Radiation Protection


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Understanding Radiation

Understanding Radiation

Australians are exposed to radiation from a variety of natural and artificial sources. Radiation is energy travelling as waves or particles. Ionising radiation has enough energy to change the chemical composition of matter. Non-ionising radiation has less energy but can still excite molecules and atoms causing then to vibrate faster.

What are some natural sources of ionising radiation?

Ionising radiation is the energy produced from natural and artificial radioactive materials. It is present in the environment because of naturally occurring radioactive minerals remaining from the very early formation of the planet. This leads to exposure to gamma rays and radioactive radon gas from certain rocks and from radioactive material in our food and drink. We are also exposed to natural ionising radiation that comes from outer space and passes through the atmosphere of the planet – so-called cosmic radiation.

What are some artificial sources of ionising radiation?

There are three main sources of artificial ionising radiation. They are:

  • medical uses including diagnosis of many diseases and treatment of cancer;
  • industrial uses, mainly in measurement and scientific research; and
  • fallout from nuclear weapons testing and accidents around the world.

The figure below shows the relative annual per capita dose to the Australian population from the various radiation sources

Pie chart showing annual per capita radiation dose from natural and medical sources - cosmic (0.3 mSv); Terrestrial (0.6 mSv); Radon and progeny (0.2 mSv); Potassium-40 in the body (0.2 mSv); Uranium/Thorium in the body (0.2 mSv); Atmospheric weapons testing (<0.005 mSv); Medical (1.7 mSv)

Is artificial radiation more dangerous than natural radiation?

The damaging effects of ionising radiation come from the packages of high energy that are released from radioactive material. Although different types of ionising radiation have different patterns of energy release and penetrating power (see ionising radiation topics) there is no general property that makes artificial ionising radiation different and more damaging than the ionising radiation that comes from natural radioactive material. This means that we can make direct comparisons between doses from artificial sources of ionising radiation and those from natural sources.

What are some examples of non-ionising radiation?

Solar radiation consists of several different forms of non-ionising radiation and many modern technologies such as, power-lines, electrical equipment and mobile phone systems, also produce forms of non-ionising radiations.

We cannot eliminate radiation from our environment but by having a good understanding of radiation and controlling our exposure, we can reduce our risk.

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