Editing Californium (section)

== Production ==
{{see also|Nuclear fuel cycle}}
Californium is produced in [[nuclear reactor]]s and [[particle accelerator]]s.{{sfn|Krebs|2006|pp=327–328}} Californium-250 is made by bombarding berkelium-249 ({{sup|249}}Bk) with neutrons, forming berkelium-250 ({{sup|250}}Bk) via [[neutron capture]] (n,γ) which, in turn, quickly [[beta decay]]s (β{{sup|−}}) to californium-250 ({{sup|250}}Cf) in the following reaction:{{sfn|Heiserman|1992|p=348}}
:{{nuclide|Bk|249}}(n,γ){{nuclide|Bk|250}} → {{nuclide|Cf|250}} + β{{sup|−}}
Bombardment of {{sup|250}}Cf with neutrons produces {{sup|251}}Cf and {{sup|252}}Cf.{{sfn|Heiserman|1992|p=348}}

Prolonged irradiation of [[americium]], curium, and plutonium with neutrons produces milligram amounts of {{sup|252}}Cf and microgram amounts of {{sup|249}}Cf.{{sfn|Cunningham|1968|p=105}} As of 2006, curium isotopes 244 to 248 are irradiated by neutrons in special reactors to produce mainly californium-252 with lesser amounts of isotopes 249 to 255.{{sfn|Haire|2006|p=1503}}

Microgram quantities of {{sup|252}}Cf are available for commercial use through the U.S. [[Nuclear Regulatory Commission]].{{sfn|Krebs|2006|pp=327–328}} Only two sites produce {{sup|252}}Cf: Oak Ridge National Laboratory in the U.S., and the [[Research Institute of Atomic Reactors]] in [[Dimitrovgrad, Russia]]. As of 2003, the two sites produce 0.25 grams and 0.025 grams of {{sup|252}}Cf per year, respectively.{{sfn|NRC|2008|p=33}}

Three californium isotopes with significant half-lives are produced, requiring a total of 15 neutron captures by [[uranium-238]] without [[nuclear fission]] or alpha decay occurring during the process.{{sfn|NRC|2008|p=33}} {{sup|253}}Cf is at the end of a production chain that starts with uranium-238, and includes several [[isotopes of plutonium]], [[isotopes of americium|americium]], [[isotopes of curium|curium]],  and [[isotopes of berkelium|berkelium]], and the californium isotopes 249 to 253 (see diagram).
{{Clear}}
[[File:Cf 252 Produktion.png|center|upright=2.8|thumb|Scheme of the production of californium-252 from uranium-238 by neutron irradiation|alt=A complex flow diagram showing various isotopes.]]