Background radiation is low-level radiation that is always around us
Definition
Background radiation
The low-level nuclear radiation that is present around us all the time, coming from natural and man-made sources.
- Background radiation is the small amount of radiation that is around us all of the time.
- Most of it comes from natural sources, with a smaller part from man-made sources.
Natural and man-made sources both add to the background
- Natural sources include rocks, which can release radon gas, and cosmic rays that reach us from space.
- Man-made sources include the fallout from nuclear weapons testing and from nuclear accidents.
- Your background level depends on your location and your occupation, so a pilot or a radiographer receives more than most people.
Radiation dose is measured in sieverts
Definition
Radiation dose
A measure of the possible harm done to the body by radiation, measured in sieverts (Sv).
- Radiation dose measures the risk of harm that radiation can do to the body, and is measured in sieverts (Sv).
- Doses are usually small, so they are often given in millisieverts, where 1000 mSv=1 Sv1000\ \text{mSv} = 1\ \text{Sv}1000 mSv=1 Sv.
- To change millisieverts into sieverts, divide by 100010001000.
Example
Convert a dose of 35 mSv35\ \text{mSv}35 mSv into sieverts.
35 mSv=351000 Sv=0.035 Sv 35\ \text{mSv} = \frac{35}{1000}\ \text{Sv} = 0.035\ \text{Sv} 35 mSv=100035 Sv=0.035 SvSelf review
- What is background radiation?
- Give one natural and one man-made source of background radiation.
- How can occupation or location change the radiation dose someone receives?
- What unit is radiation dose measured in?
- Convert 250 mSv250\ \text{mSv}250 mSv into sieverts.
