Californium
Isotopes

Twenty isotopes of californium are known (mass number ranging from 237 to 256); the most stable are Cf with half-life 898 years, Cf with half-life 351 years, Cf at 13.08 years, and Cf at 2.645 years. All other isotopes have half-life shorter than a year, and most of these have half-lives less than 20 minutes.

Cf is formed by beta decay of berkelium-249, and most other californium isotopes are made by subjecting berkelium to intense neutron radiation in a nuclear reactor. Though californium-251 has the longest half-life, its production yield is only 10% due to its tendency to collect neutrons (high neutron capture) and its tendency to interact with other particles (high neutron cross section).

Cf is a very strong neutron emitter, which makes it extremely radioactive and harmful. Cf, 96.9% of the time, alpha decays to curium -248; the other 3.1% of decays are spontaneous fission. One microgram (μg) of Cf emits 2.3 million neutrons per second, an average of 3.7 neutrons per spontaneous fission. Most other isotopes of californium, alpha decay to curium (atomic number 96).
language:response_language[German], startend:quotation