Radiation is everywhere in our environment. It comes from space, from the microwave, from the transmission mast or from radioactive traces in the rock. Many forms of radiation penetrate the body every day without endangering health. But some can harm cells from a certain dose. In these cases, protective measures are necessary.
The term radiation describes the propagation of waves and particles in space. It thus covers the entire spectrum of electromagnetic waves, starting with low-energy, low-frequency infrared heat radiation in the kilohertz range. These include, for example, the heat radiation of the sun or the microwave radiation. The visible light that our eye can perceive has a higher frequency with wavelengths of 400 to 700 nanometers. It can be dangerous in short-wave UV light, which sends the sun to Earth and can cause sunburn and, in the worst case, even skin cancer.
Ionizing and non-ionizing radiation
Radiation can interact with matter, depending on the type and energy content of a single “radiation particle”. Electromagnetic radiation up to UV radiation is part of the non-ionizing radiation, although it can stimulate particles to vibrations and thus heat substances, but do not release the bonds within an atom or molecule. It is different with ionizing radiation, it can knock electrons out of atomic shells. What remains are ionized like charged, atoms and molecules. These can trigger further reactions and thereby damage cells or cell components in the body.
Gamma radiation occurs when many radioactive elements decay when some of the energy is emitted in the form of radiation. It has a long range and can easily penetrate matter, so thick layers of lead or concrete are required to shield it. If it passes through human tissue, part of it is absorbed. Electrons can be released from the atomic shells and the genetic material of the cells can be damaged, so that they no longer divide properly. Therefore, the so-called radiation disease, which is triggered by a short-term very high radiation sedation, often leads to death only after some time.
Alpha radiation consists of double positively charged helium nuclei, each composed of two protons and two neutrons. It arises from the alpha decay of radioactive nuclei. When slow alpha particles interact with atoms, they can capture electrons from the atomic shells, making the helium nuclei a noble gas helium.
The helium nuclei have a strong ionizing effect on matter. However, the distance of alpha radiation in air is short, depending on the energy of the particle and the prevailing air pressure, it is usually only a few centimeters. That’s why a piece of paper is enough to shield it. In order to protect yourself from alpha radiation, one should therefore keep distance from the radiation source.
Beta radiation consists of either electrons or their positive siblings, the positrons. It arises from the beta decay of radioactive isotopes. A distinction is made between beta positive and beta negative decay. Beta(-)- decay occurs in atomic nuclei with neutron surplus. One of the neutrons of the nucleus transforms into a proton by sending an electron and an antineutrino. Beta(+) decay occurs at high protons. A proton transforms into a neutron by sending a positron and a neutrino.
The energy distribution of beta radiation from radioactive nuclei is very different and reaches up to two MeV. In air, the range of beta radiation of phosphorus isotope 32 (1.7 MeV) can be up to seven meters; the range of the beta radiation of tritium (19 keV) on the other hand, only eight centimeters. Layers of denser materials such as aluminum, glass or plexiglass shield off beta radiation at a thickness of just a few millimeters.