Which isotope is commonly used as a gamma radiation source?

Cobalt-60 is commonly used as a gamma radiation source due to its properties and applications in various fields, especially in medical treatment and industrial radiography. This isotope undergoes beta decay to produce an excited state of nickel-60, which subsequently emits high-energy gamma rays as it transitions to its stable ground state. These gamma rays have significant penetrating power, making cobalt-60 effective for treating certain cancers, sterilizing medical equipment, and conducting non-destructive testing of materials.

In comparison, while Iodine-131 is used in medical applications, particularly for thyroid treatment, it emits beta particles along with gamma photons. Cesium-137 also emits gamma radiation and is used similarly to cobalt-60 but is less prominent in practical applications. Tritium-3, on the other hand, is primarily a beta-emitting isotope and is not typically used as a source of gamma radiation.