Neutron radiation

Neutron radiation consists of energetic neutrons emitted most often from radioactive decay of atomic nucleii. The neutrons are generally catagorized as slow (thermal) neutrons or fast neutrons. Thermal neutrons are easily captured by atomic neucleii and are the primary means by which elements undergo atomic transmutation. Fast neutrons on the other hand more often cause fission and so are useful in nuclear reactors and bombs. The element beryllium is particularly useful due to its ability to act as a neutron reflector or lens. This allows smaller quantities of fissile material to be used and is a primary technical development that led to the creation of neutron bombs.