Radioactive decay

Radioactive decay is the process by which radionuclides decay, emitting ionising radiation[?].

The observed forms of decay are alpha decay, beta decay, neutron emission[?], proton emission[?], and spontaneous fission[?]. The latter three forms of decay occur very quickly within products of nuclear reactions, and hence are not often seen on earth outside a nuclear reactor. By contrast alpha and beta decay are seen in the decay chains of radioactive materials.

Neutron emission is also important as the most important reason for the difficulty of manufacturing a nuclear bomb from lower grades of plutonium.

Radioactive decay is observed astronomically in supernova, and the light curve of supernova is generated via the decay of radioactive nickel into iron.

Many radionuclides have several different modes of decay, each with its own probability. Bismuth-212, for example, has three.

All radioactive decay is also associated with emission of gamma radiation in varying degrees.

Nearly all decay products are themselves radioactive, giving rise to decay chains which eventually end in a stable nuclide.

External Links

• Decay chains (http://www.epa.gov/radiation/understand/chain.htm)
• Uranium-238 decay chain (http://www.atral.com/U2381.html)
• Sulphur-38 decay chain (http://www.ag.ohio-state.edu/~rer/rerhtml/rer_20.html)
• List of decay modes (http://www.nuclides.net/Applets/about_radioactive_decay.htm)
• More examples (http://www.public.iastate.edu/~chemistry/Courses/chem178/apr23.html)
• Uranium-232 decay chain, Bismuth-212 decay modes (http://www.nuclides.net/Nuclides_2000/U-232.htm)
• Radiochemistry Primer (http://www.cmc.sandia.gov/Central/public-docs/APrimeronRadiochemistry1.htm)
• Nuclear stability (http://www2.slac.stanford.edu/vvc/theory/nuclearstability.html)