Radioactive Emissions

• Radioactive Emissions can be divided into three main types: Alpha particles, Beta particles, and Gamma rays.

• Alpha particles (α) are the heaviest and largest of the radioactive emissions. They are composed of 2 protons and 2 neutrons. This makes them identical to Helium nuclei.

• These particles carry a +2 charge due to their 2 protons. This gives them a relatively high ionising power, making them potentially damaging, but also, due to their significant mass, they are not highly penetrative and can be stopped by a sheet of paper or human skin.

• Beta particles (β) are essentially high-speed electrons ejected from the nucleus of a radioactive atom. This emission is the result of a neutron in the nucleus splitting into a proton and an electron.

• Beta particles have a single negative charge. Their ionising power is lower than that of alpha particles, but they are more penetrative and can penetrate through a few millimetres of aluminium.

• Gamma rays (γ) are not particles like alpha and beta, but instead are a type of electromagnetic radiation, similar to X-rays or light, but of a much higher energy.

• Gamma rays have no charge and, as such, their ionising power is the lowest among the three types of emissions. However, their penetration power is the highest. They can pass through several centimetres of lead and are only stopped by several metres of concrete.

• Radioactive emissions can be detected with instruments such as Geiger-Muller counters or photographic film badges, which become darker when exposed to radiation.

• All three types of radiation can cause ionisation, in which atoms or molecules gain or lose electrons and thus become ions. This ionisation can cause harm to living cells, but can also be harnessed for use in radiotherapy and sterilisation.

• Radioactive decay, the process in which unstable atomic nuclei break down and emit radiation, is random and cannot be predicted for individual atoms. However, the average rate of decay for a large number of atoms, described by an isotope’s half-life, is predictable.

• Understanding the different properties of these types of radiation is useful when choosing suitable precautions and is crucial to the safe handling and usage of radioactive sources.