Editing Muon (section)

== Muon radiography and tomography ==
{{main|Muon tomography}}

Since muons are much more deeply penetrating than [[X-ray]]s or [[gamma ray]]s, muon imaging can be used with much thicker material or, with cosmic ray sources, larger objects. One example is commercial muon tomography used to image entire cargo containers to detect shielded [[nuclear material]], as well as explosives or other contraband.<ref>{{cite web |title=Decision Sciences Corp |url=http://www.decisionsciencescorp.com/solutions/mmpds/ |access-date=10 February 2015 |archive-date=19 October 2014 |archive-url=https://web.archive.org/web/20141019081554/http://www.decisionsciencescorp.com/solutions/mmpds/ |url-status=dead }}{{failed verification|date=October 2019}}</ref>

The technique of muon transmission radiography based on cosmic ray sources was first used in the 1950s to measure the depth of the [[overburden]] of a tunnel in Australia<ref>{{cite journal |last=George |first=E.P. |title=Cosmic rays measure overburden of tunnel |journal=Commonwealth Engineer |date=1 July 1955 |page=455}}</ref> and in the 1960s to search for possible hidden chambers in the [[Pyramid of Khafre|Pyramid of Chephren]] in [[Giza]].<ref>{{cite journal |last=Alvarez |first=L.W. |title=Search for hidden chambers in the pyramids using cosmic rays |journal=Science |year=1970 |volume=167 |issue=3919 |pages=832–839 |doi=10.1126/science.167.3919.832 |pmid=17742609 |bibcode=1970Sci...167..832A }}</ref> In 2017, the discovery of a large void (with a length of 30 metres minimum) by observation of cosmic-ray muons was reported.<ref name="Discovery of a big void in Khufu's Pyramid by observation of cosmic-ray muons">{{cite journal |title=Discovery of a big void in Khufu's Pyramid by observation of cosmic-ray muons |journal=Nature |volume= 552|issue= 7685|pages=386–390 |year= 2017|last1=Morishima |first1=Kunihiro |last2=Kuno |first2=Mitsuaki |last3=Nishio |first3=Akira |last4=Kitagawa |first4=Nobuko |last5=Manabe |first5=Yuta |bibcode=2017Natur.552..386M |arxiv=1711.01576 |doi=10.1038/nature24647 |pmid=29160306|s2cid=4459597 }}</ref>

In 2003, the scientists at [[Los Alamos National Laboratory]] developed a new imaging technique: ''muon scattering tomography''. With muon scattering tomography, both incoming and outgoing trajectories for each particle are reconstructed, such as with sealed aluminum [[Wire chamber|drift tubes]].<ref name="Radiographic imaging with cosmic-ray muons">{{cite journal |doi=10.1038/422277a |pmid=12646911 |title=Radiographic imaging with cosmic-ray muons |journal=Nature |volume=422 |issue=6929 |page=277 |year=2003 |last1=Borozdin |first1=Konstantin N. |last2=Hogan |first2=Gary E. |last3=Morris |first3=Christopher |last4=Priedhorsky |first4=William C. |last5=Saunders |first5=Alexander |last6=Schultz |first6=Larry J. |last7=Teasdale |first7=Margaret E. |bibcode=2003Natur.422..277B|s2cid=47248176 |doi-access=free }}</ref> Since the development of this technique, several companies have started to use it.

In August&nbsp;2014, Decision Sciences International Corporation announced it had been awarded a contract by [[Toshiba]] for use of its muon tracking detectors in reclaiming the [[Fukushima Daiichi Nuclear Power Plant|Fukushima nuclear complex]].<ref>{{cite press release |url=http://www.decisionsciencescorp.com/ds-awarded-toshiba-contract-fukushima-daiichi-nuclear-project/ |title=Decision Sciences awarded Toshiba contract for Fukushima Daiichi Nuclear Complex project |publisher=Decision Sciences |date=8 August 2014 |access-date=10 February 2015 |archive-date=10 February 2015 |archive-url=https://web.archive.org/web/20150210235248/http://www.decisionsciencescorp.com/ds-awarded-toshiba-contract-fukushima-daiichi-nuclear-project/ |url-status=dead }}</ref> The Fukushima Daiichi Tracker was proposed to make a few months of muon measurements to show the distribution of the reactor cores. In December&nbsp;2014, [[Tokyo Electric Power Company|Tepco]] reported that they would be using two different muon imaging techniques at Fukushima, "muon scanning method" on Unit&nbsp;1 (the most badly damaged, where the fuel may have left the reactor vessel) and "muon scattering method" on Unit&nbsp;2.<ref>{{cite web |url=http://fukushima-diary.com/2015/01/tepco-start-scanning-inside-reactor-1-early-february-using-muon/ |title=Tepco to start "scanning" inside of Reactor&nbsp;1 in early February by using muons |website=Fukushima Diary |date=January 2015}}</ref> The International Research Institute for Nuclear Decommissioning [[IRID]] in Japan and the High Energy Accelerator Research Organization [[KEK]] call the method they developed for Unit&nbsp;1 the "muon permeation method"; 1,200&nbsp;optical fibers for wavelength conversion light up when muons come into contact with them.<ref>{{cite web |url=http://irid.or.jp/en/topics/%E3%80%8C%E3%83%9F%E3%83%A5%E3%82%AA%E3%83%B3%E9%80%8F%E9%81%8E%E6%B3%95%E3%80%8D%E6%B8%AC%E5%AE%9A%E5%99%A8%E3%81%AE%E8%A3%BD%E4%BD%9C%E3%81%AA%E3%82%89%E3%81%B3%E3%81%AB%E6%B5%B7%E5%A4%96%E3%83%AC/ |title=Muon measuring instrument production for "muon permeation method" and its review by international experts |website=IRID.or.jp}}</ref> After a month of data collection, it is hoped to reveal the location and amount of fuel debris still inside the reactor. The measurements began in February 2015.<ref>{{cite web |url=http://www.fukuleaks.org/web/?p=14380 |title=Muon scans begin at Fukushima Daiichi |website=SimplyInfo |date=3 February 2015 |access-date=7 February 2015 |archive-date=7 February 2015 |archive-url=https://web.archive.org/web/20150207105206/http://www.fukuleaks.org/web/?p=14380 |url-status=dead }}</ref>