Editing Californium (section)

== Applications ==
[[File:CfShield.JPG|thumb|Fifty-ton shipping cask built at ORNL which can transport up to 1 gram of {{sup|252}}Cf.{{sfn|Seaborg|1994|p=245}} Large and heavily shielded transport containers are needed to prevent the release of highly radioactive material in case of normal and hypothetical accidents.<ref>{{cite web|url=http://rampac.energy.gov/PCN/EM-PCP-certified-pkgs-8808.pdf|title=DOE Certified Radioactive Materials Transportation Packagings|last=Shuler|first=James|date=2008|page=1|publisher=United States Department of Energy|access-date=April 7, 2011|archive-date=October 15, 2011|archive-url=https://web.archive.org/web/20111015040627/http://rampac.energy.gov/PCN/EM-PCP-certified-pkgs-8808.pdf|url-status=dead}}</ref>|alt= Large conical structure on a pulley with a man on top and two near the base.]]

<!-- NEEDS CITE Californium is the heaviest metal known at this time that has a practical use outside of research laboratories; [[einsteinium]] and all other elements above it have sufficiently short half-lives that they have no use except the production of heavier elements.-->=== Neutron source ===
{{SimpleNuclide|Californium|252|link=yes}} has a number of specialized uses as a strong [[Neutron source|neutron emitter]]; it produces 139&nbsp;million neutrons per microgram per minute.<ref name="osti" /> This property makes it useful as a [[startup neutron source]] for some nuclear reactors{{sfn|O'Neil|2006|p=276}} and as a portable (non-reactor based) neutron source for [[neutron activation analysis]] to detect trace amounts of elements in samples.<ref name="Martin2000">{{cite conference|last=Martin |first=R. C. |title=Applications and Availability of Californium-252 Neutron Sources for Waste Characterization |date=September 24, 2000 |url=http://www.ornl.gov/~webworks/cpr/pres/107270_.pdf |access-date=May 2, 2010 |conference=Spectrum 2000 International Conference on Nuclear and Hazardous Waste Management |location=Chattanooga, Tennessee |url-status=dead |archive-url=https://web.archive.org/web/20100601160926/http://www.ornl.gov/~webworks/cpr/pres/107270_.pdf |archive-date=June 1, 2010 }}</ref>{{efn|By 1990, californium-252 had replaced plutonium-[[beryllium]] neutron sources due to its smaller size and lower heat and gas generation.{{sfn|Seaborg|1990|p=318}} }} Neutrons from californium are used as a treatment of certain [[Cervical cancer|cervical]] and [[brain tumor|brain cancers]] where other [[radiation therapy]] is ineffective.{{sfn|O'Neil|2006|p=276}} It has been used in educational applications since 1969 when [[Georgia Tech|Georgia Institute of Technology]] got a loan of 119&nbsp;μg of {{sup|252}}Cf from the [[Savannah River Site]].{{sfn|Osborne-Lee|1995|p=33}} It is also used with online elemental [[coal analyzer]]s and [[bulk material analyzer]]s in the coal and cement industries.

Neutron penetration into materials makes californium useful in detection instruments such as [[fuel rod]] scanners;{{sfn|O'Neil|2006|p=276}} [[Neutron imaging#Neutron radiography (film)|neutron radiography]] of aircraft and weapons components to detect [[corrosion]], bad welds, cracks and trapped moisture;{{sfn|Osborne-Lee|1995|pp=26–27}}<!-- NEEDS CITE in airport [[prompt gamma neutron activation analysis|neutron-activation]] detectors of explosives, --> and in portable metal detectors.<ref>{{cite web|url=http://www.pnl.gov/news/2000/00-43.htm|title=Will You be 'Mine'? Physics Key to Detection|date=October 25, 2000|publisher = Pacific Northwest National Laboratory|access-date = March 21, 2007 |archive-url = https://web.archive.org/web/20070218125029/http://www.pnl.gov/news/2000/00-43.htm <!-- Bot retrieved archive --> |archive-date = February 18, 2007 }}</ref> [[Neutron moisture gauge]]s use {{sup|252}}Cf to find water and petroleum layers in oil wells, as a portable [[neutron source]] for gold and silver prospecting for on-the-spot analysis,{{sfn|CRC|2006|p=4.8}} and to detect ground water movement.<ref>{{cite journal|journal = Ground Water|volume = 18|issue = 1|pages =14–23|date = 2006|title =Ground-Water Tracers – A Short Review|author = Davis, S. N. |doi = 10.1111/j.1745-6584.1980.tb03366.x|last2 = Thompson|first2 = Glenn M.|last3 = Bentley|first3 = Harold W.|last4 = Stiles|first4 = Gary }}</ref> The main uses of {{sup|252}}Cf in 1982 were, reactor start-up (48.3%), fuel rod scanning (25.3%), and activation analysis (19.4%).{{sfn|Osborne-Lee|1995|p=12}} By 1994, most {{sup|252}}Cf was used in neutron radiography (77.4%), with fuel rod scanning (12.1%) and reactor start-up (6.9%) as important but secondary uses.{{sfn|Osborne-Lee|1995|p=12}} In 2021, fast neutrons from {{sup|252}}Cf were used for wireless data transmission.<ref>{{cite journal|journal = Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment|volume = 1021|issue = 1|pages = 165946|date = 2022|title = Wireless information transfer with fast neutrons|author = Joyce, Malcolm J.|last2 = Aspinall|first2 = Michael D.|last3 = Clark|first3 = Mackenzie|last4 = Dale|first4 = Edward|last5 = Nye|first5 = Hamish|last6 = Parker|first6 = Andrew|last7 = Snoj|first7 = Luka|last8 = Spires|first8 = Joe|doi = 10.1016/j.nima.2021.165946| bibcode=2022NIMPA102165946J | s2cid=240341300 |issn=0168-9002 |doi-access = free}}</ref>

=== Superheavy element production ===
{{See also|Superheavy element#Synthesis of superheavy nuclei}}
In October 2006, researchers announced that three atoms of [[oganesson]] (element 118) had been identified at [[Joint Institute for Nuclear Research]] in [[Dubna]], [[Russia]], from bombarding {{sup|249}}Cf with [[calcium-48]], making it the heaviest element ever made. The target contained about 10&nbsp;mg of {{sup|249}}Cf deposited on a titanium foil of 32&nbsp;cm{{sup|2}} area.<ref>{{cite journal |title = Synthesis of the isotopes of elements 118 and 116 in the californium-249 and <sup>245</sup>Cm+<sup>48</sup>Ca fusion reactions |journal = Physical Review C |date = 2006 |volume = 74 |issue =4 |pages = 044602–044611 |doi = 10.1103/PhysRevC.74.044602 |bibcode=2006PhRvC..74d4602O |last1=Oganessian |first1=Yu. Ts. |last2=Utyonkov |first2=V. |last3=Lobanov |first3=Yu. |last4=Abdullin |first4=F. |last5=Polyakov |first5=A. |last6=Sagaidak |first6=R. |last7=Shirokovsky |first7=I. |last8=Tsyganov |first8=Yu. |last9=Voinov |first9=A. |display-authors=8 |doi-access=free}}</ref><ref>{{cite journal |author = Sanderson, K. |title = Heaviest element made – again |journal = Nature News |publisher =Nature |date = October 17, 2006 |doi=10.1038/news061016-4 |s2cid = 121148847}}</ref><ref>{{cite web|author=Schewe, P. |author2=Stein, B. |title=Elements 116 and 118 Are Discovered |work=Physics News Update |publisher=American Institute of Physics |date=October 17, 2006 |url=http://www.aip.org/pnu/2006/797.html |access-date=October 19, 2006 |url-status=dead |archive-url=https://web.archive.org/web/20061026072537/http://www.aip.org/pnu/2006/797.html |archive-date=October 26, 2006 }}</ref> <!-- EXPLAIN Calibration, [[dosimetry]], and fission fragment and half-life studies are other applications of californium.{{sfn|Osborne-Lee|1995|p=34}} --> Californium has also been used to produce other transuranic elements; for example, [[lawrencium]] was first synthesized in 1961 by bombarding californium with [[boron]] nuclei.<ref>{{cite journal|title = Element 103 Synthesized|journal = Science News-Letter|volume = 79|issue = 17|date=April 1961|page = 259|doi = 10.2307/3943043|author1 = <Please add first missing authors to populate metadata.> |jstor = 3943043}}</ref>

=== Hypothetical nuclear weapons ===
{{See also|Nuclear weapon design#Minor actinide fission weapons}}
{{SimpleNuclide|Californium|251|link=yes}} has a very small calculated [[critical mass]] of about {{convert|5|kg|0|abbr=on}},<ref>{{cite web |title=Evaluation of nuclear criticality safety data and limits for actinides in transport |url=http://ec.europa.eu/energy/nuclear/transport/doc/irsn_sect03_146.pdf |url-status=dead |archive-url=https://web.archive.org/web/20110519171204/http://ec.europa.eu/energy/nuclear/transport/doc/irsn_sect03_146.pdf |archive-date=May 19, 2011 |access-date=December 20, 2010 |publisher=Institut de Radioprotection et de Sûreté Nucléaire |page=16}}</ref> high lethality, and a relatively short period of toxic environmental irradiation. The low critical mass of californium led to some exaggerated claims about possible uses for the element.{{efn|An article entitled "Facts and Fallacies of World War III" in the July 1961 edition of ''[[Popular Science]]'' magazine read "A californium atomic bomb need be no bigger than a pistol bullet. You could build a hand-held six-shooter to fire bullets that would explode on contact with the force of 10 tons of TNT."<ref>{{cite journal|journal=[[Popular Science]]|pages= 92–95, 178–181|date=July 1961|volume=179|issue=1|issn=0161-7370|title=Facts and Fallacies of World War III|url=https://books.google.com/books?id=OiEDAAAAMBAJ&pg=PA180|author1=Mann, Martin}}"force of 10 tons of TNT" on page 180.</ref>}}