Californium

²⁵²Cf is a very active source of neutrons (2.3×10⁶ neutrons per second per microgram) with a half-life of 2.65 years. The energy spectrum of the neutrons is very similar to that of a fission reactor and small amounts of ²⁵²Cf provide an ideal portable source for low neutron flux applications [75], [625], [626]. ²⁵²Cf is used for PGNAA (prompt gamma neutron activation analysis, a method for detecting many chemical elements in samples simultaneously) in the analysis of coal, cement, minerals, weapon components, and chemical munitions [627]. This method provides a quick and non-destructive elemental analysis of a sample. For example, ²⁵²Cf, as the neutron source for PGNAA, is used to detect the presence of antitank mines [625]. Neutron activation analysis (NAA) uses ²⁵²Cf as a portable neutron source to bombard a small sample from the area of interest with neutrons and analyze the radioactive emissions from that bombardment to help identify silver or gold ore [75]. ²⁵²Cf has been used in neutron moisture gauges to locate water [628]. ²⁵²Cf is used in borehole geophysical logging for subsurface PGNAA investigation of waste (Fig. IUPAC.98.1) [629]. Formation fluid identification uses ²⁵²Cf as a chemical neutron source for elastic/inelastic neutron backscattering and/or neutron activation methods in well-logging to determine water- and oil-bearing layers and other downhole properties of the well bore [629].

²⁵²Cf is sometimes used in boron neutron capture therapy (BNCT) as a source of neutrons that can be delivered close to the region of a tumor [75], [625], [626]. Brachytherapy can use ²⁵²Cf to treat many types of cancer [75], [625], [626].