particles or penetrating rays emitted by a radioactive source. (see alpha radation, beta radiation, gamma radiation, radiation)
Ionizing radiation (alpha, beta, and gamma) originating in the nuclei of radioactive atoms.
Nuclear radiation emanates from the nucleus of an atom. It is ionising radiation. There are four types of nuclear radiation, three are made of matter: alpha, beta and gamma and the fourth is an antimatter particle: the positron.