Gamma radiation is the product of radioactive atoms. Depending upon the ratio of
neutrons to protons within its nucleus, an isotope of a particular element may be
stable or unstable. When the binding energy is not strong enough to hold the nucleus
of an atom together, the atom is said to be unstable. Atoms with unstable nuclei are
constantly changing as a result of the imbalance of energy within the nucleus. Over
time, the nuclei of unstable isotopes spontaneously disintegrate, or transform, in a
process known as “radioactive decay” and such material is called “radioactive
material”.