Background radiation - is ionising radiation . Radioactivity that is naturally around us.
It comes from...
- space (cosmic rays)
- devices such as x-ray tubes.
- radioactive isotopes in the environment - Radon gas, gamma rays from rocks.
It can cause cancer, may also cause things like mutation.
Paper blocks ALPHA PARTICLES (or 5cm of air).
3mm of aluminium stops BETA PARTICLES.
Lead or thick concrete blocks GAMMA RAYS.
Isotopes - atoms with same number of protons, different numbers of neutrons.