Neutron emission

Neutron emission is a rarely occurring form of radioactivity in which a radioactive atomic nucleus decays by emitting a neutron. One example is 5He, an isotope of helium:

5He → 4He 1n

Only isotopes with significant surplus of neutrons decay by neutron emission. These are artificially generated for the most part, for example by spallation or induced nuclear fission. Naturally occurring radioactive isotopes decay usually by alpha, beta or gamma decay. Only in the case of spontaneous fission or in the r-process neutron emitters are produced naturally in natural reactors also by induced fission. The issue here is usually from an excited state of the nucleus of which was populated by a previous beta decay.

The half-life of the neutron emitters is generally very short and often is more than a few seconds. For the controllability of nuclear reactors, however, these nuclei play a central role with its delayed- neutrons.

Double neutron emission

Even rarer is the occurrence of a two - neutron decay. Here, not only one but two neutrons ejected simultaneously. Was observed such a decomposition for the first time in 2012 at the National Superconducting Cyclotron Laboratory ( NSCL ) at an artificial isotope of beryllium:

16BE → 14Be 2n