Ionizing radiation is a natural part of our surroundings and environment. We are literally surrounded by it. It comes to us from outer space, is emitted by the Earth's crust and building materials, we breathe air containing radon, we eat bananas containing radioactive potassium, our bodies contain radioactive carbon and tritium, and from time to time we undergo a chest X-ray. When all these contributions are added together, the average annual dose received by a Czech citizen is about 3 mSv. Almost half of this dose comes from radon, which is the most significant source of radiation exposure in the Czech Republic. For comparison, the annual dose limit for radiation workers defined by atomic legislation is 20 mSv.
Ionizing radiation is a good servant. In nuclear power plants it produces heat, in medicine it saves lives, and in the food industry it kills bacteria and viruses. Technologies based on ionizing radiation help to build a modern society. To ensure that this good servant does not become a bad master, we must approach these technologies with respect and follow the principles of nuclear safety and radiation protection.
The remote experiments provide an opportunity to familiarise yourself with the fundamental principles of radiation protection, particularly the time – distance – shielding rule.
- The shorter the time we spend in contact with a radiation source, the smaller the dose we receive. The rule therefore states: “Handle the radiation source for the shortest possible time”. This may sound trivial, but this principle is very easily violated in practice.
- The intensity of radiation decreases with the square of the distance from the source. If we move twice as far away, the received dose is four times lower. The rule therefore states: “Stay as far from the radiation source as possible”. In real facilities, ionizing radiation sources are handled from a safe distance using appropriate manipulators or robotic arms. Explore this principle in the experiment Radiation Intensity as a Function of Distance.
- Radiation is attenuated in matter. Its intensity decreases when a suitable shielding material is placed between the radiation source and a person. The design of shielding is an essential part of all projects that use radiation – from nuclear power plants to medical accelerators. Explore this principle in the experiment Shielding Properties of Materials.
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