ABSTRACT
Radiation is the emission or propagation of energy through space. As such, it includes not only alpha and beta particles, gamma and X-rays, and neutrons but also visible light, radio waves, microwaves, infrared, and ultraviolet light. The first five types of radiation are generally emitted during the process of nuclear decay or fission, events involving the nucleus of atoms with the exception of X-rays, and are what we usually mean when we refer to radiation. The last five are different in that they do not typically originate with nuclear events and they are considered non-ionizing radiations, that is, they do not possess sufficient energy to knock an electron out of its orbit in an atom, ionizing the atom.
