Gamma ray
After emitting an alpha or beta particle, the nucleus will often still be ‘excited’ and will need to lose energy.
It does this by emitting a high energy electromagnetic wave called a gamma ray.
Gamma radiation does not consist of particles but as short wavelength, high energy electromagnetic radiation emitted from unstable nuclei.
It is normally emitted alongside alpha or beta radiation.
Gamma radiation has no mass and no charge.
It can be written as γ or \(_{0}^{0}\textrm{γ}\)
An example of beta and gamma decay of cobalt-60
Beta and gamma decay of cobalt-60:
(2760ٱٰǰٲǷɳ2860ٱٰ+-10ٱٰ+00ٱٰγ)
Properties of nuclear radiations
The different types of radiation are often compared in terms of what stops them, 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 or a thin sheet of paper | High | less than 5 cm |
| Beta | β | 3 mm aluminium foil | Low | approximately 2 m |
| Gamma | γ | Lead/concrete | Very low | more than 1 kilometre (km) |
| Alpha | |
|---|---|
| Symbol | α |
| Penetrating power | Skin or a thin sheet of paper |
| Ionising power | High |
| Range in air | less than 5 cm |
| Beta | |
|---|---|
| Symbol | β |
| Penetrating power | 3 mm aluminium foil |
| Ionising power | Low |
| Range in air | approximately 2 m |
| Gamma | |
|---|---|
| Symbol | γ |
| Penetrating power | Lead/concrete |
| Ionising power | Very low |
| Range in air | more than 1 kilometre (km) |