Cluster decay

From Wikipedia, the free encyclopedia

Nuclear processes
Radioactive decay processes Alpha decay Beta decay Cluster decay Double beta decay Double electron capture Electron capture Gamma radiation Internal conversion Isomeric transition Neutron emission Positron emission Proton emission Spontaneous fission Nucleosynthesis Nuclear fusion Proton-proton chain reaction CNO cycle Triple-alpha process Carbon burning process Neon burning process Oxygen burning process Silicon burning process Neutron capture The R-process The S-process Proton capture: The P-process The Rp-process Spallation

Cluster decay is the nuclear process in which a radioactive atom emits a cluster of neutrons and protons. While this term technically includes alpha decay, they are usually kept separate because the latter is much more common. Cluster decay occurs only a small percentage of the time in all cases. It also is limited to the heavy atoms which have the energy to expel a portion of its nucleus.

Cluster decay is notably different from spontaneous fission. In the event of spontaneous fission there will be many different species of daughter products. In cluster decay there is always the same particle emitted.

Tritons and deuterons are also known as radioactive decay products. Helium-6 occasionally decays via deuteron emission and Helium-8 decays a small part of the time with a triton emission. It is possible that other exotic isotopes decay in these methods as helium is studied in particle accelerators to a great degree.

The known cluster emissions are as follows:

Isotope	Particle emission	Decay percentage
114-Ba	12-C	3.0E-5 %
221-Fr	14-C	9E-13 %
221-Ra	14-C	1E-12 %
222-Ra	14-C	3.0E-8 %
223-Ra	14-C	8.9E-8 %
224-Ra	14-C	4.0E-9 %
226-Ra	14-C	3.2E-9 %
225-Ac	14-C	6E-10 %
228-Th	20-O	1E-11 %
232-Th	Ne	?
232-U	Ne	9E-10 %
233-U	Ne	7E-11 %
234-U	Mg Ne	1E-11 % 9E-12 %
235-U	Ne 28-Mg	8.E-10 % 8.E-10 %
236-U	30-Mg	?
242-Cm	34-Si	1.E-14 %