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Californium-249

Main isotopes of californium
iso NA half-life DM DE (MeV) DP
248Cf syn 333.5 d α (100%) 6.369 244Cm
SF (2.9×10−3%) 0.0029
249Cf syn 351 y α (100%) 6.295 245Cm
SF (5.0×10−7%) 4.4×10−7
250Cf syn 13.08 y α (99.92%) 6.129 246Cm
SF (0.08%) 0.077
251Cf syn 898 y α 6.172 247Cm
252Cf syn 2.645 y α (96.91%) 6.217 248Cm
SF (3.09%)
253Cf syn 17.81 d β (99.69%) 0.29 253Es
α (0.31%) 6.126 249Cm
254Cf syn 60.5 d SF (99.69%)
α (0.31%) 5.930 250Cm

Californium (98Cf) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 245Cf in 1950. There are 20 known radioisotopes ranging from 237Cf to 256Cf and one nuclear isomer, 249mCf. The longest-lived isotope is 251Cf with a half-life of 900 years.

No fission products
have a half-life
in the range of
100–210 k years ...

... nor beyond 15.7 M years

Legend for superscript symbols
₡  has thermal neutron capture cross section in the range of 8–50 barns
ƒ  fissile
metastable isomer
№  naturally occurring radioactive material (NORM)
þ  neutron poison (thermal neutron capture cross section greater than 3k barns)
†  range 4–97 y: Medium-lived fission product
‡  over 200,000 y: Long-lived fission product

Californium-252 (Cf-252) undergoes spontaneous fission and is used in small sized neutron sources. Fission neutrons have an energy range of 0 to 13 MeV with a mean value of 2.3 MeV and a most probable value of 1 MeV.

This isotope produces high neutron emissions and can be used for a number of applications in industries such as nuclear energy, medicine, and petrochemical exploration.


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