

'''Explosive detection''' is a non-destructive [[inspection]] process to determine whether a container contains [[explosive material]]. Explosive detection is commonly used at [[airport]]s, [[port]]s and for [[border control]]. Regardless of the specific tools, the technologies can be classified into four main types: imaging technologies (mainly X-rays), EDDs (Explosive Detection Dogs), ETDs (Explosive Trace Detectors), and EVDs (Explosive Vapor Detectors).

==Types of Detection techniques==

===Imaging (main X-rays)===

The use of colorimetric test kits for explosive detection is one of the most established, simplest, and most widely used methods for the detection of explosives. Colorimetric detection of explosives involves applying a chemical reagent to an unknown material or sample and observing a color reaction. Common color reactions are known and indicate to the user if there is an explosive material present and in many cases the group of explosives from which the material is derived. The major groups of explosives are [[Nitroaromatic compound|nitroaromatic]], [[nitrate ester]], and [[Nitroamine|nitramine]] explosives, as well as inorganic nitrate-based explosives. Other groups include [[chlorate]]s and [[peroxide]]s which are not nitro based explosives. Since explosives usually contain nitrogen, detection often is based around spotting nitrogenous compounds. As a result, traditional colorimetric tests have a disadvantage: some explosive compounds (such as [[acetone peroxide]]) do not contain nitrogen and are therefore harder to detect.<ref>{{Cite book |last1=Marshall |first1=Maurice |url=https://www.worldcat.org/oclc/316212529 |title=Aspects of explosives detection |last2=Oxley |first2=Jimmie |date=2009 |publisher=[[Elsevier]] |isbn=978-0-08-092314-7 |edition=1st |___location=Amsterdam |doi=10.1016/B978-0-12-374533-0.X0001-3 |oclc=316212529}}</ref>

==Detection tools==

===Colorimetrics & automated colorimetrics===

The use of [[colorimetric]] test kits for explosive detection is one of the most established,simple methods for simplestofficers, and most widely used methodsmethod for the detection of explosives. Colorimetric detection of explosives involves applying a chemical reagent to an unknown material or sample and observing a [[color reaction]]. Common color reactions are known and indicate to the user if there is an explosive material present and in many cases the group of explosives from which the material is derived. The major groups of explosives are [[Nitroaromatic compound|nitroaromatic]], [[nitrate ester]], and [[Nitroamine|nitramine]] explosives, as well as inorganic nitrate-based explosives. Other groups include [[chlorate]]s and [[peroxide]]s which are not nitro based explosives. Since explosives usually contain nitrogen, detection often is based around spotting nitrogenous compounds. As a result, traditional colorimetric tests have a disadvantage: some explosive compounds (such as [[acetone peroxide]]) do not contain nitrogen and are therefore harder to detect.<ref>{{Cite book |last1=Marshall |first1=Maurice |url=https://www.worldcat.org/oclc/316212529 |title=Aspects of explosives detection |last2=Oxley |first2=Jimmie |date=2009 |publisher=[[Elsevier]] |isbn=978-0-08-092314-7 |edition=1st |___location=Amsterdam |doi=10.1016/B978-0-12-374533-0.X0001-3 |oclc=316212529}}</ref>

===Dogs===

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These dogs are trained by specially trained handlers to identify the scents of several common explosive materials and notify their handler when they detect one of these scents. The dogs indicate a 'hit' by taking an action they are trained to provide ⁠— ⁠generally a passive response, such as sitting down and waiting.

The explosive detection canine was originated at the [[Metropolitan Police Department of the District of Columbia|Metropolitan Police Department]] in Washington, D.C. in 1970, by then trainer Charles R. Kirchner.<ref>{{Cite book |last=Newlon |first=Clarke |url=https://www.worldcat.org/oclc/881180 |title=Police Dogs in Action |date=1974 |publisher=[[Dodd, Mead & Co.]] |isbn=9780396069126 |___location=New York |oclc=881180}}</ref>

The explosive detection canine was first used in Algeria in 1959 under the command of [[General Constantine]].<ref>{{Citation |last1=Grandjean |first1=Dominique |title=Practical Guide for Sporting and Working Dogs |date=2000 |url=https://www.worldcat.org/oclc/1052842687 |page=4 |publisher=[[Royal Canin]] |isbn=2-914193-02-5 |oclc=1052842687 |access-date=2022-09-20 |last2=Moquet |first2=Nathalie |last3=Pawlowiez |first3=Sandrine |last4=Tourtebatte |first4=Anne-Karen |last5=Jean |first5=Boris |last6=Bacqué |first6=Hélenè}}.</ref>

Recent studies suggest that [[Mass spectrometry|mass spectrometric]] [[Explosive vapor detector|vapor analysis techniques]], such as [[secondary electrospray ionization]] (SESI-MS), could support canine training for explosive detection.<ref>{{Cite journal|last1=Ong|first1=Ta-Hsuan|last2=Mendum|first2=Ted|last3=Geurtsen|first3=Geoff|last4=Kelley|first4=Jude|last5=Ostrinskaya|first5=Alla|last6=Kunz|first6=Roderick|date=2017-06-09|title=Use of Mass Spectrometric Vapor Analysis To Improve Canine Explosive Detection Efficiency|journal=[[Analytical Chemistry (journal)|Analytical Chemistry]]|volume=89|issue=12|pages=6482–6490|doi=10.1021/acs.analchem.7b00451|pmid=28598144|issn=0003-2700}}</ref>

===Honey bees===

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One technique compares reflected [[ultraviolet]], [[infrared]] and [[visible light]] measurements on multiple areas of the suspect material. This has an advantage over olfactory methods in that a sample does not need to be prepared. A patent exists for a portable explosive detector using this method.<ref>{{Cite web |last=Mullins |first=Justin |date=2008-05-28 |title=Portable explosives detector |url=https://www.newscientist.com/blog/invention/2008/05/portable-explosives-detector.html |archive-url=https://web.archive.org/web/20080911045557/https://www.newscientist.com/blog/invention/2008/05/portable-explosives-detector.html |archive-date=11 September 2008 |website=[[New Scientist]] Blogs}}</ref>

Mass spectrometry is seen as the most relevant new spectrometry technique.<ref>{{Citation | url = http://www.nap.edu/catalog/10996.html | title = Opportunities to Improve Airport Passenger Screening with Mass Spectrometry | publisher = [[National Academies Press]] | doi = 10.17226/10996 | isbn = 978-0-309-09240-1 | year = 2004 }}.</ref> Several manufacturers have products that are under development, both in the US, Europe and Israel,<ref>{{cite web | publisher = Laser detect |url= http://www.laser-detect.com/brochures/LUMIN9689_narrowgate.pdf |title= Lumin 9689 Narrow gate |access-date=2012-04-11 |url-status= deadsubscription | type = brochure | format = [[Portable document format|PDF]] |archive-url= https://web.archive.org/web/20120823083344/http://www.laser-detect.com/brochures/LUMIN9689_narrowgate.pdf |archive-date= 2012-08-23}}.</ref> including Laser-Detect in Israel, [[Teledyne FLIR|FLIR Systems]] and Syagen in the US.

===X-ray machines===

Specially designed [[X-ray machine]]s using [[computed axial tomography]] can detect explosives by looking at the density of the items.. These systems that are furnished with dedicated software, containing an explosives threat library and [[false-color]] coding to assist operators with their dedicated threat resolution protocols.<ref>{{Cite journal |last1=Wells |first1=K. |last2=Bradley |first2=D.A. |date=2012 |title=A review of X-ray explosives detection techniques for checked baggage |url=http://dx.doi.org/10.1016/j.apradiso.2012.01.011 |journal=Applied Radiation and Isotopes |volume=70 |issue=8 |pages=1729–1746 |doi=10.1016/j.apradiso.2012.01.011 |pmid=22608981 |issn=0969-8043|url-access=subscription }}</ref> X-ray detection is also used to detect related components such as [[detonator]]s, but this can be foiled if such devices are hidden inside other electronic equipment.<ref>{{cite magazine |url= https://www.newscientist.com/channel/tech/weapons/dn9715|title=Analysis: Explosive detection technologies| first =Will | last = Knight|date=10 August 2006 |magazine=[[New Scientist]] news service |archive-url=https://web.archive.org/web/20220920215223/https://www.newscientist.com/article/dn9715-analysis-explosive-detection-technologies/ |archive-date=20 September 2022}}</ref>

Adding [[chemical marker|marker]] substances (X-ray opacifiers) to commercial explosives is also an option.<ref>National Academies of Sciences, Engineering, and Medicine. 1998. Containing the Threat from Illegal Bombings: An Integrated National Strategy for Marking, Tagging, Rendering Inert, and Licensing Explosives and Their Precursors. Washington, DC: The National Academies Press. [[doi:10.17226/5966]].</ref>

Recently, [[machine learning]] algorithms have been developed that can automatically detect threats in x-ray scans.<ref>{{Cite book|last1=Heitz|first1=Geremy|last2=Chechik|first2=Gal|title=2010 IEEE Computer Society Conference on Computer Vision and Pattern Recognition |chapter=Object separation in x-ray image sets |date=2010|pages=2093–2100|publisher=[[IEEE]] |doi=10.1109/cvpr.2010.5539887|isbn=978-1-4244-6984-0|s2cid=2643208}}</ref><ref>{{Citation|last=Mery|first=Domingo|title=Simulation in X-ray Testing|date=2015|work=Computer Vision for X-Ray Testing|pages=241–266|place=Cham|publisher=[[Springer International Publishing]] |doi=10.1007/978-3-319-20747-6_7|isbn=978-3-319-20746-9|s2cid=60787163 }}</ref><ref>{{Cite book|last1=Akcay|first1=Samet|last2=Breckon|first2=Toby P.|title=2017 IEEE International Conference on Image Processing (ICIP) |chapter=An evaluation of region based object detection strategies within X-ray baggage security imagery |publisher=[[IEEE]]|date=2017|pages=1337–1341|doi=10.1109/icip.2017.8296499|isbn=978-1-5090-2175-8|s2cid=3451234}}</ref>

===Neutron activation===