Radiation does not exist. How radiation affects the body, immediate and long-term effects

Scientists studying the effect of radiation on living organisms are seriously concerned about its widespread. As one of the researchers said, modern humanity bathed in an ocean of radiation. Invisible to the eye, radioactive particles are found in soil and air, water and food, children's toys, body jewelry, building materials, and antiques. The most harmless at first glance, the subject can be hazardous to health.

Our body can also be called radioactive to a small extent. Its tissues always contain the chemical elements it needs - potassium, rubidium and their isotopes. It's hard to believe, but every second thousands of radioactive decays occur in us!

What is the meaning of radiation?

The atomic nucleus is made up of protons and neutrons. Their layout for some elements may be, to put it simply, not entirely successful, which is why they become unstable. Such nuclei have excess energy, which they seek to get rid of. You can do this in the following ways:

• Small "pieces" of two protons and two neutrons are ejected (alpha decay).
• In the nucleus, a proton turns into a neutron, and vice versa. In this case, beta particles are ejected, which are electrons or their twins with the opposite sign - antielectrons.
• Excess energy is released from the nucleus in the form of an electromagnetic wave (gamma decay).

In addition, the nucleus can emit protons, neutrons and completely fall apart into pieces. Thus, regardless of the type and origin, any type of radiation is a high-energy stream of particles with great speed(tens and hundreds of thousands of kilometers per second). It has a very detrimental effect on the body.

Effects of radiation on the human body

In our body, two opposite processes are continuously ongoing - cell death and cell regeneration. Under normal conditions, radioactive particles damage up to 8 thousand different compounds in DNA molecules per hour, which the body then independently restores. Therefore, doctors believe that small doses of radiation activate the body's biological defense system. But the big ones destroy and kill.

So, radiation sickness begins already when receiving 1-2 Sv, when doctors fix its 1st degree. In this case, observation, regular follow-up examinations for oncological diseases are necessary. A dose of 2-4 Sv means already the 2nd degree of radiation sickness, which requires treatment. If help arrives on time, there will be no death. A lethal dose is considered to be from 6 Sv, when even after bone marrow transplantation, only a 10th part of patients can be saved.

Without a dosimeter, a person will never understand that he is exposed to dangerous radiation. At first, the body does not react to it in any way. Only after a while nausea may appear, headaches, weakness begin, the temperature rises.

At high doses of radiation, radiation primarily affects the hematopoietic system. There are almost no lymphocytes left in it, the number of which depends on the level of immunity. Along with this, the number of chromosomal breakdowns (dicentrics) in cells increases.

On average, the human body should not be exposed to radiation doses greater than 1 mlSv per year. At exposure to 17 Sv, the probability of developing incurable cancer approaches its maximum value.

Learn more about how radiation affects the human body

Damage to cell atoms. The process of exposure to radiation on the body is called irradiation. This is extremely destructive force, which transforms cells, deforms their DNA, leads to mutations and genetic damage. destructive process can launch just one particle of radiation.

Experts compare the effect of ionizing radiation with snowball. It all starts small, then the process grows until irreversible changes occur. At the atomic level, this is how it works. Radioactive particles fly at great speed, knocking out electrons from atoms. As a result, the latter acquire a positive charge. The "black" case of radiation consists only in this. But the consequences of such transformations are catastrophic.

A free electron and an ionized atom enter into complex reactions resulting in the formation of free radicals. For example, water (H 2 O), which makes up 80% of a person's mass, under the influence of radiation breaks down into two radicals - H and OH. These pathologically active particles react with important biological compounds - DNA molecules, proteins, enzymes, fats. As a result, the number of damaged molecules and toxins in the body increases, and cell metabolism suffers. After some time, the affected cells die or their functions are seriously impaired.

What happens to the irradiated organism. Due to DNA damage and gene mutation, the cell cannot divide normally. This is the most dangerous consequence of radiation exposure. When receiving a large dose, the number of affected cells is so large that organs and systems may fail. Tissues in which active cell division occurs are the most difficult to perceive radiation:

• Bone marrow;
• lungs,
• gastric mucosa,
• intestines,
• sexual organs.

And even weakly radioactive item Prolonged contact is harmful to the human body. So, your favorite pendant or camera lens can become a time bomb for you.

The great danger of the influence of radiation on living organisms is that for a long time it does not manifest itself in any way. The "enemy" penetrates through the lungs, gastrointestinal tract, skin, and the person does not even know about it.

Depending on the degree and nature of exposure, its result is:

• acute radiation sickness;
• disruption of the central nervous system;
• local radiation injuries (burns);
• malignant neoplasms;
• leukemia;
• immune diseases;
• infertility;
• mutations.

Unfortunately, nature did not provide for human sense organs that could give him danger signals when approaching a radioactive source. Protect yourself from such a "sabotage" without always present at hand household dosimeter impossible.

How to protect yourself from excessive doses of radiation?

From external sources easier to defend. Alpha particles will be delayed by an ordinary cardboard sheet. Beta radiation does not penetrate glass. A thick lead sheet or a concrete wall can “cover” from gamma rays.

Worst of all is the case with internal exposure, in which the source is inside the body, having got there, for example, after inhaling radioactive dust or having dinner with mushrooms “seasoned” with cesium. In this case, the consequences of exposure are much more serious.

The most best protection from household ionizing radiation - timely detection of its sources. This will help you household dosimeters RADEX. With such devices at hand, life is much calmer: at any moment you are examining anything for radiation contamination.

Recently, terrible news arrived from the Land of the Rising Sun on the wings of a radiation cloud: there is a new leak at Fukushima that even robots cannot patch. In two hours they fail, to say nothing of people.

After such statements, one wants to put on a zinc suit and go somewhere where there is no radiation. But it is everywhere - this is how the cosmos works, a person has nothing to do with it at all. We know a lot about radiation: we know that it causes mutations, kills, and this, in general, our knowledge ends. But the more you know about it, the calmer you live.

1. Everything comes from space

Culture and Chernobyl taught us to panic at the mere mention of the word "radiation". But it's like being afraid of your skin or liquids, since radiation is all around us. She is among us, she is inseparable from us. Every day you come into contact with radioactive, and it's not at all about nuclear power plants, nuclear submarines and modern gadgets. We just live in a radioactive environment. 85% of the annual dose of radiation is the so-called natural radiation. Part of it is formed due to cosmic radiation. But throughout history, there were no idiots walking around with lead umbrellas, but there are people who live for more than a hundred years and do not get sick. If it comes to that, then the strongest release of radiation in history occurred in 2004, and neither Chernobyl nor Fukushima have nothing to do with it. Blame the neutron star, located 50 thousand light years from our planet.
Why, in the next few thousand years, the WR 104 binary star system should turn into a supernova. This release of radiation may or may not cause a mass extinction on Earth. In any case, you need to be afraid of just such doses.

2. Radiation - life?

Scientific facts show that the higher up the mountain, the more cosmic radiation the body is exposed to. That is, we get less protection from harmful radiation when we rise further and further from the earth. It would seem that everything is very bad, but despite high level radiation, science has identified one interesting feature: In mountainous areas, life expectancy is much higher. What is the reason - it is difficult to say, maybe radiation is the reason for their excellent health. Unfortunately, there is no clear answer. But recently another plus was discovered in the piggy bank of radiation. It turns out that radioactive iodine is able to detect and destroy the cells of a diseased thyroid gland in the body, even if they have managed to hit other organs. That is, in the future, radiation can be used in the treatment of hated cancer.

3. Not so good

However, not everything is so smooth. At the dawn of the era of radiation, it was used both in the tail and in the mane, even in medicine. For example, a quack doctor sold radium-irradiated water, which was advertised as a cure for arthritis, rheumatism, mental illness, stomach cancer and impotence. As a result, the creator himself suffered from his offspring: from radium water, the jaw and teeth of the unfortunate businessman literally fell apart.

In addition, radiation can make a man sterile, like the Witcher. Different human organs react to radioactive radiation in different ways. But, as it turned out, the sex cells are the most vulnerable -. Before sending their astronauts to the moon, American scientists tested the miraculous effects of radiation on 63 prisoners. Someone was more fortunate, and they simply became sterile impotent, while someone had more serious diseases, with lethal outcome

4. Your home is your source

You receive the largest dose of radiation right now, sitting at home, because cement, sand and gravel contain natural radionuclides. Therefore, these building materials are divided by legislation into classes depending on their "radioactivity". Before putting the house into operation, an inspection is carried out to find out whether safe materials were used in its construction. But how thorough and incorruptible she is is hard to say.

5. Not all problems from nuclear power plants

So for close contact with radiation it is not at all necessary to go to work at a nuclear power plant or go into space without a spacesuit. It is enough just to go to work in civil aviation and get a decent dose of radiation. Therefore, they are officially classified as "working in radiation conditions" - after all, proximity to space makes itself felt. That is, flying under the dome of heaven, we receive a background dose that exceeds the daily dose by 4 times.

This is even more than after a chest x-ray, although many refer to this procedure as a kind of suicide.

And since we are talking about professions, people living near coal-fired power plants receive a larger dose of radiation than those who live near nuclear power plants. It's just that there are a lot of radioactive isotopes in coal, as, in fact, in cigarette smoke.

6. Dangerous stone

But if radiation were so dangerous, then, probably, everyone who climbs granite steps descends into Moscow Metro or walking along the granite embankment of St. Petersburg, dying of radiation sickness, since the level of radiation in this stone exceeds even the norms allowed at nuclear power plants. But so far, no one's eyes have burned out, their hair has not fallen out, and the mucous membrane has not left in layers.

7. Radioactive food

The Brazil nut is not only one of the most expensive, but also one of the most radioactive foods in the world. Experts have found that after eating even a small portion of Brazil nuts, human urine and feces become extremely radioactive.

And all from the fact that the roots of the nut go so deep into the ground that they absorb a huge amount of radium, which is a natural source of radiation.

No better than nuts and bananas. They also produce a large amount of radiation, with the only difference being that in bananas, the radioactivity is present in their genetic code initially. But do not panic, put on a jumpsuit and go bury it to hell. For you to have even the slightest symptoms of radiation sickness, you need to eat at least 5 million fruits. So there is no need to panic when someone once again says that a handful of uranium is almost as radioactive as 10 bananas.

8. It's not contagious

As a result of all this, a reasonable question arises: is it possible to contact exposed people at all? You never know how life will turn out, suddenly another nuclear power plant will be covered with a copper basin.

Contrary to what many people think, radiation is not contagious. With patients suffering from radiation sickness and other diseases caused by exposure to radiation, you can communicate openly, without personal protective equipment. That is, the person himself, exposed to radiation, does not become an automatic emitter of radioactive substances. But his clothes, stained with radioactive materials (liquid, dust), create some danger to others. A source of radiation can only be called a patient in whose body there are radioactive drugs administered by doctors. But they quickly disintegrate, so there is no serious danger in this case.

In the very broad sense the words, radiation(lat. "shine", "radiation") is the process of propagation of energy in space in the form of various waves and particles. These include: infrared (thermal), ultraviolet, visible light radiation, as well as various types of ionizing radiation. Most Interest from the point of view of health and life safety is ionizing radiation, i.e. types of radiation capable of causing ionization of the substance on which they act. In particular, in living cells, ionizing radiation causes the formation of free radicals, the accumulation of which leads to the destruction of proteins, death or degeneration of cells, and, as a result, can cause the death of a macroorganism (animals, plants, humans). That is why, in most cases, the term radiation is used to mean precisely ionizing radiation. It is also worth understanding the differences between terms such as radiation and radioactivity. If the first can be applied to ionizing radiation located in free space, which will exist until it is absorbed by some object (substance), then radioactivity is the ability of substances and objects to emit ionizing radiation, i.e. be a source of radiation. Depending on the nature of the object and its origin, the terms are divided: natural radioactivity and artificial radioactivity. natural radioactivity accompanies the spontaneous decay of the nuclei of matter in nature and is characteristic of the "heavy" elements of the periodic table (with serial number over 82). artificial radioactivity is initiated by a person purposefully with the help of various nuclear reactions. In addition, it is worth highlighting the so-called "induced" radioactivity when some substance, object or even organism after strong impact ionizing radiation itself becomes a source of dangerous radiation due to the destabilization of atomic nuclei. A powerful source of radiation that is dangerous to human life and health can be any radioactive substance or object. Unlike many other hazards, radiation is invisible without special instruments, which makes it all the more frightening. The reason for the radioactivity of a substance is the unstable nuclei that make up the atoms, which, during decay, are released into environment invisible radiation or particles. Depending on various properties (composition, penetrating power, energy), today there are many types of ionizing radiation, of which the most significant and common are: alpha radiation. The source of radiation in it are particles with a positive charge and a relatively large weight. Alpha particles (2 protons + 2 neutrons) are quite bulky and therefore are easily retained by even minor obstacles: clothing, wallpaper, window curtains, etc. Even if alpha radiation hits a naked person, there is nothing to worry about, it will not pass beyond the surface layers of the skin. However, despite the low penetrating power, alpha radiation has a powerful ionization, which is especially dangerous if the source substances of alpha particles enter the human body directly, for example, into the lungs or digestive tract. . beta radiation. It is a stream of charged particles (positrons or electrons). Such radiation has a greater penetrating power than alpha particles; a wooden door, window glass, car body, etc. can delay it. It is dangerous for a person when exposed to unprotected skin, as well as when radioactive substances get inside. . Gamma radiation and nearby X-rays. Another type of ionizing radiation, which is related to the light flux, but with best ability to penetrate the surroundings. By its nature, it is high-energy short-wave electromagnetic radiation. In order to delay gamma radiation in some cases, a wall of several meters of lead, or several tens of meters of dense reinforced concrete, may be required. For humans, such radiation is the most dangerous. The main source of this type of radiation in nature is the Sun, however, the deadly rays do not reach humans due to the protective layer of the atmosphere.

Scheme of radiation generation various types Natural radiation and radioactivity In the environment around us, regardless of whether it is urban or rural, there are natural sources of radiation. Usually ionizing radiation natural origin rarely poses a danger to humans, its values ​​are usually within the acceptable range. natural radioactivity possesses soil, water, atmosphere, some products and things, many space objects. The primary source of natural radiation in many cases is the radiation of the Sun and the decay energy of some elements of the earth's crust. Even man himself possesses natural radioactivity. In the body of each of us there are substances such as rubidium-87 and potassium-40, which create a personal radiation background. The source of radiation can be a building, building materials, household items, which include substances with unstable atomic nuclei. It is worth noting that natural level radiation is not the same everywhere. So in some cities located high in the mountains, the level of radiation exceeds that at the height of the world's oceans by almost five times. There are also zones of the earth's surface where the radiation is significantly higher due to the location of radioactive substances in the bowels of the earth. Artificial radiation and radioactivity Unlike natural, artificial radioactivity is a consequence human activity. Sources of artificial radiation are: nuclear power plants, military and civilian equipment using nuclear reactors, mining sites with unstable atomic nuclei, nuclear test areas, nuclear fuel disposal and leakage sites, nuclear waste cemeteries, some diagnostic and therapeutic equipment, as well as radioactive isotopes in medicine.
How to detect radiation and radioactivity? The only way available to an ordinary person to determine the level of radiation and radioactivity is to use a special device - a dosimeter (radiometer). The principle of measurement is to register and estimate the number of radiation particles using a Geiger-Muller counter. Personal dosimeter No one is safe from the effects of radiation. Unfortunately, any object around us can be a source of lethal radiation: money, food, tools, building materials, clothing, furniture, vehicles, land, water, etc. In moderate doses, our body is able to tolerate the effects of radiation without harmful consequences, but today few people pay sufficient attention to radiation safety, exposing themselves and their families to mortal risk every day. Why is radiation dangerous for humans? As you know, the effect of radiation on the human or animal body can be of two types: from the inside or from the outside. None of them adds health. Moreover, science knows that internal influence radiation substances are more dangerous than external. Most often, radioactive substances enter our body along with contaminated water and food. In order to avoid internal exposure to radiation, it is enough to know what foods are its source. But with external radiation exposure, everything is a little different. Sources of radiation The radiation background is classified into natural and man-made. It is almost impossible to avoid natural radiation on our planet, since its sources are the Sun and the underground gas radon. This type of radiation practically does not have a negative impact on the body of people and animals, since its level on the Earth's surface is within the MPC. True, in space or even at an altitude of 10 km on board an airliner solar radiation can be a real danger. Thus, radiation and man are in constant interaction. With man-made sources of radiation, everything is ambiguous. In some areas of industry and mining, workers wear special protective clothing against exposure to radiation. The level of background radiation at such facilities can be much higher than the permissible norms.
Living in the modern world, it is important to know what radiation is and how it affects people, animals and vegetation. The degree of exposure to radiation on the human body is usually measured in Sievertach(abbreviated Sv, 1 Sv = 1000 mSv = 1000000 µSv). This is done with the help of special devices for measuring radiation - dosimeters. Under the influence of natural radiation, each of us is exposed to 2.4 mSv per year, and we do not feel this, since this indicator is absolutely safe for health. But at high doses of radiation, the consequences for the human or animal body can be the most severe. Of the well-known diseases that arise as a result of irradiation of the human body, such as leukemia, radiation sickness with all the ensuing consequences, all kinds of tumors, cataracts, infections, and infertility are noted. And with strong exposure, radiation can even cause burns! An approximate picture of the effects of radiation at various doses is as follows: . at an effective body irradiation dose of 1 Sv, the blood composition deteriorates; . at a dose of effective irradiation of the body of 2-5 Sv, alopecia and leukemia occur (the so-called "radiation sickness"); . at an effective body dose of 3 Sv, about 50 percent of people die within one month. That is, radiation at a certain level of exposure is an extremely serious danger to all living things. There is also a lot of talk about the fact that radiation exposure leads to mutation at the gene level. Some scientists consider radiation to be the main cause of mutations, while others argue that the transformation of genes is not at all associated with exposure to ionizing radiation. In any case, the question of the mutagenic effect of radiation is still open. But there are a lot of examples of the fact that radiation causes infertility. Is radiation contagious? Is it dangerous to contact exposed people? Contrary to what many people think, radiation is not contagious. With patients suffering from radiation sickness and other diseases caused by exposure to radiation, you can communicate without personal protective equipment. But only if they did not come into direct contact with radioactive substances and are not sources of radiation themselves! For whom is radiation most dangerous? Most strong influence radiation affects the younger generation, that is, children. Scientifically, this is explained by the fact that ionizing radiation has a stronger effect on cells that are in the stage of growth and division. Adults are much less affected, as their cell division slows down or stops. But pregnant women need to be wary of radiation at all costs! At the stage of intrauterine development, the cells of the growing organism are especially sensitive to radiation, so even a slight and short-term exposure to radiation can have an extremely negative impact on the development of the fetus. How to recognize radiation? It is almost impossible to detect radiation without special instruments before health problems appear. This is the main danger of radiation - it is invisible! The modern market of goods (food and non-food) is controlled by special services that check the compliance of products with established radiation emission standards. Nevertheless, the probability of acquiring a thing or even a food product, the radiation background of which does not meet the standards, still exists. Usually such goods are brought from the infected territories illegally. Do you want to feed your child foods containing radioactive substances? Obviously not. Then buy products only in trusted places. Better yet, buy a device that measures radiation, and use it to your health!
How to deal with radiation? The simplest and most obvious answer to the question "How to remove radiation from the body?" is the following: go to the gym! Physical activity leads to increased sweating, and radiation substances are excreted along with sweat. You can also reduce the effect of radiation on the human body if you visit the sauna. It has almost the same effect as physical exercise- leads to increased sweating. The consumption of fresh vegetables and fruits can also reduce the impact of radiation on human health. You need to know that to date, the ideal means of protection against radiation has not yet been invented. The easiest and most effective way to protect yourself from the negative effects of deadly rays is to stay away from their source. If you know everything about radiation and know how to use the instruments to measure it correctly, you can almost completely avoid its negative impact. What can be the source of radiation? We have already said that it is almost impossible to completely protect yourself from the effects of radiation on our planet. Each of us is constantly under the influence radioactive radiation, natural and man-made. Anything can be a source of radiation, from a seemingly harmless children's toy to a nearby enterprise. However, these objects can be considered temporary sources of radiation that can be protected from. In addition to them, there is also a general background radiation created by several sources that surround us at once. Background ionizing radiation can create gaseous, solid and liquid substances for various purposes. For example, the most massive gaseous source of natural radiation is radon gas. It is constantly emitted in small quantities from the bowels of the Earth and accumulates in basements, lowlands, on the lower floors of premises, etc. Even the walls of the premises cannot completely protect against radioactive gas. Moreover, in some cases, the walls of buildings themselves can be a source of radiation. Radiation environment in the premises Radiation in the premises, created by the building materials from which the walls are built, can pose a serious threat to the life and health of people. To assess the quality of premises and buildings in terms of radioactivity, special services have been organized in our country. Their task is to periodically measure the level of radiation in houses and public buildings and compare the results with existing standards. If the level of radiation from building materials in the room is within these limits, then the commission approves its further operation. Otherwise, the building may be ordered to repair, and in some cases, demolition with subsequent disposal of building materials. It should be noted that almost any structure creates a certain radiation background. Moreover, the older the building, the higher the level of radiation in it. With this in mind, when measuring the level of radiation in a building, its age is also taken into account.
Enterprises - technogenic sources of radiation household radiation There is a category of household items that emit radiation, although within acceptable limits. This is, for example, a watch or a compass, the hands of which are coated with radium salts, due to which they glow in the dark (a familiar phosphor glow). It is also safe to say that there is radiation in the room where a TV or monitor based on a conventional CRT is installed. For the sake of the experiment, the experts brought the dosimeter to a compass with phosphoric needles. We got a slight excess of the general background, however, within the normal range.
Radiation and medicine A person is exposed to radioactive irradiation at all stages of his life, working on industrial enterprises while at home and even undergoing treatment. A classic example of the use of radiation in medicine is FLG. According to the current rules, everyone must undergo fluorography at least once a year. During this examination procedure, we are exposed to radiation, but the radiation dose in such cases is within the safety limits.
Infected products It is considered that the most dangerous source radiation that can be encountered in everyday life are food, which is a source of radiation. Few people know where it was brought from, for example, potatoes or other fruits and vegetables, from which the shelves of grocery stores are now literally bursting. But it is these goods that can pose a serious threat to human health, storing radioactive isotopes in their composition. Radiation food is stronger than other sources of radiation affects the body, as it gets directly into it. Thus, a certain dose of radiation emits most of the objects and substances. Another thing is what is the magnitude of this radiation dose: is it dangerous for health or not. It is possible to assess the danger of certain substances from a radiation point of view using a dosimeter. As you know, in small doses, radiation has practically no effect on health. Everything that surrounds us creates a natural radiation background: plants, earth, water, soil, sun rays. But this does not mean at all that ionizing radiation should not be feared at all. Radiation is only safe when it is normal. So what are the safe rules? Standards for general radiation safety of premises From the point of view of the radiation background, the premises are considered safe if the content of thorium and radon particles in them does not exceed 100 Bq per cubic meter. In addition, radiation safety can be assessed by the difference between the effective dose of radiation in the room and outside it. It should not go beyond 0.3 µSv per hour. Such measurements can be carried out by anyone - for this it is enough to buy a personal dosimeter. The level of radiation background in the premises is strongly influenced by the quality of materials used in the construction and repair of buildings. That is why, before carrying out construction work, special sanitary services perform appropriate measurements of the content of radionuclides in building materials (for example, they determine the specific effective activity of radionuclides). Depending on the category of the object for which one or another building material is supposed to be used, allowable norms of specific activity vary over a fairly wide range. For building materials used in the construction of public and residential facilities ( I class) the effective specific activity should not exceed 370 Bq/kg. . For building materials II class, that is, industrial, as well as for the construction of roads in settlements the threshold of admissible specific activity of radionuclides should be at around 740 Bq/kg and below. . Roads outside built-up areas related to III class should be built using materials, the specific activity of radionuclides in which does not exceed 1.5 kBq/kg. . For the construction of facilities IV class materials with specific activity of radiation components not more than 4 kBq/kg can be used. The site specialists found out that today building materials with higher levels of radionuclides are not allowed to be used. What kind of water can you drink? The maximum permissible levels of radionuclides have also been established for drinking water. Water is allowed for drinking and cooking if the specific activity of alpha radionuclides in it does not exceed 0.1 Bq/kg, and that of beta radionuclides - 1 Bq/kg. Radiation Absorption Rates It is known that each object is capable of absorbing ionizing radiation, being in the zone of action of a radiation source. Man is no exception - our body absorbs radiation no worse than water or earth. In accordance with this, the standards for absorbed ion particles for humans have been developed: . For the general population, the permissible effective dose per year is 1 mSv (in accordance with this, the quantity and quality of diagnostic medical procedures that have a radiation effect on humans are limited). . For group A personnel, the average may be higher, but should not exceed 20 mSv per year. . For the working personnel of group B, the permissible effective annual dose of ionizing radiation should be on average no more than 5 mSv. There are also norms for the equivalent dose of radiation per year for individual organs of the human body: the lens of the eye (up to 150 mSv), skin (up to 500 mSv), hands, feet, etc. Norms of the general radiation situation Natural radiation is not standardized, since depending on the geographical location and time, this indicator can vary over a very wide range. For example, recent measurements of the radiation background on the streets of the Russian capital showed that the background level here is in the range from 8 to 12 microroentgens per hour. On mountain peaks, where the protective properties of the atmosphere are lower than in settlements located closer to the level of the world ocean, the indicators of ionizing radiation can be even 5 times higher than Moscow values! Also, the level of background radiation can be above average in places where the air is oversaturated with dust and sand with a high content of thorium and uranium. You can determine the quality of the conditions in which you live or are just going to settle in terms of radiation safety using a household dosimeter-radiometer. This small device can be powered by batteries and allows you to evaluate the radiation safety of building materials, fertilizers, food, which is important in the conditions of the already poor ecology in the world. Despite the high danger that almost any source of radiation carries, methods of protection against radiation still exist. All methods of protection against radiation exposure can be divided into three types: time, distance and special screens. time protection The meaning of this method of protection against radiation is to minimize the time spent near the radiation source. The less time a person is near a source of radiation, the less harm to health it will cause. This method protection was used, for example, in the liquidation of the accident at the nuclear power plant in Chernobyl. The liquidators of the consequences of the explosion at a nuclear power plant were given only a few minutes to do their job in the affected area and return to safe territory. Exceeding the time led to an increase in the level of exposure and could be the beginning of the development of radiation sickness and other consequences that radiation can cause. distance protection If you find an object near you that is a source of radiation - one that can pose a danger to life and health, you must move away from it at a distance where the radiation background and radiation are within acceptable limits. It is also possible to remove the source of radiation to a safe area or for disposal. Anti-radiation screens and overalls In some situations, it is simply necessary to carry out some kind of activity in an area with an increased background radiation. An example could be the elimination of the consequences of an accident at nuclear power plants or work at industrial enterprises where there are sources of radioactive radiation. Being in such areas without the use of personal protective equipment is dangerous not only for health, but also for life. Especially for such cases, personal protective equipment against radiation has been developed. They are screens made of materials that trap various types of radiation and special clothing. Protective suit against radiation What are radiation protection products made of? As you know, radiation is classified into several types depending on the nature and charge of the radiation particles. In order to withstand certain types of radiation, protective equipment against it is made using various materials: . Protect a person from radiation alpha, rubber gloves, a paper "barrier" or a regular respirator help.
. If the infected zone is dominated by beta radiation, then in order to protect the body from its harmful effects, you will need a screen made of glass, a thin aluminum sheet, or a material such as plexiglass. To protect against beta radiation of the respiratory system, a conventional respirator is no longer enough. Here you will need a gas mask.
. The hardest thing is to protect yourself from gamma radiation. Uniforms that have a shielding effect from this kind of radiation are made of lead, cast iron, steel, tungsten and other metals with a high mass. It was lead clothing that was used in the work on Chernobyl nuclear power plant after the crash.
. All kinds of barriers made of polymers, polyethylene and even water effectively protect against harmful effects neutron particles.
Food supplements against radiation Very often, food additives are used in conjunction with overalls and screens to provide protection against radiation. They are taken orally before or after entering an area with an increased level of radiation and in many cases can reduce the toxic effects of radionuclides on the body. In addition, certain foods can reduce the harmful effects of ionizing radiation. Eleutherococcus reduces the effect of radiation on the body 1) Food products that reduce the effect of radiation. Even nuts, white bread, wheat, radishes can reduce the effects of radiation exposure on humans to a small extent. The fact is that they contain selenium, which prevents the formation of tumors that can be caused by radiation exposure. Very good in the fight against radiation and dietary supplements based on algae (kelp, chlorella). Even onion and garlic can partially rid the body of the radioactive nuclides that have penetrated into it. ASD - a drug for protection against radiation 2) Pharmaceutical herbal preparations against radiation. Against radiation, the drug "Ginseng Root", which can be bought at any pharmacy, has an effective effect. It is used in two doses before meals in the amount of 40-50 drops at a time. Also, to reduce the concentration of radionuclides in the body, it is recommended to use Eleutherococcus extract in a volume of a quarter to a half teaspoon per day, along with tea drunk in the morning and at lunchtime. Leuzea, zamaniha, lungwort also belong to the category of radio-protective drugs, and they can be purchased at pharmacies.
Individual first aid kit with drugs to protect against radiation But, again, no drug can completely resist the effects of radiation. The best way to protect yourself from radiation is to not have contact with contaminated objects at all and not to be in places with an increased background radiation. Dosimeters are measuring instruments for numerical assessment of the dose of radioactive radiation or the rate of this dose per unit of time. The measurement is made using a built-in or separately connected Geiger-Muller counter: it measures the dose of radiation by counting the number of ionizing particles passing through its working chamber. It is this sensitive element that is the main part of any dosimeter. The data obtained during the measurements are converted and amplified by the electronics built into the dosimeter, and the readings are displayed on a pointer or numeric, more often a liquid crystal indicator. By the value of the dose of ionizing radiation, which is usually measured by household dosimeters in the range from 0.1 to 100 μSv / h (microsievert per hour), it is possible to assess the degree of radiation safety of a territory or object. To check substances (both liquid and solid) for compliance with radiation standards, a device is needed that allows the measurement of such a quantity as a micro-roentgen. Most modern dosimeters allow measuring this value in the range from 10 to 10,000 μR/h, which is why such devices are often called dosimeters-radiometers. Types of dosimeters All dosimeters are classified into professional and individual (for use in living conditions). The difference between them lies mainly in the limits of measurement and the magnitude of the error. Unlike household dosimeters, professional dosimeters have a wider measurement range (usually from 0.05 to 999 µSv/h), while personal dosimeters are mostly unable to determine doses greater than 100 µSv per hour. Also, professional devices differ from household ones in terms of error: for household, the measurement error can reach 30%, and for professional ones, it cannot be more than 7%.
A modern dosimeter can be carried with you everywhere! The functions of both professional and household dosimeters may include an audible alarm, which turns on at a certain threshold of the measured radiation dose. The value at which the alarm is triggered can be set by the user in some devices. This function makes it easy to find potentially dangerous items. Purpose of professional and household dosimeters: 1. Professional dosimeters are designed for use in industrial facilities, nuclear submarines and other similar places where there is a risk of getting high dose exposure (this explains why professional dosimeters generally have a wider measurement range). 2. Household dosimeters can be used by the population to assess the radiation background in an apartment or house. Also, with the help of such dosimeters, it is possible to check building materials for the level of radiation and the territory on which it is planned to build a building, to check the "purity" of purchased fruits, vegetables, berries, mushrooms, fertilizers, etc.
Compact professional dosimeter with two Geiger-Muller counters Household dosimeter has a small size and weight. Works, as a rule, from accumulators or batteries of food. You can take it with you everywhere, for example, when going to the forest for mushrooms or even to the grocery store. The radiometry function, which is available in almost all household dosimeters, allows you to quickly and efficiently assess the condition of products and their suitability for consumption. Dosimeters of the past years were inconvenient and cumbersome Almost everyone can buy a dosimeter today. Not so long ago, they were available only to special services, had a high cost and large dimensions, which greatly hampered their use by the population. Modern advances in the field of electronics have made it possible to significantly reduce the size of household dosimeters and make them more affordable. The updated devices soon gained worldwide recognition and today are the only effective solution to assess the dose of ionizing radiation. No one is immune from a collision with sources of radiation. You can find out that the level of radiation has been exceeded only by reading a dosimeter or by a special warning sign. Typically, such signs are installed near man-made sources of radiation: factories, nuclear power plants, radioactive waste disposal sites, etc. Of course, you will not find such signs in the market or in the store. But this does not mean at all that there can be no sources of radiation in such places. There are cases when food, fruits, vegetables and even medicines were the source of radiation. How radionuclides can end up in consumer goods is another question. The main thing is to know how to behave in case of detection of radiation sources. Where can I find a radioactive item? Since at industrial facilities of a certain category the probability of encountering a source of radiation and receiving a dose is especially high, dosimeters are issued here to almost all personnel. In addition, workers undergo a special training course in which they explain to people how to behave in the event of a radiation threat or when a dangerous object is detected. Also, many enterprises working with radioactive substances are equipped with light and sound alarms, when triggered, the entire staff of the enterprise is quickly evacuated. In general, industry workers are well aware of how to act in the event of a radiation threat. Things are quite different when sources of radiation are found in the home or on the street. Many of us simply do not know what to do in such situations and what to do. Warning label "radioactivity" How to behave when a source of radiation is detected? When detecting an object of radiation radiation, it is important to know how to behave so that the radiation find does not harm either you or others. Please note: if you have a dosimeter in your hands, this does not give you any right to try to eliminate the detected source of radiation on your own. The best thing you can do in such a situation is to move to a safe distance from the object and warn passers-by about the danger. All other work on the disposal of the object should be entrusted to the appropriate authorities, for example, the police. Relevant services are engaged in the search and disposal of radioactive items. We have already said more than once that a source of radiation can be detected even in a grocery store. In such situations, it is also impossible to remain silent or try to "deal" with the sellers on your own. It is better to politely warn the store administration and contact the Sanitary and Epidemiological Supervision Service. If you have not made a dangerous purchase, this does not mean that someone else will not buy a radiation item!

"People's attitude to this or that danger is determined by how well it is familiar to them."

This material is a generalized answer to numerous questions that arise from users of devices for detecting and measuring radiation in the home.
The minimal use of specific terminology of nuclear physics in the presentation of the material will help you to freely navigate this environmental problem, without succumbing to radiophobia, but also without excessive complacency.

The danger of RADIATION real and imaginary

"One of the first naturally occurring radioactive elements discovered was called 'radium'"
- translated from Latin - emitting rays, radiating.

Each person in the environment lies in wait for various phenomena that affect him. These include heat, cold, magnetic and ordinary storms, heavy rains, heavy snowfalls, strong winds, sounds, explosions, etc.

Due to the presence of the sense organs assigned to him by nature, he can quickly respond to these phenomena with the help of, for example, a sunshade, clothing, housing, medicines, screens, shelters, etc.

However, in nature there is a phenomenon to which a person, due to the lack of the necessary sense organs, cannot instantly react - this is radioactivity. Radioactivity is not a new phenomenon; radioactivity and its accompanying radiation (the so-called ionizing radiation) have always existed in the Universe. Radioactive materials are part of the Earth, and even a person is slightly radioactive, because. Every living tissue contains trace amounts of radioactive substances.

The most unpleasant property of radioactive (ionizing) radiation is its effect on the tissues of a living organism, therefore, appropriate measuring instruments are needed that would provide operational information for making useful decisions before a long time passes and undesirable or even fatal consequences appear. will not begin to feel immediately, but only after some time has passed. Therefore, information about the presence of radiation and its power must be obtained as early as possible.
But enough of the mysteries. Let's talk about what radiation and ionizing (i.e. radioactive) radiation are.

ionizing radiation

Any environment consists of the smallest neutral particles - atoms, which consist of positively charged nuclei and negatively charged electrons surrounding them. Each atom is like a miniature solar system: around a tiny nucleus, “planets” move in orbits - electrons.
atom nucleus consists of several elementary particles - protons and neutrons held by nuclear forces.

Protons particles that have a positive charge absolute value charge of electrons.

Neutrons neutral, uncharged particles. The number of electrons in an atom is exactly equal to the number of protons in the nucleus, so each atom is neutral as a whole. The mass of a proton is almost 2000 times the mass of an electron.

The number of neutral particles (neutrons) present in the nucleus can be different for the same number of protons. Such atoms, having nuclei with the same number of protons, but differing in the number of neutrons, are varieties of the same chemical element called "isotopes" of the element. To distinguish them from each other, a number equal to the sum of all particles in the nucleus of a given isotope is assigned to the element symbol. So uranium-238 contains 92 protons and 146 neutrons; Uranium 235 also has 92 protons, but 143 neutrons. All isotopes of a chemical element form a group of "nuclides". Some nuclides are stable, i.e. do not undergo any transformations, while others emitting particles are unstable and turn into other nuclides. As an example, let's take an atom of uranium - 238. From time to time, a compact group of four particles escapes from it: two protons and two neutrons - "alpha particle (alpha)". Uranium-238 is thus converted into an element whose nucleus contains 90 protons and 144 neutrons - thorium-234. But thorium-234 is also unstable: one of its neutrons turns into a proton, and thorium-234 turns into an element with 91 protons and 143 neutrons in its nucleus. This transformation also affects the electrons moving in their orbits (beta): one of them becomes, as it were, superfluous, without a pair (proton), so it leaves the atom. A chain of numerous transformations, accompanied by alpha or beta radiation, ends with a stable lead nuclide. Of course, there are many similar chains of spontaneous transformations (decays) of different nuclides. The half-life is the period of time during which the initial number of radioactive nuclei is on average halved.
With each act of decay, energy is released, which is transmitted in the form of radiation. Often an unstable nuclide is in an excited state, and the emission of a particle does not lead to a complete removal of the excitation; then he throws out a portion of energy in the form of gamma radiation (gamma quantum). As with X-rays (which differ from gamma rays only in frequency), no particles are emitted. The whole process of spontaneous decay of an unstable nuclide is called radioactive decay, and the nuclide itself is a radionuclide.

Various types of radiation are accompanied by the release different quantity energy and have different penetrating power; therefore, they have a different effect on the tissues of a living organism. Alpha radiation is delayed, for example, by a sheet of paper and is practically unable to penetrate the outer layer of the skin. Therefore, it does not pose a danger until radioactive substances emitting alpha particles enter the body through an open wound, with food, water or inhaled air or steam, for example, in a bath; then they become extremely dangerous. A beta particle has a greater penetrating power: it passes into the tissues of the body to a depth of one or two centimeters or more, depending on the amount of energy. The penetrating power of gamma radiation, which propagates at the speed of light, is very high: it can only be stopped by a thick lead or concrete slab. Ionizing radiation is characterized by a number of measured physical quantities. These include energy quantities. At first glance, it may seem that they are enough to register and evaluate the effects of ionizing radiation on living organisms and humans. However, these energy quantities do not reflect physiological impact ionizing radiation on the human body and other living tissues are subjective, and are different for different people. Therefore, average values ​​are used.

Sources of radiation are natural, present in nature, and not dependent on man.

It has been found that of all natural sources radiation, the greatest danger is radon - a heavy gas without taste, smell and at the same time invisible; with their child products.

Radon is released from the earth's crust everywhere, but its concentration in the outdoor air varies significantly for various points the globe. Paradoxical as it may seem at first glance, but a person receives the main radiation from radon while in a closed, unventilated room. Radon is concentrated in indoor air only when they are sufficiently isolated from the external environment. Seeping through the foundation and floor from the soil or, less often, being released from building materials, radon accumulates in the room. Sealing rooms for the purpose of insulation only exacerbates the matter, since it makes it even more difficult for the radioactive gas to escape from the room. The problem of radon is especially important for low-rise buildings with careful sealing of premises (in order to preserve heat) and the use of alumina as an additive to building materials(the so-called "Swedish problem"). The most common building materials - wood, brick and concrete - emit relatively little radon. Granite, pumice, products made from alumina raw materials, and phosphogypsum have much higher specific radioactivity.

Another, usually less important, source of indoor radon is water and natural gas used for cooking and home heating.

The concentration of radon in commonly used water is extremely low, but water from deep wells or artesian wells contain a lot of radon. However, the main danger does not come from drinking water, even with a high content of radon in it. Usually people consume most of the water in food and in the form of hot drinks, and when boiling water or cooking hot dishes, radon almost completely disappears. A much greater danger is the ingress of water vapor with a high content of radon into the lungs along with the inhaled air, which most often occurs in the bathroom or steam room (steam room).

In natural gas, radon penetrates underground. As a result of preliminary processing and during the storage of gas before it enters the consumer, most of the radon escapes, but the concentration of radon in the room can increase markedly if stoves and other gas heating appliances are not equipped with an exhaust hood. In the presence of supply and exhaust ventilation, which communicates with the outside air, the concentration of radon in these cases does not occur. This also applies to the house as a whole - focusing on the readings of radon detectors, you can set the ventilation mode of the premises, which completely eliminates the threat to health. However, given that the release of radon from the soil is seasonal, it is necessary to control the effectiveness of ventilation three to four times a year, not allowing the concentration of radon to exceed the norms.

Other sources of radiation, which unfortunately have a potential danger, are created by man himself. Sources of artificial radiation are artificial radionuclides, beams of neutrons and charged particles created with the help of nuclear reactors and accelerators. They are called man-made sources of ionizing radiation. It turned out that along with a dangerous character for a person, radiation can be put at the service of a person. Here is a far from complete list of areas of application of radiation: medicine, industry, agriculture, chemistry, science, etc. A calming factor is the controlled nature of all activities related to the production and use of artificial radiation.

In terms of their impact on humans, tests of nuclear weapons in the atmosphere, accidents at nuclear power plants and nuclear reactors and the results of their work, manifested in radioactive fallout and radioactive waste. However, only emergencies, such as the Chernobyl accident, can have an uncontrolled impact on humans.
The rest of the work is easily controlled at a professional level.

When radioactive fallout occurs in some areas of the Earth, radiation can enter the human body directly through agricultural products and food. Protecting yourself and your loved ones from this danger is very simple. When buying milk, vegetables, fruits, herbs, and any other products, it will not be superfluous to turn on the dosimeter and bring it to the purchased products. Radiation is not visible - but the device will instantly detect the presence of radioactive contamination. This is our life in the third millennium - the dosimeter becomes an attribute Everyday life like handkerchief, toothbrush, soap.

IMPACT OF IONIZING RADIATION ON TISSUES OF THE BODY

Damage caused in a living organism by ionizing radiation will be the greater, the more energy it transfers to tissues; the amount of this energy is called a dose, by analogy with any substance entering the body and completely absorbed by it. The body can receive a dose of radiation regardless of whether the radionuclide is outside the body or inside it.

The amount of radiation energy absorbed by the irradiated tissues of the body, calculated per unit mass, is called the absorbed dose and is measured in Grays. But this value does not take into account the fact that with the same absorbed dose, alpha radiation is much more dangerous (twenty times) than beta or gamma radiation. The dose recalculated in this way is called the equivalent dose; It is measured in units called Sieverts.

It should also be taken into account that some parts of the body are more sensitive than others: for example, at the same equivalent dose of radiation, the occurrence of cancer in the lungs is more likely than in the thyroid gland, and irradiation of the gonads is especially dangerous due to the risk of genetic damage. Therefore, human exposure doses should be taken into account with different coefficients. Multiplying the equivalent doses by the corresponding coefficients and summing up over all organs and tissues, we obtain the effective equivalent dose, which reflects the total effect of irradiation on the body; it is also measured in Sieverts.

charged particles.

Alpha and beta particles penetrating into the tissues of the body lose energy due to electrical interactions with the electrons of those atoms near which they pass. (Gamma radiation and X-rays transfer their energy to matter in several ways, which ultimately also lead to electrical interactions).

Electrical interactions.

In the order of ten trillionth of a second after the penetrating radiation reaches the corresponding atom in the tissue of the body, an electron is detached from this atom. The latter is negatively charged, so the rest of the initially neutral atom becomes positively charged. This process is called ionization. The detached electron can further ionize other atoms.

Physical and chemical changes.

Both a free electron and an ionized atom usually cannot stay in this state for a long time and for the next ten billionths of a second participate in complex chain reactions that produce new molecules, including extremely reactive ones such as "free radicals".

chemical changes.

Over the next millionths of a second, the free radicals formed react both with each other and with other molecules and, through a chain of reactions not yet fully understood, can cause chemical modification of biologically important molecules necessary for the normal functioning of the cell.

biological effects.

Biochemical changes can occur both in a few seconds and decades after irradiation and cause immediate cell death or changes in them.

RADIOACTIVITY UNITS
Becquerel (Bq, Vq); Curie (Ki, Si)	1 Bq = 1 disintegration per second. 1 Ki \u003d 3.7 x 10 10 Bq	Radionuclide activity units. Represent the number of decays per unit time.
Gray (Gr, Gu); Glad (rad, rad)	1 Gy = 1 J/kg 1 rad = 0.01 Gy	units of absorbed dose. Represent the amount of energy of ionizing radiation absorbed by a unit mass of any physical body such as body tissues.
Sievert (Sv, Sv) Rem (ber, rem) - "X-ray biological equivalent"	1 Sv = 1 Gy = 1 J/kg (for beta and gamma) 1 µSv = 1/1000000 Sv 1 ber = 0.01 Sv = 10 mSv Dose equivalent units.	Units of equivalent dose. They are a unit of absorbed dose multiplied by a factor that takes into account the unequal danger of different types of ionizing radiation.
Gray per hour (Gy/h); Sievert per hour (Sv/h); Roentgen per hour (R/h)	1 Gy/h = 1 Sv/h = 100 R/h (for beta and gamma) 1 µSv/h = 1 µGy/h = 100 µR/h 1 µR/h = 1/1000000 R/h	Dose rate units. Represent the dose received by the body per unit of time.

For information, and not for intimidation, especially people who decide to devote themselves to working with ionizing radiation, you should know the maximum allowable doses. The units of measurement of radioactivity are given in Table 1. According to the conclusion of the International Commission on Radiation Protection for 1990, harmful effects can occur at equivalent doses of at least 1.5 Sv (150 rem) received during the year, and in cases of short-term exposure - at doses above 0.5 Sv (50 rem). When exposure exceeds a certain threshold, radiation sickness occurs. There are chronic and acute (with a single massive impact) forms of this disease. Acute radiation sickness is divided into four degrees of severity, ranging from a dose of 1-2 Sv (100-200 rem, 1st degree) to a dose of more than 6 Sv (600 rem, 4th degree). The fourth degree can be fatal.

Doses received under normal conditions are negligible compared to those indicated. The equivalent dose rate generated by natural radiation ranges from 0.05 to 0.2 µSv/h, i.e. from 0.44 to 1.75 mSv/year (44-175 mrem/year).
In medical diagnostic procedures - X-rays, etc. - a person receives about 1.4 mSv/year.

Since radioactive elements are present in brick and concrete in small doses, the dose increases by another 1.5 mSv/year. Finally, due to the emissions of modern coal-fired thermal power plants and air travel, a person receives up to 4 mSv / year. The total existing background can reach 10 mSv/year, but on average does not exceed 5 mSv/year (0.5 rem/year).

Such doses are completely harmless to humans. The dose limit in addition to the existing background for a limited part of the population in areas of increased radiation is set at 5 mSv / year (0.5 rem / year), i.e. with a 300-fold margin. For personnel working with sources of ionizing radiation, the maximum allowable dose is 50 mSv/year (5 rem/year), i.e. 28 μSv/h for a 36-hour work week.

According to the hygienic standards NRB-96 (1996), the permissible dose rates for external exposure of the whole body from man-made sources for the permanent residence of personnel members are 10 μGy/h, for residential premises and areas where members of the public are permanently located - 0 .1 µGy/h (0.1 µSv/h, 10 µR/h).

WHAT IS RADIATION MEASURED

A few words about registration and dosimetry of ionizing radiation. Exist various methods registration and dosimetry: ionization (associated with the passage of ionizing radiation in gases), semiconductor (in which the gas is replaced solid), scintillation, luminescent, photographic. These methods form the basis of the work dosimeters radiation. Among the gas-filled sensors of ionizing radiation, one can note ionization chambers, fission chambers, proportional counters and Geiger-Muller counters. The latter are relatively simple, the cheapest, and not critical to the working conditions, which led to their widespread use in professional dosimetric equipment designed to detect and evaluate beta and gamma radiation. When the sensor is a Geiger-Muller counter, any ionizing particle entering the sensitive volume of the counter will cause self-discharge. Precisely falling into a sensitive volume! Therefore, alpha particles are not registered, because they can't get in there. Even when registering beta - particles, it is necessary to bring the detector closer to the object to make sure that there is no radiation, because. in the air, the energy of these particles may be weakened, they may not pass through the body of the device, they will not fall into the sensitive element and will not be detected.

Doctor of Physical and Mathematical Sciences, Professor of MEPhI N.M. Gavrilov
the article was written for the company "Kvarta-Rad"

After the accident at the Fukushima nuclear power plant, another wave of panic radiophobia swept the world. On the Far East Iodine disappeared from the sale, and manufacturers and sellers of dosimeters not only sold out all the devices available in warehouses, but also collected pre-orders for six months or a year in advance. But is radiation really that bad? If you wince every time you hear that word, this article is for you.

What is radiation? This is the name of various types of ionizing radiation, that is, one that is capable of tearing off electrons from the atoms of a substance. The three main types of ionizing radiation are usually denoted by the Greek letters alpha, beta and gamma. Alpha radiation is a stream of helium-4 nuclei (virtually all helium from balloons was once alpha radiation), beta radiation is a stream of fast electrons (less often positrons), and gamma is a stream of high-energy photons. Another type of radiation is the neutron flux. Ionizing radiation (with the exception of X-rays) is the result of nuclear reactions, so neither mobile phones, nor microwave ovens are its sources.

Loaded weapon

Of all the arts, the most important for us, as you know, is cinema, and of the types of radiation - gamma radiation. It has a very high penetrating power, and theoretically no barrier can completely protect against it. We are constantly exposed to gamma radiation, it comes to us through the thickness of the atmosphere from outer space, breaks through the soil layer and the walls of houses. back side such permeability is a relatively weak destructive effect: out of a large number of photons, only a small part will transfer its energy to the body. Soft (low-energy) gamma radiation (and X-rays) mainly interacts with matter, knocking out electrons from it due to the photoelectric effect, hard radiation is scattered by electrons, while the photon is not absorbed and retains a significant part of its energy, so the probability of destruction of molecules in such process is much less.

Beta radiation is close to gamma radiation in its effect - it also knocks electrons out of atoms. But with external irradiation, it is completely absorbed by the skin and tissues closest to the skin, not reaching internal organs. However, this leads to the fact that the flow of fast electrons transfers significant energy to the irradiated tissues, which can lead to radiation burns or provoke, for example, cataracts.

Alpha radiation carries significant energy and high momentum, which allows it to knock electrons out of atoms and even the atoms themselves out of molecules. Therefore, the “destruction” caused by them is much greater - it is believed that, having transferred 1 J of energy to the body, alpha radiation will cause the same damage as 20 J in the case of gamma or beta radiation. Fortunately, the penetrating power of alpha particles is extremely small: they are absorbed by the topmost layer of the skin. But when ingested, alpha-active isotopes are extremely dangerous: remember the infamous tea with alpha-active polonium-210, which poisoned Alexander Litvinenko.

Neutral danger

But the first place in the danger rating is undoubtedly occupied by fast neutrons. The neutron has no electric charge and therefore interacts not with electrons, but with nuclei - only with a "direct hit". A stream of fast neutrons can pass through a layer of matter, on average, from 2 to 10 cm without interacting with it. Moreover, in the case of heavy elements, colliding with the nucleus, the neutron only deviates to the side, almost without losing energy. And when colliding with a hydrogen nucleus (proton), the neutron transfers about half of its energy to it, knocking the proton out of its place. It is this fast proton (or, to a lesser extent, the nucleus of another light element) that causes ionization in matter, acting like alpha radiation. As a result, neutron radiation, like gamma quanta, easily penetrates into the body, but is almost completely absorbed there, creating fast protons that cause great destruction. In addition, neutrons are the very radiation that causes induced radioactivity in irradiated substances, that is, it turns stable isotopes into radioactive ones. This is an extremely unpleasant effect: for example, after being in the focus of a radiation accident, alpha, beta, and gamma-active dust can be washed off vehicles, but it is impossible to get rid of neutron activation - the body itself radiates (by the way, it was based on this the damaging effect of a neutron bomb that activated the armor of tanks).

Dose and Power

When measuring and evaluating radiation, such an amount is used different concepts and units that it is not surprising for an ordinary person to get confused.
The exposure dose is proportional to the number of ions that gamma and x-ray radiation creates in a unit mass of air. It is usually measured in roentgens (R).
The absorbed dose shows the amount of radiation energy absorbed by a unit mass of a substance. Previously, it was measured in rads (rad), and now - in grays (Gy).
The equivalent dose additionally takes into account the difference in destructive power different types radiation. Previously, it was measured in "biological equivalents of the rad" - rems (rem), and now - in sieverts (Sv).
The effective dose also takes into account the different sensitivity of different organs to radiation: for example, irradiating the hand is much less dangerous than the back or chest. Previously measured in the same rem, now in sieverts.
The conversion of some units of measurement into others is not always correct, but on average it is generally accepted that an exposure dose of gamma radiation of 1 R will bring the same harm to the body as an equivalent dose of 1/114 Sv. Converting rad to grays and rems to sieverts is very simple: 1 Gy = 100 rad, 1 Sv = 100 rem. To convert the absorbed dose into an equivalent dose, the so-called. "radiation quality factor", equal to 1 for gamma and beta radiation, 20 for alpha radiation and 10 for fast neutrons. For example, 1 Gy of fast neutrons = 10 Sv = 1000 rem.
The natural equivalent dose rate (ERR) of external exposure is usually 0.06 - 0.10 µSv/h, but in some places it can be less than 0.02 µSv/h or more than 0.30 µSv/h. A level of more than 1.2 µSv/h in Russia is officially considered dangerous, although in the cabin of an aircraft during a flight the DER can exceed this value many times over. And the crew of the ISS is exposed to radiation with a power of approximately 40 μSv / h.

In nature, neutron radiation is very small. In fact, the risk of being exposed to it exists only in the event of a nuclear bombardment or a serious accident at a nuclear power plant with a meltdown and release into the environment of most of the reactor core (and even then only in the first seconds).

Gas discharge meters

Radiation can be detected and measured using a variety of sensors. The simplest of these are ionization chambers, proportional counters, and gas-discharge Geiger-Muller counters. They are a thin-walled metal tube with gas (or air), along the axis of which a wire is stretched - an electrode. A voltage is applied between the body and the wire and the current flowing is measured. The fundamental difference between the sensors is only in the magnitude of the applied voltage: at low voltages we have an ionization chamber, at high voltages - a gas-discharge counter, somewhere in the middle - a proportional counter.

The plutonium-238 sphere glows in the dark like a one-watt light bulb. Plutonium is toxic, radioactive and incredibly heavy: one kilogram of this substance fits in a cube with a side of 4 cm.

Ionization chambers and proportional counters make it possible to determine the energy that each particle has transferred to the gas. The Geiger-Muller counter only counts particles, but readings from it are very easy to receive and process: the power of each pulse is sufficient to directly output it to a small speaker! Important problem gas-discharge counters - the dependence of the counting rate on the radiation energy at the same level of radiation. To align it, special filters are used that absorb part of the soft gamma and all beta radiation. To measure the flux density of beta and alpha particles, such filters are made removable. In addition, to increase the sensitivity to beta and alpha radiation, "end counters" are used: this is a disk with a bottom as one electrode and a second spiral wire electrode. The cover of end counters is made of a very thin (10–20 µm) plate of mica, through which soft beta radiation and even alpha particles easily pass.

Semiconductors and scintillators

Instead of an ionization chamber, a semiconductor sensor can be used. The simplest example is an ordinary diode to which a blocking voltage is applied: when an ionizing particle enters a p-n junction, it creates additional charge carriers, which lead to the appearance of a current pulse. To increase the sensitivity, so-called pin diodes are used, where there is a relatively thick layer of undoped semiconductor between the layers of p- and n-semiconductors. Such sensors are compact and allow to measure particle energy with high accuracy. But the volume of the sensitive area is small, and therefore the sensitivity is limited. In addition, they are much more expensive than gas-discharge ones.

Another principle is counting and measuring the brightness of flashes that occur in certain substances when particles of ionizing radiation are absorbed. These flashes cannot be seen with the naked eye, but special highly sensitive devices - photomultiplier tubes - are capable of this. They even allow you to measure the change in brightness over time, which characterizes the energy loss of each individual particle. Sensors based on this principle are called scintillator sensors.

Radiation Shield

For protection against gamma radiation, heavy elements such as lead are most effective. The larger the number of the element in the periodic table, the stronger the photoelectric effect manifests itself in it. The degree of protection also depends on the energy of the radiation particles. Even lead attenuates radiation from caesium-137 (662 keV) by only a factor of two for every 5 mm of its thickness. In the case of cobalt-60 (1173 and 1333 keV), more than a centimeter of lead is required for a twofold attenuation. Only for soft gamma radiation, such as the radiation of cobalt-57 (122 keV), a sufficiently thin layer of lead will be a serious protection: 1 mm will attenuate it by a factor of ten. So anti-radiation suits from movies and computer games in reality, they only protect against soft gamma radiation.

Beta radiation is completely absorbed by the protection of a certain thickness. For example, the beta radiation of cesium-137 with a maximum energy of 514 keV (and an average of 174 keV) is completely absorbed by a layer of water 2 mm thick or only 0.6 mm of aluminum. But lead should not be used to protect against beta radiation: too rapid deceleration of beta electrons leads to the formation x-ray radiation. To completely absorb the radiation of strontium-90, you need less than 1.5 mm of lead, but it takes another centimeter to absorb the resulting X-ray radiation!

Folk remedies

There is a well-established myth about the "protective" effect of alcohol, but it has no basis in scientific justification. Even if red wine contains natural antioxidants that could theoretically act as radioprotectors, their theoretical benefit is outweighed by the practical harm of ethanol, which damages cells and is a neurotoxic poison.
The extremely tenacious popular recommendation to drink iodine so as not to “get infected with radiation” is justified only for a 30-kilometer zone around a freshly exploded nuclear power plant. In this case, potassium iodide is used to "keep out" radioactive iodine-131 into the thyroid gland (half-life - 8 days). The tactic of the lesser evil is used: let the thyroid gland be “clogged” with ordinary rather than radioactive iodine. And the prospect of getting a dysfunction of the thyroid gland pales before cancer or even death. But outside the zone of infection, swallowing pills, drinking an alcoholic solution of iodine or smearing it on the neck from the front does not make any sense - it has no preventive value, but you can easily earn iodine poisoning and turn yourself into a life-long patient of an endocrinologist.

It is easiest to protect yourself from external alpha radiation: a sheet of paper is enough for this. However, most alpha particles do not pass through the air even five centimeters, so protection may be required only in case of direct contact with a radioactive source. It is much more important to protect against the ingress of alpha-active isotopes into the body, for which a respirator mask is used, and ideally an airtight suit with an isolated breathing system.

Finally, hydrogen-rich substances are best protected from fast neutrons. For example, hydrocarbons, the best option is polyethylene. Experiencing collisions with hydrogen atoms, the neutron quickly loses energy, slows down and soon becomes unable to cause ionization. However, such neutrons can still activate, that is, transform into radioactive, many stable isotopes. Therefore, boron is often added to neutron shielding, which very strongly absorbs such slow (they are called thermal) neutrons. Alas, the thickness of polyethylene for reliable protection must be at least 10 cm. So it turns out to be slightly lighter than lead protection against gamma radiation.

radiation pills

Human body more than three-quarters consists of water, so the main action of ionizing radiation is radiolysis (decomposition of water). The resulting free radicals cause an avalanche cascade of pathological reactions with the appearance of secondary "fragments". In addition, radiation damages chemical bonds in nucleic acid molecules, causing disintegration and depolymerization of DNA and RNA. The most important enzymes containing a sulfhydryl group - SH (adenosine triphosphatase, succinoxidase, hexokinase, carboxylase, cholinesterase) are inactivated. At the same time, the processes of biosynthesis and energy metabolism are disrupted, proteolytic enzymes are released from the destroyed organelles into the cytoplasm, and self-digestion begins. In the risk group, first of all, there are germ cells, precursors shaped elements blood, cells of the gastrointestinal tract and lymphocytes, but neurons and muscle cells are quite resistant to ionizing radiation.

Preparations capable of protecting against the effects of radiation began to be actively developed in the middle of the 20th century. Only some aminothiols, such as cystamine, cysteamine, aminoethylisothiuronium, turned out to be more or less effective and suitable for mass use. In fact, they are donors - SH groups, exposing them to attack instead of "relatives".

Radiation around us

To face radiation "face to face", accidents are not necessary at all. radioactive substances widely used in everyday life. Potassium is naturally radioactive and is a very important element for all living things. Due to the small admixture of the K-40 isotope in natural potassium, dietary salt and potash fertilizers “phonite”. Some older lenses used thorium oxide glass. The same element is added to some modern electrodes for argon welding. Until the middle of the 20th century, devices with illumination based on radium were actively used (in our time, radium was replaced by a less dangerous tritium). Some smoke detectors use an alpha emitter based on americium-241 or highly enriched plutonium-239 (yes, the same one from which nuclear bombs are made). But do not worry - the harm to health from all these sources is much less than the harm from worrying about this.