Background Radiation

• Background Radiation


  Low-level radiation that's around us all the time
• Forget love-radiation is all around. Don't panic too much though, it's usually a pretty small amount.
• Sources of background radiation

  • Radioactivity of naturally occurring, unstable isotopes
  • Radiation from space, which is known as cosmic rays
  • Radiation due to human activity, eg fallout from nuclear explosions or nuclear waste
• The Earth's atmosphere protects us from much of the cosmic radiation
• Radiation dose


  Measure of the risk of harm to body tissues due to exposure to radiation
• Sieverts (Sv)


  Unit used to measure radiation dose
• Millisieverts (mSv) are often used to measure background radiation (1Sv = 1000 mSv)
• Your radiation dose is affected by where you live and whether you have a job that involves radiation
• Other factors, such as having x-rays taken, also affect your radiation dose
• Irradiation


  Objects near a radioactive source are exposed to it
• Irradiating something does not make it radioactive
• Reducing irradiation


  1. Keeping sources in lead-lined boxes

  2. Standing behind barriers

  3. Being in a different room

  4. Using remote controlled arms when working with radioactive sources
• Background radiation comes from many sources, from food and drink to cosmic rays, but mostly it comes from the ground and is given out by certain rocks, like granite
• Areas like Cornwall and Devon, where there's lots of granite, have higher background radiation levels than is average for the UK