Gamma rays were discovered by Villard more than a hundred years ago. Rutherford gave the name -rays to the electrically neutral radiation emitted by the naturally occurring radioactive materials. Gamma rays are electromagnetic radiation, photons, which arises due to energy changes in the nucleus. It does not appear as an independent form of radiation, but it follows and β decay, in those cases when the newly created core of the offspring is found in the excited state. This state is very short, while the excited nucleus in its transition to a lower energy level or the primary energy state, mosty usually transmits - photons or transfers.
