Californium is a radioactive element with the symbol Cf and atomic number 98. It was first discovered in 1950 by scientists at the University of California, Berkeley. Californium is part of the actinide series and is known for its ability to emit neutrons, making it useful in various applications, including nuclear reactors and medical treatments. This element is produced in very small quantities through the bombardment of curium with neutrons. Californium is primarily used in neutron moisture gauges, neutron radiography, and as a neutron source in scientific research. Due to its radioactivity, it must be handled with care.