background radiation and contamination

• what is background radiation?

  The low-level radiation that's around us all the time
• Examples of background radiation

  air, food, rocks underneath our feet, cosmic rays from the sun, human activity - nuclear waste
• what does radiation dose tell us?

  tells us the risk of harm to body tissues due to the exposure of radiation
• what is radiation does measured in?

  Sieverts (Sv)
• what is background radiation measured in?

  millisieverts (mSv) because background radiation is very small

  1 Sv = 1000 mSv
• what does the amount of background radiation depend on?

  where you live and what job you have
• What is irradiation?

  exposure to radiation

  objects near a radioactive source irradiated by it
• does being irradiated by something make it radioactive?

  no
• how can you reduce irradiation?

  keeping sources in lead-lined boxes, standing behind barriers, being in a different room and using remote controlled hands
• What is contamination?

  when unwanted radioactive atoms get onto or into an object
• what might happen to the contaminating atoms?

  they might decay releasing radiation which could cause you harm
• how to reduce contamination?

  gloves and tongs to avoid particles getting onto skin or under nails

  some workers wear protective suits to stop them breathing in particles
• what are the most dangerous sources outside the body and why?

  beta and gamma - they can penetrate the body and get in delicate organs
• what are the least dangerous sources outside the body and why?

  alpha - cant penetrate the skin and easily get blocked by a small air gap
• what is the most dangerous inside the body and why?

  alpha - they do all their damage in a very localised area
• what is the least dangerous inside the body and why?

  beta - radiation is absorbed over a larger area

  gamma - they mostly pass straight out - lowest ionising power