cobalto60

Cobalt-60 is a radioactive isotope of cobalt (Co) with 27 protons and a mass number of 60. It is not found in significant quantities in nature and is produced artificially by irradiating cobalt-59 in a nuclear reactor through neutron capture. The resulting cobalt-60 is used in various sealed-source applications after encapsulation to contain its radioactivity.

Cobalt-60 decays by beta minus emission to nickel-60 and emits high-energy gamma rays, with principal emissions at approximately 1.17 MeV and 1.33 MeV. Its half-life is about 5.27 years, meaning the activity of a cobalt-60 source decreases by roughly half every five years. Because of the gamma radiation, proper shielding—commonly lead or concrete—is required for safety, and sources must be handled with licensed procedures and equipment.

The most well-known use of cobalt-60 is in external beam radiotherapy, where its gamma rays target cancerous tissue. Historically it powered teletherapy units and, in specialized devices such as the Gamma Knife, cobalt-60 sources are arranged to deliver precise doses to the brain. Other major applications include industrial radiography for nondestructive testing, sterilization of medical devices and some foods, and the irradiation-assisted modification of polymers.

Safety and regulation are central to cobalt-60 handling. Sealed sources are designed to prevent leakage, but damaged or spent sources require secure containment, transport, storage, and eventual disposal according to national and international guidelines.