An industrial thickness monitoring system is used in a factory to control the thickness of thin sheets of aluminium (about 1 mm thick) as they are rolled.
The table below shows information about three different radioactive isotopes.
| Isotope | Type of radiation emitted | Half-life |
|---|---|---|
| Polonium-210 | Alpha (α\alphaα) | 138 days |
| Strontium-90 | Beta (β\betaβ) | 28.8 years |
| Cobalt-60 | Gamma (γ\gammaγ) | 5.27 years |
Explain why Strontium-90 is the most suitable of these three isotopes to use in this industrial thickness monitoring system.
Use information from the table and your own scientific knowledge.
Your answer should refer to:
- The properties of alpha, beta, and gamma radiation (including penetration power and absorption).
- The significance of the half-lives of the isotopes in an industrial automation context.