Properties of radiation and ionisation

Certain nuclei are unstable, meaning they will undergo radioactive decay and emit radiation to become more stable.
This radiation can ionise atoms, causing them to become ions.
Activity is the rate of radioactive decay, measured in Becquerels (emissions per second).
Detectors, such as a Geiger-Muller tube, can measure radioactivity by counting the number of particles entering it. This will give a count rate as the number of decays recorded per second.
Nuclear radiation comes in multiple forms:
- Alpha particles \((\alpha)\) consisting of two protons and two neutrons released from the nucleus (the same as a helium nucleus).
- Beta particles \((\beta)\) consisting of a high-speed electron. A neutron will turn into a proton to release this.
- Gamma rays \((\gamma)\) consisting of electromagnetic radiation from the nucleus.
- A neutron \((\text{n})\) released from the nucleus.

Radiation is harmful to the body as it can damage cells and tissues.
- Alpha radiation is the most damaging inside the body as it is the most ionising.
- Gamma radiation is the most damaging outside the body as it can penetrate the body from far away.

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