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Cobalt-60 (60 Co) is a synthetic radioactive isotope of cobalt with a half-life of 5.2714 years. [ 3 ] [ 4 ] : 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
Cobalt therapy is the medical use of gamma rays from the radioisotope cobalt-60 to treat conditions such as cancer. Beginning in the 1950s, cobalt-60 was widely used in external beam radiotherapy (teletherapy) machines, which produced a beam of gamma rays which was directed into the patient's body to kill tumor tissue.
The deposited cobalt-60 would have a half-life of 5.27 years, decaying into 60 Ni and emitting two gamma rays with energies of 1.17 and 1.33 MeV, hence the overall nuclear equation of the reaction is: 59 27 Co + n → 60 27 Co → 60 28 Ni + e − + gamma rays. Nickel-60 is a stable isotope and undergoes no further decays after the ...
This reaction has a half-life of about 5.27 years, and due to the availability of cobalt-59 (100% of its natural abundance), this neutron bombarded isotope of cobalt is a valuable source of nuclear radiation (namely gamma radiation) for radiotherapy. [1] 59 27 Co + 1 0 n → 60 27 Co
Cobalt-60 Production: The least complex of current uses of the Advanced Test Reactor is the production of the 60 Co radioisotope for medical uses. Disks of cobalt-59 1 mm -diameter by 1 mm thick are inserted into the reactor (Static Capsule Experiment), which bombards the sample with neutrons, producing cobalt-60.
Cobalt-60 beam machine from 1951 Cobalt units use radiation from cobalt-60, which emits two gamma rays at energies of 1.17 and 1.33 MeV, a dichromatic beam with an average energy of 1.25 MeV. The role of the cobalt unit has largely been replaced by the linear accelerator, which can generate higher energy radiation.
A typical cobalt-60 capsule, comprising: (A) An international standard source holder (usually lead), (B) a retaining ring, and (C) a teletherapy "source" composed of (D) two nested stainless steel canisters welded to two (E) stainless steel lids surrounding an (F) internal shield (usually uranium metal or a tungsten alloy) that protects a (G) cylinder of radioactive source material.
After retrieval from the core, processing can extract the cobalt-60 for manufacture into a useful radiation source. The vast majority of the world's cobalt-60 supply - over 80% - has traditionally come from Canada's National Research Universal (NRU) reactor at Chalk River. In general, the supply situation for medical and industrial isotopes is ...