In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through some material medium. In short, radiation is movement of energy. This includes the movement of electro-magnetic radiation such as radio waves, microwaves, visible light, x-rays, and gamma radiation, particle radiation such as alpha (α) radiation, beta (β) radiation, acoustic radiation such as ultrasound, sound, and seismic waves.
Radiation is often separated into two categories, either ionising or non-ionising depending on the energy of the radiation. Ionising radiation carries more than 10 eV (electron Volts) of energy, which is enough to ionise atoms and molecules, and break chemical bonds. The distinction between ionising and non-ionising is important due to the large difference in harmfulness to living organisms, largely due to the interaction processes with matter.
All forms of radiation may have harmful effects if exposure to the radiation is at high enough levels. Conversely all forms of radiation have levels at which harm from exposure con no be measured. Therefore radiation requires risk mitigation considerations.
Common sources of ionising radiation that may require management include:
- Artificial radioactive materials that emit α, β, or γ radiation, used in:
- Industrial gauging
- Tracer studies
- Naturally Occurring Radioactive Materials (NORM) in mining, exploration, oil and gas production
- Medical X-rays from radiography examinations
- Industrial X-ray sources such as on-stream analysers and NDT.
Common sources of non-ionising radiation that may require management include:
- Microwave/mobile phone communications towers
- High intensity visible light (eg cosmetic IPL)
- Lasers – industrial and recreational
- Radio towers
- ‘Soft’ UV lighting