LOJ Feb 2004

Radioactivity 3

Background radiation

LOJ Feb 2004

'Mr. Average UK‘ – Background dose

LOJ Feb 2004

Background radiation

• There are radioactive substances all around us, including in the ground, in the air, in building materials and in food.

• Radiation also reaches us from space. • The radiation from all these sources

is called background radiation.

LOJ Feb 2004

Background Radiation

• Most of the background radiation dose we receive in the UK is from natural sources (about half is inhaled as radon gas).

• About 15% of our annual dose comes from human activities such as X-rays in hospital or at the dentist or emissions from nuclear establishments.

LOJ Feb 2004

Your Background Radiation DoseThe radiation dose you get in a year depends on:

– where you live (the rock type in your locality), – your state of health (whether you require

treatment or investigation in hospital that involves ionizing radiation ),

– your diet (salt substitutes contain potassium rather than sodium and the percentage of potassium that naturally occurs in the radioactive form is higher than that of sodium),

– your occupation (do you work in an environment that exposes you to nuclear radiation?)

LOJ Feb 2004

Experiments

• You need to count the background radiation before you perform an experiment.

• The background count can then be deducted from the count in your experiment.