Isotopes of californium Isotopes of californium Californium (Cf) 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 Cf in 1950. There are 20 known radioisotopes ranging from Cf to Cf and one nuclear isomer, Cf. The longest-lived isotope is Cf with a half-life of 900 years. 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
Californium 9, 1950. It was the sixth transuranium element to be discovered; the team announced its discovery on March 17, 1950. To produce californium, a microgram-sized target of curium-242 () was bombarded with 35 MeV-alpha particles () in the cyclotron at Berkeley, which produced californium-245 () plus one free neutron (). Only about 5,000 atoms of californium were produced in this experiment, and these atoms had a half-life of 44 minutes. The discoverers named the new element after the university and the state. This was a break from the convention used for elements 95 to 97, which drew inspiration from how