Gamma Ray 02 : Electromagnetic radiation capable of great penetration; it is emit-ted by the nucleus of a radioactive substance and is shorter in length than an x-ray
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}