The Earth’s natural background radiation is radiation that is created by radionuclides present in air, water, earth, living organisms, food, and cosmic radiation.
The planet's population receives most of the exposure from natural sources, while avoiding most of them is not possible. Throughout the history of the globe, various types of radiation from active substances from the soil and space have come to the surface. They act on the body as follows: the substances are outside and irradiate it from the outside, this is radiation of the external type, or they are present in water, products, in the inhaled air and enter the human body. This method is called internal.
Degree of exposure
The natural background radiation affects every inhabitant of the planet, but some have a greater impact than others. In particular, the region of residence influences this. In some places of the Earth, where there are more radioactive rocks, the level is above average, and in others it is lower. Depends on the degree of exposure and lifestyle. Traveling by plane, sealing the room, using open-type coal-fired fryers and gas for cooking, the use of certain building materials increases the amount of radiation.
Radiation from space
The influence of the rays makes up an equal share of the total radiation that falls on the population. Cosmic rays are formed from high-energy flows, electrons, photons and nuclei of simple particles. But the Earth has protective mechanisms that protect against the effects of radiation, without them life would have become impossible.
The magnetic background repels cosmic elements and creates strong protection, but not perfect. Some energy particles seep through the barrier and reach the atmospheric layers. Only a small part manages to pass all the obstacles and reach the surface layer. Basically, when they collide with atoms, they interact with the nuclei, they break up and new particles are created that form the natural radiation background.
How does cosmic radiation work?
It is impossible to protect yourself from invisible flows. But the Earth’s surface is exposed differently to them. The poles receive a greater amount of radiation compared to the equator region, since the magnetic field is weaker here. The degree of radiation increases markedly with increasing height, as the air gap becomes smaller. Passing through the atmosphere, the rays contribute to the emergence of cosmogenic radionuclides.
For cosmonauts, radiation earth belts pose a serious threat during prolonged flights near the planet, if their orbit intersects with the region of the belts. A prolonged stay in it leads to excessive irradiation of the crew, and damage to batteries located on board optical devices is also possible. In this regard, a lot of research is being carried out thanks to special probes and satellites for detecting the coordinates of radioactive belts, orbits are compiled in accordance with them to reduce the effect on the crew.
What natural radiation background is suitable for humans
Each region has its own background radiation, but for the population it is considered safe a value of approximately 0.5 microsievert per hour.The most suitable safe level for the human body is below 0.2 microsievert, the same amount has a natural background radiation. The norm in terms of radioactivity and its effect on humans for different situations is different. In all situations, a separation is made between personnel, that is, citizens whose work is related to radioactivity, the nuclear industry, and the general population. There are certain standards for premises and employees.
Device types
There are special tools for determining the content of radionuclides and the level of radiation:
- Spectrometric paths are used to determine the type of radionuclide and its level in the environment; they consist of a personal computer, an analyzer and a radiation detector.
- Different types of dosimeters are designed to determine the density of the neural stream, the x-ray power, the dose of gamma radiation.
Dosimeter
Today, there are many dosimeters for various purposes, such as those with extensive capabilities. Geophysical professional radiometers are ideal equipment for performing radiation measurements. Household and semi-professional radiometers are also used, but it is worth noting that in this case the quality of the information received is lower. To some extent, this can be compensated by the simultaneous use of two devices with a further combination of the results. Also, devices are divided into threshold and non-threshold.
Measurement
Before measuring the natural background radiation with a dosimeter, an approximate variation in the results of all the instruments used should be identified. This is the most important characteristic of the device, which must be taken into account when processing the results of work. This operation must be performed after transferring the measurement terrain and after a certain time.
The identification of averaged data is carried out as follows. The dosimeter is switched on and a series of measurements (about thirty) takes place in one place for a short time interval. Then the arithmetic mean is derived from the results. The calculated figures, which make up the difference between the device data and the averaged values, are taken with a positive sign and the average is detected again. The result of this averaging is the desired scatter of the device readings.
Measurement of the natural background radiation by the dosimeter in any place is performed at least 4-6 times, after which the arithmetic average value is displayed. When working with several devices, the final result is the average between the information received from each of the devices. In the event that measurements are made from many points, it is advisable to record the collected data in the form of a table.
Earth radiation
Responsibility for the natural background radiation from Earth is mainly attributed to three elements with radioactivity: sea anemone, thorium and uranium. They are notable for instability. The main source is radioactive particles that are present in the soil, formed after geophysical changes. Volcanoes and granite are leaders in the availability of these elements.
Isotopes
Over the course of evolution, radioisotopes move, taking part in geochemical and metrological changes. The natural radiation background is a multitude of associations of stable particles interacting with the body's metabolic processes. The more significant elements that affect the vital activity of matter, such as tritium and potassium isotopes, are much more particles in the biological sphere that determine the radioactivity of the body.
Planetary radiation has a variety of levels, depending on the presence of nuclides in a particular place of the crust.The radiation power in places inhabiting the majority of the population is most often 0.3-0.4 microsievert.
Sources of natural background radiation in a small cluster are present in the soil. It has an effect and its structure: the concentration is reduced in calcareous and sandy soil types, and increased in clay soil and granite rocks.
Radon
A person accounts for half of the individual annual equivalent effective dose of a complex gas of radon, invisible to the eye, odorless and tasteless. Basically, exposure to this gas is great in a stuffy room with closed windows, since there it has an increased concentration.
Radon seeps out of the earth's crust through the floor covering, holes in the foundation and most often gathers on the lower floors, forming an increased natural radiation background. Structural materials that can not be dispensed with in construction, which can also emit radon radiation, are also of importance. Such materials as gypsum containing phosphorus, alumina, and pumice are attributed to them to a greater extent.
The water used for food and domestic needs has mainly little gas, but deep-seated water layers may have a high content. A greater concentration is formed in the bathrooms, where gas penetrates with the surrounding oxygen into the body, released from hot water.
Increased radiation
The natural radiation background is partially changed by humanity in the process of improving technological processes, the production of various materials, and, accordingly, radiation increases. An example is the use of gas and coal, materials with an increased amount of nuclides, and flights on aircraft. The degrees of radiation noted in this case are called the increased technological background of the radioactive effect. People around the world are increasingly using for household needs a variety of devices, goods and objects that contain radionuclide particles. Optical specialized devices, holy watches, devices used during inspection at the customs border and at airports relate to such goods.
