Meet - this is radiation!
Radioactivity is one of the most unique and mysterious physical phenomena. Its amazing properties and capabilities have been the subject of several generations of physicists. The harm caused by radiation to humanity is extremely great. But its huge role is also evident when used in the energy, medicine and natural sciences.
To find out how to defend oneself from its harmful effects, let us get acquainted with the physical essence of this phenomenon and the corresponding terminology.
Types of radioactive radiation
Fundamental concept in this area is radioactivity, that is, the ability of the nuclei of some atoms to spontaneous decay (transformation).
Radiation, what is it? This is ionizing radiation that accompanies the process of radioactive decay and "soaring" in space until it is absorbed by any substance.
Radiation radiation is heterogeneous. It consists of special particles and very short electromagnetic waves.
So, the types of radioactive radiation.
- Alpha particles that are the nuclei of helium atoms. They are quite massive, have a positive charge and, despite the small penetrating ability, have a strong ionizing effect.
- Beta particles, which are ordinary electrons with their own negative charge.
- Gamma-radiation - extremely short electromagnetic waves, very aggressively affecting the human body.
- Neutrons are highly insidious particles that do not have an electric charge.
- X-rays are also of an electromagnetic nature, but with less penetration than gamma radiation.
Sources of radiation
What are the sources of radiation? They are divided into natural and artificial.
Natural sources of radiation
Natural sources of radiation include:
soil, water and atmosphere;
- space objects and, of course, the sun;
- the energy released during the decay of some chemical elements, carefully kept by Nature in the crust;
- a person contains some radioactive elements (rubidium-87 and potassium-40), therefore, in itself is a source of personal radiation background.
The whole history of the formation of the Earth's biosphere occurs against the background of natural radioactive radiation. To certain values, it is not unnatural for man.
Nature, unfortunately, did not endow people with sense organs capable of reacting to radiation. However, there are physical quantities and their units of measurement that characterize both the radiation itself and the degree of its effect on a person.
What is the radiation measured? As a unit for measuring the dose of ionizing radiation for a certain period of time, use 1 x-ray. This is an extremely large dose of radiation, so in practice it is used in a millionth part, called micro-roentgen (μR). The natural background radiation is normally 10–15 micro X-rays per hour.
Artificial radiation sources
Artificial sources of radiation have arisen as a result of man-made human activity:
- nuclear power plants;
- mining sites containing radioactive components;
- nuclear test sites;
- nuclear waste disposal;
- military equipment with nuclear warheads;
- medical equipment using radioactive isotopes.
The use of radiation in medicine
A deep study of the properties of radioactive radiation allowed us to find an active use of radiation in medicine. Here there are three directions.
- Introduction of radioactive isotopes into the human body.
- Radiation therapy.
In X-ray diagnostics, different penetrating power of X-rays is used when passing through soft tissues and bones. The result of such an examination is recorded on photographic film or a monitor screen.
Introduction to the human body of a small amount of radioactive isotopes, allows radiation to fix their localization and concentration in a particular organ. Such a diagnosis is extremely important to identify a number of pathologies.
For the treatment of cancer, radiation therapy is used. The method is based on the fact that the radiation generated by an X-ray or gamma-ray plant, has a sharply directed effect on the site of oncology and suppresses the ability of malignant cells to grow and multiply.
The listed methods of diagnostics and therapy make an additional contribution to the radiation dose received by a person.
Sources of radiation hazard
In recent decades there has been an increase in radiation from artificial sources, which causes serious concern and concern. The occurrence of such situations takes place:
when extracting from the bowels of the earth minerals on an industrial scale;
- nuclear explosions;
- due to accidents at nuclear facilities and enterprises producing nuclear fuel;
- with active applications of mineral fertilizers, etc.
For example, during nuclear explosions, only 50% of nuclear fission products fall to the ground within a radius of about 100 km. The remaining 50% rush into very remote from the earth layers of the air envelope. Then they return to the earth for many months, scattering over its surface within a radius of hundreds and thousands of kilometers in the form of natural and artificial radionuclides (radioactive species of chemical elements).
Thus, the plume of radiation and radioactive dust formed as a result of the Chernobyl explosion covered a large part of the USSR, the Scandinavian countries and the whole of Eastern Europe.
A chain of nuclear transformations is characteristic of radioactive decay: a radioactive atom “disappearing” as a result of this process, becomes a source of radiation and gives rise to a new, no less dangerous radioactive element.
Radon gas makes a huge contribution to the natural radiation background. This heavy gas without taste and smell, breaking from the bowels of the earth, accumulates in the basements and lower floors of buildings. Its source is also water and natural gas.
There is a connection between the height of the terrain above sea level, the geological structure of the earth's crust in this place and the intensity of the radiation background. This makes its own adjustments to the normal radiation background of the area.
Certain radiation hazards are the buildings around us and the objects in them:
- the greater the age of the building, the higher the level of radiation in it;
- the presence of a TV and a monitor with a conventional kinescope provides us with an additional fraction of radiation;
- a compass and a watch with phosphoric hands, luminous phone dials, and sights - necessarily cause an increase in the total background radiation, albeit a slight one;
- any X-ray examination is also a source of radiation;
- Of particular danger is the internal exposure that occurs when air is ingested, food and water are affected by radiation.
Norm of radioactive radiation
To assess the state of the general radiation background, it is enough for a person to know the magnitude and rate of radiation dose.
The radiation power is the amount of dose received by any object per unit of time, measured in μR / hour. Acceptable radiation rate for humans is 25-30 μR / h.
If the received dose of radiation exposure falls within this framework, then the person simply does not notice it, and no negative influence on the state of health occurs. With multiple exceeding the permissible rate of exposure received in a short period of time, symptoms of radiation sickness appear.
All radiation affecting a person leaves its mark on his body. It accumulates, and the resulting effects can have a variety of manifestations. Their character depends on the accumulated dose and the time of its accumulation.
There is the concept of a lethal dose of radiation, under the influence of which a person dies directly during irradiation or after a few days. In this interval included doses from 700 x-ray and above.
Why radiation can lead to tragic consequences? Since radiation is ionizing radiation, its effect leads to ionization of cells of living tissues. This causes their mutation and death.
Any off-background sources of radiation affecting a person increase the rate of dose accumulation, leading to disruption of the normal functioning of the cells. Adaptation of the body to radiation - does not occur!