Types of radiation
The different types of radiation are often compared in terms of their The power of the radiation that demonstrates how far into a material the radiation will go., their To ionise is to convert an uncharged atom or molecule into a charged particle by adding or removing electrons. and how far they can travel in the air.
| Symbol | Penetrating power | Ionising power | Range in air | |
| Alpha | α | Skin/paper | High | < 5 centimetre (cm) |
| Beta | β | 3 mm aluminium foil | Low | ≈ 1 metre (m) |
| Gamma | γ | At least 40 mm lead or 2 m concrete | Very low | > 1 kilometre (km) |
| Alpha | |
|---|---|
| Symbol | α |
| Penetrating power | Skin/paper |
| Ionising power | High |
| Range in air | < 5 centimetre (cm) |
| Beta | |
|---|---|
| Symbol | β |
| Penetrating power | 3 mm aluminium foil |
| Ionising power | Low |
| Range in air | ≈ 1 metre (m) |
| Gamma | |
|---|---|
| Symbol | γ |
| Penetrating power | At least 40 mm lead or 2 m concrete |
| Ionising power | Very low |
| Range in air | > 1 kilometre (km) |
One example of a use of alpha radiation is in smoke detectors. A source of alpha radiation is used because the range is very low and alpha radiation has a very high ionising power.