Californium is a radioactive element with the symbol Cf and atomic number 98. It was discovered in 1950 by scientists at the University of California, Berkeley, and is named after the state of California. Californium is part of the actinide series and is produced in nuclear reactors. This element is primarily used in neutron activation analysis and as a neutron source in various applications, including nuclear reactors and medical treatments. Due to its radioactivity, californium must be handled with care, and its use is limited to specialized fields.