Production of Cobalt-60
Radioactive cobalt-60 was discovered by Glenn T. Seaborg and John Livingood at the University of California - Berkeley in the late 1930's. By bombarding cobalt 59 with neutrons, in a nuclear reactor, an additional neutron can be captured by the nucleus converting it into cobalt 60. Placing this non-radioactive, Cobalt-59 pellets into a nuclear reactor creates deliberately produced cobalt-60. Over time cobalt-59 absorbs a neutron to become cobalt-60. After removal from the
reactor the cobalt-60 is double enclosed in stainless steel sealed sources.
Cobalt-60 emits Beta and Gamma Rays. Where Beta radiation is present, shielding may be required. Cobalt-60 is unstable and in trying to become stable it emits a beta-particle and two photons of gamma radiation. An isotope of nickel will remain.
Methods of Detection:
Methods of Detection:
- A radiation survey meter equipped with an energy-compensated Geiger Mueller detector.
- Ion chamber survey meter – tends to be less sensitive than a Geiger Mueller survey meter but is able to respond more precisely in higher radiation fields.
- Gamma scintillation detector – very sensitive but is also energy dependent. Must be calibrated for Co-60 before it can be used for dose assessment surveys.