Background Radiation and Contamination

What is background radiation?

Low-level radiation that’s around us all the time.

Where does backgroung radiation come from?

• Space (sun) - Earth’s atmosphere protects us from these.

• Air

• Food

• Building materials

• Human activity (e.g. nuclear explosions)

What is radiation dose?

Tells you the risk of harm to body tissues due to expore to radiation. It’s measured in sieverts (Sv) and millisieverts (1 Sv = 1000 mSv)

What’s the name for exposure to radiation?

Irradiation - means you are exposed to radiation. DOES NOT mean something is radioactive.

What are ways of reducing the effects of irradiation?

• Keeping sources in lead-lined boxes

• Standing behind barriers

• Using remote-controlled arms

What is contamination?

Unwanted radioactive particles getting into objects. Objects that are contaminated might decay and can you harm. This is dangerous because radioactive particles could get inside you body.

How can you prevent contamination?

Wearing gloves and tongs to avoid particles getting stuck to your skin or under you nails. some companies wear proctive suits to prevent them from breathing radioactive particles.

Danger of irradiation and contamination

They can cause different amounts of harm depending on the radiation type.
Outside the body, Beta and Gamma are the most dangerous because they can penetrate into the skin and affect delicate organs. Alpha isn’t as dangerous since it can’t penetrate into the skin and its easily blocked by a small air gap. However, high levels of irradiation are dangerous either way.

Inside the body, Alpha particles are most dangerous because they can do all their damage in a localised area. Beta sources are less damaging as radiation is absorbed over a wider area, and some passes out of the body. Gamma sources are the least dangerous because they pass straight out - they have the lowest ionising power.