Neutron radiation is a form of ionising radiation consisting of free neutrons.
Neutron radiation is rarely produced by the natural decay of atomic nuclei. It is usually produced artificially with the help of neutron sources; neutron radiation is also released during nuclear fission.
Since neutrons are electrically neutral and their motion is therefore not influenced by atomic nuclei and electrons, they penetrate matter relatively easily. The free state of a neutron is always terminated very quickly by neutron capture or another nuclear reaction.