Editing Tritium (section)

=== Cosmic rays ===
Tritium occurs naturally due to [[cosmic ray]]s interacting with atmospheric gases. In the most important reaction for natural production, a [[Neutron temperature#Fast|fast neutron]] (which must have energy greater than 4.0&nbsp;[[Electronvolt|MeV]]<ref>
{{cite web
 | last1 = Young  | first1 = P.G.
 | last2 = Foster | first2 = D.G. Jr.
 | date = September 1972
 | name-list-style = amp
 | title = An evaluation of the neutron and gamma-ray production cross-sections for nitrogen
 | publisher = [[Los Alamos Scientific Laboratory]]
 | place =  [[Los Alamos, NM]]
 | url = https://fas.org/sgp/othergov/doe/lanl/lib-www/la-pubs/00320217.pdf
 | access-date= 19 September 2010
}}
</ref>) interacts with atmospheric [[nitrogen]]:
: {{nuclide|link=yes|nitrogen|14}} + n → {{nuclide|link=yes|carbon|12}} + {{nuclide|hydrogen|3}}

Worldwide, the production of tritium from natural sources is 148&nbsp;peta[[becquerel]]s per year. The global equilibrium inventory of tritium created by natural sources remains approximately constant at 2,590&nbsp;petabecquerels. This is due to a fixed production rate, and losses proportional to the inventory.<ref name=physics.isu.edu-RIN-Tritium>
{{cite web
 |title=Tritium information section
 |series=Radiation Information Network 
 |department=Physics Department
 |publisher=Idaho State University
 |url=http://www.physics.isu.edu/radinf/tritium.htm
 |archive-url=https://web.archive.org/web/20160303184224/http://www.physics.isu.edu/radinf/tritium.htm
 |archive-date=3 March 2016
}}</ref>