Radiation emitted by certain radioactive nuclei that decay during weak interactions. There are two types of beta decay: beta plus or beta minus. β+ decay occurs when a proton is converted into a neutron, while β- occurs when a neutron is converted into a proton. An electron antineutrino is also emitted. It is not a very penetrating type of radiation as a single sheet of aluminium or several metres of air will stop it.
