Contamination and irradiation
Contamination and irradiation
is when unwanted radioactive atoms get onto or into an object or person. The atoms keep decaying, so the danger lasts until they are removed or have decayed. Inside the body, is the most dangerous, because it is strongly ionising and all its energy is absorbed by nearby cells.
is when an object is exposed to radiation from a source outside it. The object does not become radioactive, and the exposure stops when the source is removed or shielded. Outside the body, and are the most dangerous, because they can pass through skin.
Common mistake
An irradiated object is not radioactive. Food irradiated to kill bacteria is safe to eat.
Key terms
Staying safe
People who work with radioactive sources protect themselves by:
- handling sources with tongs and wearing gloves, to avoid contamination
- keeping as far away as possible and spending as little time near the source as they can
- using shielding, such as lead screens, and storing sources in lead-lined boxes
- wearing a badge that records how much radiation they have received
It's important that scientists publish their findings about the effects of radiation, so other scientists can check them by .