Nuclear or ionising radiation can be emitted by the nuclei of atoms undergoing radioactive decay, produced by machines by the acceleration of charged particles or by the fusion or fission of atoms1.
Ionising radiation forms a portion of the energy released by unstable nuclei (called radionuclides) undergoing radioactive decay. It includes sub-atomic alpha particles, beta particles and neutrons, in addition to electromagnetic waves such as x-rays and gamma rays1. The ‘ionising’ portion of ionising radiation originates from its ability to detach electrons from atoms due to the significant amount of energy they inherit from the radioactive decay process1. This is detrimental as ionisation can lead to damage to biological tissue, malfunctioning cells and DNA mutation1. The extent of damage done is relative to the type of ionising radiation, the effected tissue (such as reproductive organs, which suffer from much more damage), the amount of exposure in a certain time frame and the type of exposure (internal or external). The culmination of all of these variables is measured as a ‘dose’ and the amount of dose is key to the symptoms of radiation exposure.
Naturally-occurring vs human-made radiation
All living things are exposed to natural background radiation, which comes from three main sources2:
- Cosmic radiation directly from space, such as the energy released from the fusion of hydrogen and helium in our own Sun.
- Ionisation of the Earth’s atmosphere by cosmic rays, creating sub-atomic particles like muons, mesons and positrons
- Terrestrial radiation from soil, water, vegetation and the Earth’s crust.
These forms of background radiation are all naturally occurring. However, many human-made process result in the production of radioactive materials as well2. The most significant source of human-made radiation exposure to the public is from medical procedures, which includes x-rays, nuclear medicine and radiation therapy2. Some consumer products, such as building material, smoke alarms, combustible fuels, can also release varying levels of radiation2. Fallout from nuclear testing and small quantities of radioactive materials released to the environment from coal and waste from nuclear power plants are also sources of radiation exposure3.
The risk of significant exposure arises when human-made radioactive sources are stolen or go missing, or when high concentrations of radioisotopes are released into the environment following nuclear accidents or attacks. Both can potentially lead to widespread contamination and uncontrolled radiation exposure to the public.
If we’re always exposed to radiation, how do we know what’s considered safe and what isn’t?
How do you tell the difference?
That’s where reliable, radiation detection comes in. The ability to rapidly distinguish dangerous sources from less harmful natural or medical sources is crucial for informing next steps in decontamination and ensuring the safety of people and the environment. Take Southern Oregon Sanitation for example! They avoided an expensive 200-day shutdown by using the D3M and D5 RIID to correctly identify a misidentified radionuclide, therefore effectively mitigating the incident without wasting time and money.
Scaling up to regional, national and international detection networks also ensures that widespread contamination caused by nuclear or radiological (R&N) incidents or unregulated radioactive sources can be effectively monitored and minimised. The relevant authorities can be alerted to the incident in its early stages, facilitating rapid, coordinated responses. Accurate data from networked detectors ensures the appropriate actions are carried out.
Stay tuned as we dive deeper into all the different places and forms radiation can show up in this five-part blog series.
Sources:
2 – USNRC Technical Training Centre | Natural and Man-Made Radiation Sources
3 – Radiation in Everyday Life | IAEA
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