BSL Physics Glossary - background radiation - definition
There is radiation in our environment all the time. This device can measure it. It's a radiation meter that tells us how much radiation there is. It could be radiation from the Earth or from the environment. Have a look.
The meter is showing 11 now. We can move the detector round. It's still going up. This background radiation is always there, but it doesn't affect us. It's a very small amount of radiation. Its origin is the Earth and the Sun.
It's got to 18 now. This background radiation is always around us, but it doesn't affect us.