Cobalt 60 is a radioactive isotope capable of breaking down to produce gamma
rays. Gamma rays are electromagnetic waves that have the ability to penetrate
a much greater distance than beta rays before losing their energy from
collision. Because they travel with the speed of light, they must pass through a
thickness measuring several feet before making sufficient collisions to lose all of their
energy. Cobalt 60 is the most commonly used source for irradiation sterilization.