neutron radiation is difficult to detect
californium
(Cf), synthetic chemical element of the actinide series in Group IIIb of the periodic table, atomic number 98. Not occurring in nature, californium (as the isotope californium-245) was discovered (1950) by Stanley G. Thompson, Kenneth Street, Jr., Albert Ghiorso, and Glenn T. Seaborg at the University of California, Berkeley, as a product resulting from the helium-ion bombardment of curium-242 (atomic number 96) in the 60-inch cyclotron.
All californium isotopes are radioactive; the long-lived isotopes are produced from berkelium-249 or from californium-249. They are: californium-249 (360-year half-life); californium-250 (13-year half-life); californium-251 (800-year half-life); and californium-252 (2.65-year half-life). These isotopes have been used in tracer amounts for investigating the chemistry of californium (which exhibits an oxidation state of +3 in acidic aqueous solution) and for preparing microgram quantities of compounds such as the oxychloride CfOCl, the oxide Cf2O3, and the trichloride CfCl3. There is some evidence for a +2 state also.

>>>Metallic californium has not yet been prepared. (This is a lie OP)<<<<<

Californium-252, because 3 percent of its decay occurs by spontaneous fission,<<<<<<<<<<<<<<<< is industrially and medically important as a very intense point source of neutrons. One microgram releases 170,000,000 neutrons per minute.


atomic number 98
stablest isotope 251
valence 3
electronic config. 2-8-18-32-28-8-2 or (Rn)5f 107s2