- Homework Statement:
Hello, I have been revising and found a question concerning background radiation. I am not struggling too greatly to name the sources of background radiation but rather in understanding what the question is asking;
"Name the main sources of background radiation and state their relative importance"
By stating their relative importance does this mean state how greatly they contribute to the total background radiation? And perhaps considering how afflicting these sources are in relation to their dose? i.e. although radon gas is arguably the largest contributor less people are afflicted by this natural source than say the victims of the bombings of Hiroshima, even thought the total contribution of nuclear weapons is substantially less at ~0.3%.
Thank you to anyone who replies
- Relevant Equations:
- Background radiation
Several sources of background radiation include;
- Radon gas from soil, rocks and building minerals; since radon is produced by the decay of uranium ore present in certain rocks e.g. granite. On Earth, approximately 42-51% of background radiation is the result of naturally radioactive gases like radon.
- Cosmic rays; being charged particles from the the Sun and stars that collide with atoms in Earth’s upper atmosphere and magnetic field to produce an air shower of radiation, typically beta and gamma radiation, although most do not reach the surface of the Earth, contributing ~10-14% of the overall background radiation. The dose from cosmic radiation varies in due to differences in elevation and to the effects of the earth’s magnetic field at different locations on Earth.
- Another source of radiation is ingested internally from food and drink; as two of the essential elements of the human body, being potassium and carbon, have radioactive isotopes that significantly contribute to the background radiation dose on Earth at 9-12%.
- There are abundant artificial sources also, since human activity has contributed to the overall background radiation through the use of medical X-rays, implementing nuclear weapons testing and producing radioactive waste from nuclear power stations.
- In particular, medical imaging, e.g. using X-rays, and employing radioisotopes for diagnostics and radiation treatment contribute 12-15% of the overall background radiation.
- Nuclear testing in the between the 1940s-1960s resulted in a substantial increase in radioactive contamination which affected not just the immediate surrounding area but additionally dispersed globally, i.e as a result of nuclear fallout, contributing ~ 0.3%