 These isotopes emit radiation in a discrete set of energies, depending on the decay mechanism happening in the atomic nucleus.Each energies will have different intensities depending on the probability of a particular decay interaction.The most prominent energies in Cobalt-60 are 1.33 and 1.17 MeV, and 0.31, 0.47 and 0.60 MeV for Iridium-192.