Radioactive decay, activity and count-rate

你需要知道的

• Some isotopes have unstable nuclei, which give out radiation to become more stable; this is radioactive decay.
• Radioactive decay is random, so we cannot predict when a particular nucleus will decay.
• Activity is the rate at which a source decays, measured in becquerels (1 Bq is one decay per second).
• Count-rate is the number of decays a detector such as a Geiger-Muller tube records each second, which is not the same as activity.
• The four types of radiation are alpha particles, beta particles, gamma rays and neutrons.

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