Double beta decay
From Biocrawler, the free encyclopedia.
| Nuclear processes |
Radioactive decay processes
|
In the process of beta decay unstable nuclei decay by converting a neutron in the nucleus to a proton and emitting an electron and anti-neutrino. In order for beta decay to be possible the final nucleus must have a larger binding energy than the original nucleus. For some nuclei, such as Germanium-76 the nuclei with atomic number one higher has a smaller binding energy, preventing beta decay from occurring. In the case of Germanium-76 the nuclei with atomic number two higher, Selenium-76 has a larger binding energy, so the "double beta decay" process is allowed.
In double beta decay two neutrons in the nuclei are converted to protons, and two electrons and two anti-neutrinos are emitted. This process was first observed in 1986.
Neutrinoless double beta decay
The process described above is also known as two neutrino double beta decay, as two neutrinos are emitted. If the neutrino is a Majorana particle, meaning that the anti-neutrino and the neutrino are actually the same particle then it is possible for neutrinoless double beta decay to occur. In neutrinoless double beta decay the two neutrinos annihilate very quickly after they are produced, so the total kinetic energy of the two electrons would be exactly the difference in binding energy between the initial and final state nuclei. Several experiments have been proposed to search for neutrinoless double beta decay, as its discovery would indicate that neutrinos are indeed Majorana particles and allow a calculation of their mass.
