Those Bolsheviks really loved their cobalt-60! The application of cobalt-60 to monitor erosion of refractory brick in the hearth block of a blast furnace at 4:50 in Part 2 of this film is not only clever but likely to induce cardiac arrest among denizens of Safetyland.
FDA loves Cobalt-60 too:
Cobalt-60 is an attractive gamma ray source for a number of reasons.
- It is easily made in nuclear reactors by irradiating natural cobalt-59, which is the only natural isotope of cobalt and an inexpensive, readily-available industrial metal.
- Cobalt is chemically inactive and not prone to corrosion.
- With a half life of 5.27 years, it is an intense radiation source (44 trillion decays per second per gram).
- It decays to nickel-60, which is non-radioactive and non-corrosive.
- Radiation consists of low energy beta and high energy gamma emission. The beta emission is easily shielded, resulting in a pure gamma source.
The only inconvenience is that the relatively short half-life means that the source decays quickly enough that dose must be calculated and adjusted based upon the age of the source since its production.