Cobalt-60
| General | |
|---|---|
| Symbol | 60Co |
| Names | cobalt-60 |
| Protons (Z) | 27 |
| Neutrons (N) | 33 |
| Nuclide data | |
| Natural abundance | trace |
| Half-life (t1/2) | 5.27 years |
| Isotope mass | 59.9338222 Da |
| Spin | 5+ |
| Decay modes | |
| Decay mode | Decay energy (MeV) |
| β (beta decay) | 0.317 |
| γ (gamma-rays) | 1.1732,1.3325 |
| Isotopes of cobalt Complete table of nuclides | |
Cobalt-60 (60Co) is a synthetic radioactive isotope of cobalt with a half-life of 5.2714 years.: 39 It is produced artificially in nuclear reactors. Deliberate industrial production depends on neutron activation of bulk samples of the monoisotopic and mononuclidic cobalt isotope 59
Co. Measurable quantities are also produced as a by-product of typical nuclear power plant operation and may be detected externally when leaks occur. In the latter case (in the absence of added cobalt) the incidentally produced 60
Co is largely the result of multiple stages of neutron activation of iron isotopes in the reactor's steel structures via the creation of its 59
Co precursor. The simplest case of the latter would result from the activation of 58
Fe. 60
Co undergoes beta decay to an excited state of the stable isotope nickel-60 (60
Ni), which then emits two gamma rays with energies of 1.17 MeV and 1.33 MeV. The overall equation of the nuclear reaction (activation and decay) is: 59
27Co + n → 60
27Co → 60
28Ni + e− + ν
e + 2γ