Ionizing radiation is a type of energy released by atoms in the form of electromagnetic waves or particles. The energy of such a physical reaction is so great that it is able to enter into relationships with other substances, modifying and creating ions of different signs.
There are several types of radiation: alpha, beta and gamma particles, neutrons and X-rays.
are rather heavy particles, positively charged, they represent helium nuclei. To protect against alpha particles you only need a dense sheet of paper, thus, external alpha radiation is absolutely not dangerous to humans.
are ordinary electrons. The size of beta particles is much smaller than alpha ones, so that they can penetrate into the human body. Beta particles can be stopped by an aluminum plate with 1/12 inches thickness.
have the same nature as visible light, but much greater penetrating power.
are electrically neutral particles, arising mainly near nuclear reactors. Access to it should be limited.
are similar to gamma-radiation, but have less energy. The sun is one of the natural sources of these rays, but the Earth's atmosphere protects us from solar radiation.
The most dangerous radiation for human is alpha, beta and gamma radiation, which can lead to serious diseases, genetic disorders and even death. The degree radiation’s influence on human health depends on the type of radiation, time and frequency. One-time exposure to a strong source of radiation (natural or artificial) and prolonged storage of low-level radioactive items can have the same harmful effect to human.
During the radioactive decay the human body receives a dose of energy (which is referred as to irradiation), which affects the living cells, thereby destroying them. Radiation affects dividing cells in particular, so it is especially dangerous for children.
Radiation is also dangerous when it comes 'from the inside.' Radioactive particles enter the body with inhaled air, food or water.
The radiation level of beta and gamma particles is measured by a dosimeter using a Geiger-Muller tube.
The level of radiation is expressed as an amount of radiation in micro Sievert (µSv) per hour of exposure.