Irradiation and contamination
Irradiation
A torch beam lights up a person's hand because the hand is exposed to light, which is visible electromagnetic radiationEnergy travelling as waves in the form of changing electrical and magnetic fields.. Exposing objects to beams of radiationEnergy carried by particles from a radioactive substance, or spreading out from a source. is called irradiationProcess of exposing an object to a source of radiation. Eg fruit exposed to gamma rays in order to destroy bacteria is said to have been irradiated.. This term applies to all types of radiation, including radiation from the nucleiNuclei is the plural of nucleus. The nucleus is the central part of an atom. It contains protons and neutrons, and has most of the mass of the atom. of atomThe smallest part of an element that can exist..
Irradiation from radioactive decayThe process in which unstable atomic nuclei break apart or change, releasing radiation as they do so. can damage living cells. However, it can be put to good use as well as being a hazard.
Contamination
Contamination occurs if an object has a radioactiveWhen unstable atoms give off particles that can be harmful to humans. material introduced into it.
Irradiation versus contamination
The two processes of irradiation and contamination are often confused. However they are very different and useful in their own right.
| Irradiation | Contamination |
| Occurs when an object is exposed to a source of radiation outside the object | Occurs if the radioactive source is on or in the object |
| Does not cause the object to become radioactive | A contaminated object will be radioactive for as long as the source is on or in it |
| Can be blocked with suitable shielding | Once an object is contaminated, the radiation cannot be blocked |
| Stops as soon as the source is removed | It can be very difficult to remove all of the contamination |
| Irradiation | Occurs when an object is exposed to a source of radiation outside the object |
|---|---|
| Contamination | Occurs if the radioactive source is on or in the object |
| Irradiation | Does not cause the object to become radioactive |
|---|---|
| Contamination | A contaminated object will be radioactive for as long as the source is on or in it |
| Irradiation | Can be blocked with suitable shielding |
|---|---|
| Contamination | Once an object is contaminated, the radiation cannot be blocked |
| Irradiation | Stops as soon as the source is removed |
|---|---|
| Contamination | It can be very difficult to remove all of the contamination |