Meet - it's radiation!
Radioactivity is one of the most unique and mysterious physical phenomena. Its amazing properties and possibilities have been the subject of study of several generations of physicists. The damage caused by radiation to mankind is extremely great. But its huge role in energy, medicine and natural science is also obvious.
To learn how to protect yourself from its harmful effects, we will become acquainted with the physical essence of this phenomenon and the corresponding terminology.
Types of radioactive emissions
The fundamental concept in this area is radioactivity, that is, the ability of the nuclei of some atoms to spontaneously decay (transform).
Radiation, what is it? This is ionizing radiation accompanying the process of radioactive decay and "floating" in space until it is absorbed by any substance.
Radiation radiation is not homogeneous. It consists of special particles and very short electromagnetic waves.
So, the types of radioactive emissions.
- Alpha particles that are nuclei of helium atoms. They are quite massive, carry a positive charge and, in spite of their low penetrating power, have a strong ionizing effect.
- Beta particles, which are ordinary electrons with a negative charge inherent in them.
- Gamma radiation - extremely short electromagnetic waves, which are very aggressive on the human body.
- Neutrons are very insidious particles that do not have an electric charge.
- X-rays are also of an electromagnetic nature, but with less penetrating power than gamma radiation.
Sources of radioactive 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;
- energy released during the decay of certain chemical elements, carefully preserved by nature in the earth's crust;
- man contains some radioactive elements (rubidium-87 and potassium-40), therefore, in itself is a source of personal radiation background.
The entire history of the formation of the Earth's biosphere occurs against the backdrop of natural radioactive radiation. Up to certain values it is not something unnatural for a person.
Nature, unfortunately, did not endow people with senses capable of responding to irradiation. However, there are physical quantities and units of their measurement, characterizing both the radiation itself and the degree of its effect on a person.
In what measure is the radiation measured? As a unit of measurement of the dose of ionizing radiation for a certain period of time, 1 x-ray is used. This is an extremely large dose of radiation, so in practice, use of its millionth part, called micro-radrogen (microR). The natural radiation background is normally 10-15 microroentgen per hour.
Artificial sources of radiation
Artificial sources of radiation arose as a result of technogenic activity of mankind:
- nuclear power plants;
- the place of extraction of minerals containing radioactive components;
- testing grounds;
- disposal of nuclear waste;
- military equipment with nuclear warheads;
- medical equipment using radioactive isotopes.
Application of radiation in medicine
A profound study of the properties of radioactive radiation made it possible to find the active application of radiation in medicine. There are three directions.
- Introduction of radioactive isotopes into the human body.
- Radiation therapy.
X-ray diagnostics uses a different penetrating ability of X-rays when passing through soft tissues and bones. The result of such a survey is fixed on a film or monitor screen.
Introduction of a small number of radioactive isotopes into the human body, allows for the fixation of their localization and concentration in a certain organ by radiation. Such diagnostics are extremely important for revealing a number of pathologies.
Radiation therapy is used to treat oncological diseases. The method is based on the fact that the radiation produced by the X-ray or gamma-ray device is sharply directed to the oncology focus and suppresses the ability of malignant cells to grow and multiply.
The listed methods of diagnostics and therapy make an additional contribution to the dose of radiation 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 occurs:
when extracting from the depths of the earth minerals on an industrial scale;
- in nuclear explosions;
- because of accidents at nuclear facilities and enterprises producing nuclear fuel;
- with active applications of mineral fertilizers, etc.
For example, in nuclear explosions, only 50% of nuclear fission products fall to the ground within a radius of about 100 km. The remaining 50% rush into the layers of the air shell very far from the Earth. Then they return to the earth for many months, dispersing over its surface within a radius of hundreds and thousands of kilometers in the form of natural and artificial radionuclides (radioactive varieties of chemical elements).
Thus, the plume of radiation and radioactive dust formed as a result of the Chernobyl explosion covered the vast part of the USSR, the Scandinavian countries and the whole of eastern Europe.
Radioactive decay is characterized by a chain of nuclear transformations: a radioactive atom that "disappears" as a result of this process, becomes a source of radiation and generates a new, no less dangerous radioactive element.
A huge contribution to the natural radiation background is made by radon gas. This heavy gas without taste and smell, bursting from the earth's interior, accumulates in the basement and lower floors of buildings. Its source is also water and natural gas.
There is a relationship between the altitude of the terrain above sea level, the geological structure of the earth's crust at this site and the intensity of the radiation background. This introduces its own corrections to the norm of the radiation background of a given area.
Certain radiation hazards are the buildings surrounding us and objects in them:
- the greater the age of construction, the higher the radiation level in it;
- The presence of a TV and a monitor with a conventional kinescope provides us with an additional share of radiation;
- a compass and a watch with phosphoric arrows, luminous telephone disks, sights - necessarily cause an increase in the general radiation background, although insignificant;
- any x-ray examination is also a source of radiation;
- A special danger is the internal irradiation that occurs when air, food and water hit the human body, affected by radiation.
Norm of radioactive radiation
To assess the state of the total radiation background, it is sufficient for a person to know the magnitude and the dose rate of radiation.
Radiation power is the dose value obtained by any object in a unit of time, measured in microR / hour. The permissible rate of radiation for a person is 25-30 microR / h.
If the received dose of radioactive irradiation fits within this framework, then the person simply does not notice it, and there is no negative effect on the state of health. If the permissible norm of irradiation received in a short period of time is repeatedly exceeded, symptoms of radiation sickness appear.
All the radiation that affects a person leaves a mark on his body. There is its accumulation, and the resulting consequences can have a variety of manifestations. Their nature depends on the accumulated dose and the time of its accumulation.
There is a concept of a lethal dose of radiation, under the influence of which a person dies directly during irradiation or in a few days. In this interval doses from 700 roentgens and above are included.
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 extra-background radiation sources affecting a person increase the rate of dose accumulation, which leads to a disruption of the normal vital activity of cells. Adapting the body to radiation does not happen!