Background Radiation, Hazards & Uses [Physics only]

Background radiation

• Background radiation is around us all the time. It comes from:
  • Natural sources: rocks (radon gas from granite), cosmic rays from space, food and drink, the air
  • Man-made sources: fallout from nuclear weapons testing and nuclear accidents, medical procedures
• The level of background radiation and a person's radiation dose depend on occupation (radiographers, pilots, nuclear workers) and location (granite areas such as Cornwall have more radon)
• Radiation dose is measured in sieverts, Sv; 1000 millisieverts (mSv) $=$ 1 Sv. You do not need to recall the unit
• Background must be measured and subtracted from readings when a source is investigated