The impact of ionizing rays on humans. Ionizing radiation, health effects and protective measures

Man is exposed to ionizing radiation everywhere. To do this, it is not necessary to fall into the epicenter of a nuclear explosion, it is enough to be under the scorching sun or to conduct an x-ray examination of the lungs.

Ionizing radiation is a stream of radiation energy generated during the reactions of the decay of radioactive substances. Isotopes that can increase the radiation fund are found in the earth's crust, in the air; radionuclides can enter the human body through the gastrointestinal tract, respiratory system and skin.

The minimum indicators of the radiation background do not pose a threat to humans. The situation is different if the ionizing radiation exceeds the permissible limits. The body will not instantly respond to harmful rays, but years later pathological changes will appear that can lead to disastrous consequences, even death.

What is ionizing radiation?

The release of harmful radiation is obtained after the chemical decay of radioactive elements. The most common are gamma, beta and alpha rays. Getting into the body, radiation has a destructive effect on a person. All biochemical processes are disturbed under the influence of ionization.

Types of radiation:

Alpha-type rays have increased ionization, but meager penetrating power. Alpha radiation hits the human skin, penetrating a distance of less than one millimeter. It is a beam of released helium nuclei.
Electrons or positrons move in beta rays, in an air stream they are able to overcome distances of up to several meters. If a person appears near the source, beta radiation will penetrate deeper than alpha radiation, but this species has much less ionizing abilities.
One of the highest frequency electromagnetic radiations is the gamma variety, which has a high penetrating power but very little ionizing effect.
characterized by short electromagnetic waves that occur when beta rays come into contact with matter.
Neutron - highly penetrating beams of rays, consisting of uncharged particles.

Where does radiation come from?

Sources of ionizing radiation can be air, water and food. Harmful rays occur naturally or are artificially created for medical or industrial purposes. Radiation is always present in the environment:

comes from space and makes up a large part of the total percentage of radiation;
radiation isotopes are freely found in familiar natural conditions, contained in rocks;
radionuclides enter the body with food or through the air.

Artificial radiation was created in the conditions of developing science, scientists were able to discover the uniqueness of X-rays, with the help of which it is possible to accurately diagnose many dangerous pathologies, including infectious diseases.

On an industrial scale, ionizing radiation is used for diagnostic purposes. People working at such enterprises, despite all the safety measures applied in accordance with sanitary requirements, are in harmful and dangerous working conditions that adversely affect their health.

What happens to a person with ionizing radiation?

The destructive effect of ionizing radiation on the human body is explained by the ability of radioactive ions to react with the constituents of cells. It is well known that eighty percent of a person consists of water. When irradiated, water decomposes, and as a result of chemical reactions, hydrogen peroxide and hydrated oxide are formed in cells.

Subsequently, oxidation occurs in the organic compounds of the body, as a result of which the cells begin to collapse. After a pathological interaction, a person's metabolism is disrupted at the cellular level. The effects may be reversible when exposure to radiation has been minor, and irreversible with prolonged exposure.

The effect on the body can manifest itself in the form of radiation sickness, when all organs are affected, radioactive rays can cause gene mutations that are inherited in the form of deformities or serious illnesses. There are frequent cases of degeneration of healthy cells into cancer cells, followed by the growth of malignant tumors.

The consequences may appear not immediately after interaction with ionizing radiation, but after decades. The duration of the asymptomatic course directly depends on the degree and time during which the person received radioactive exposure.

Biological changes under the action of rays

Exposure to ionizing radiation entails significant changes in the body, depending on the extent of the area of the skin exposed to the introduction of radiation energy, the time during which the radiation remains active, as well as the state of organs and systems.

To denote the strength of radiation over a certain period of time, the unit of measurement is considered to be Rad. Depending on the size of the transmitted rays, a person may develop the following conditions:

up to 25 rad - general well-being does not change, the person feels good;
26 - 49 rad - the condition is generally satisfactory, with this dosage, the blood begins to change its composition;
50 - 99 rad - the victim begins to feel general malaise, fatigue, bad mood, pathological changes appear in the blood;
100 - 199 rad - the irradiated person is in poor condition, most often a person cannot work due to deteriorating health;
200 - 399 rad - a large dose of radiation, which develops multiple complications, and sometimes leads to death;
400 - 499 rad - half of the people who fall into the zone with such radiation values \u200b\u200bare dying from frolicking pathologies;
exposure to more than 600 rad does not give a chance for a successful outcome, a fatal disease takes the lives of all victims;
a one-time receipt of a radiation dose that is thousands of times greater than the allowable figures - everyone perishes directly during the disaster.

The age of a person plays a big role: the most susceptible to the negative influence of ionizing energy are children and young people who have not reached the age of twenty-five. Receiving large doses of radiation during pregnancy can be compared with exposure in early childhood.

Brain pathologies occur only from the middle of the first trimester, from the eighth week to the twenty-sixth inclusive. The risk of cancer in the fetus increases significantly with an unfavorable radiation background.

What threatens to get under the influence of ionizing rays?

A one-time or regular exposure to radiation in the body has the property of accumulation and subsequent reactions after a certain period of time from several months to decades:

the inability to conceive a child, this complication develops both in women and in the male half, making them sterile;
the development of autoimmune diseases of unknown etiology, in particular multiple sclerosis;
radiation cataract leading to loss of vision;
the appearance of a cancerous tumor is one of the most common pathologies with tissue modification;
diseases of an immune nature that disrupt the usual work of all organs and systems;
a person exposed to radiation lives much less;
the development of mutating genes that will cause serious malformations, as well as the appearance of abnormal deformities during the development of the fetus.

Remote manifestations may develop directly in the exposed individual or be inherited and occur in subsequent generations. Directly at the diseased place through which the rays passed, changes occur in which the tissues atrophy and thicken with the appearance of multiple nodules.

This symptom can affect the skin, lungs, blood vessels, kidneys, liver cells, cartilage and connective tissues. Groups of cells become inelastic, coarsen and lose the ability to fulfill their purpose in the human body with radiation sickness.

Radiation sickness

One of the most formidable complications, different stages of development of which can lead to the death of the victim. The disease can have an acute course with a single exposure or a chronic process with a constant stay in the radiation zone. Pathology is characterized by a persistent change in all organs and cells and the accumulation of pathological energy in the patient's body.

The disease manifests itself with the following symptoms:

general intoxication of the body with vomiting, diarrhea and fever;
on the part of the cardiovascular system, the development of hypotension is noted;
a person gets tired quickly, collapses may occur;
at high doses of exposure, the skin turns red and becomes covered with blue spots in areas that lack oxygen supply, muscle tone decreases;
the second wave of symptoms is total hair loss, deterioration of health, consciousness remains slow, there is general nervousness, atony of muscle tissue, disorders in the brain that can cause clouding of consciousness and cerebral edema.

How to protect yourself from radiation?

Determination of effective protection against harmful rays underlies the prevention of human injury in order to avoid the appearance of negative consequences. To save yourself from radiation, you must:

Reduce the time of exposure to isotope decay elements: a person should not be in the danger zone for a long period. For example, if a person works in hazardous production, the worker's stay in the place of energy flow should be reduced to a minimum.
To increase the distance from the source, it is possible to do this using multiple tools and automation tools that allow you to work at a considerable distance from external sources with ionizing energy.
It is necessary to reduce the area on which the rays fall with the help of protective equipment: suits, respirators.

Passing through matter, all types of ionizing radiation cause ionization, excitation and decay of molecules. A similar effect is observed during irradiation of the human body. Since the bulk (70%) of the body is water, its damage during irradiation is carried out through the so-called indirect impact: first, the radiation is absorbed by water molecules, and then ions, excited molecules and fragments of decayed molecules enter into chemical reactions with biological substances that make up the human body, causing their damage. In the case of irradiation with neutrons, radionuclides can be additionally formed in the body due to the absorption of neutrons by the nuclei of the elements contained in the body.

Penetrating into the human body, ionizing radiation can cause serious illness. The physical, chemical and biological transformations of a substance during the interaction of ionizing radiation with it are called radiation effect, which can lead to such serious diseases as radiation sickness, leukemia (leukemia), malignant tumors, skin diseases. There may also be genetic consequences leading to hereditary diseases.

Ionization of living tissue leads to the breaking of molecular bonds and changes in the chemical structure of compounds. Changes in the chemical composition of molecules lead to cell death. In living tissue, water is split into atomic hydrogen and a hydroxyl group, which form new chemical compounds that are not characteristic of healthy tissue. As a result of the changes that have taken place, the normal course of biochemical processes and metabolism are disturbed.

Irradiation of the human body can be external and internal. At external exposure, which is created by sealed sources, dangerous radiation with high penetrating power. Internal exposure occurs when radioactive substances enter the body by inhalation of air contaminated with radioactive elements, through the digestive tract (through eating, contaminated water and smoking) and in rare cases through the skin. The body is exposed to internal radiation until the radioactive substance decays or is excreted as a result of physiological metabolism, therefore, radioactive isotopes with a long half-life and intense radiation pose the greatest danger. The nature of the injuries and their severity are determined by the absorbed radiation energy, which primarily depends on the absorbed dose rate, as well as on the type of radiation, the duration of exposure, the biological characteristics and size of the irradiated part of the body, and the individual sensitivity of the organism.

Under the influence of various types of radioactive radiation on living tissues, the penetrating and ionizing abilities of the radiation are decisive. Penetrating power of radiation characterized run length 1– the thickness of the material required to absorb the flow. For example, the path length of alpha particles in living tissue is several tens of micrometers, and in air it is 8–9 cm. Therefore, during external irradiation, the skin protects the body from the effects of alpha and soft beta radiation, the penetrating power of which is low.

Different types of radiation at the same values of the absorbed dose cause different biological damage.

Illnesses caused by radiation can be acute or chronic. Acute lesions occur when irradiated with large doses in a short time. Very often, after recovery, early aging sets in, and previous diseases become aggravated. Chronic lesions ionizing radiation are both general and local. They always develop in a latent form as a result of systematic irradiation with doses exceeding the maximum allowable, obtained both during external exposure and when radioactive substances enter the body.

The danger of radiation injury largely depends on which organ has been exposed to radiation. According to the selective ability to accumulate in individual critical organs (with internal exposure), radioactive substances can be divided into three groups:

- tin, antimony, tellurium, niobium, polonium, etc. are evenly distributed in the body;
- lanthanum, cerium, actinium, thorium, etc. accumulate mainly in the liver;
- uranium, radium, zirconium, plutonium, strontium, etc. accumulate in the skeleton.

The individual sensitivity of the body affects at low doses of radiation (less than 50 mSv/year), with increasing doses it manifests itself to a lesser extent. The body is most resistant to radiation at the age of 25–30 years. Disease of the nervous system and internal organs reduces the body's resistance to radiation.

When determining radiation doses, the main data are data on the quantitative content of radioactive substances in the human body, and not data on their concentration in the environment.

Radioactive substances (RS) can enter the body in three ways: with inhaled air, through the gastrointestinal tract (with food and water), through the skin. A person receives radiation not only from the outside, but also through the internal organs. RV penetrate the molecules of internal organs, especially bone tissue and muscles. Concentrating in them, RVs continue to irradiate and damage the body from the inside.

Radiation risk is the probability that a person or his offspring will experience any harmful effect as a result of exposure to radiation.

Ionizing radiation, when exposed to the human body, can cause adverse effects of two types:

Deterministic (radiation sickness, radiation dermatitis, radiation cataract, radiation infertility, abnormalities in the development of the fetus, etc.). It is assumed that there is a dose threshold, below which there is no effect, and above which the severity of the effect depends on the dose;

Stochastic probabilistic non-threshold harmful biological effects (malignant tumors, leukemia, hereditary diseases) that do not have a dose threshold of occurrence. The severity of their manifestation does not depend on the dose. The period of occurrence of these effects in an irradiated person ranges from 2 to 50 years or more.

The biological effect of ionizing radiation is associated with the formation of new compounds that are not characteristic of the body, disrupting the activity of both individual functions and entire body systems. Partially, there are processes of restoring the structures of the body. The overall result of recovery depends on the intensity of these processes. With an increase in the radiation power, the significance of the recovery processes decreases.

There are genetic (hereditary) and somatic (bodily) harmful effects.

Genetic effects are associated with changes in the gene apparatus under the influence of ionizing radiation. The consequences of this are mutations (the appearance of offspring in irradiated people with other characteristics, often with congenital deformities).

Genetic effects have a long latent period (tens of years after exposure). Such a danger exists even with very weak radiation, which, although it does not destroy cells, can change hereditary properties.

Somatic effects always begin at a certain threshold dose. At doses less than the threshold, damage to the body does not occur. Somatic effects include local damage to the skin (radiation burn), eye cataracts (clouding of the lens), damage to the genital organs (short-term or permanent sterilization). The body is able to overcome many of the somatic effects of radiation exposure.

The degree of radiation damage depends to a large extent on the size of the irradiated surface, on whether the whole body or only part of it was exposed to radiation. With its reduction, the biological effect also decreases.

Long-term exposure to low doses (chronic) in the working environment can lead to the development of chronic radiation sickness. The most characteristic signs of chronic radiation sickness are changes in the blood count, local skin lesions, lesions of the lens, pneumosclerosis, and decreased immunity. The ability to cause long-term effects is one of the insidious properties of ionizing radiation.

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Introduction

Natural ionizing radiation is present everywhere. It comes from space in the form of cosmic rays. It is in the air in the form of radiation of radioactive radon and its secondary particles. Radioactive isotopes of natural origin penetrate with food and water into all living organisms and remain in them. Ionizing radiation cannot be avoided. The natural radioactive background has always existed on Earth, and life originated in the field of its radiation, and then - much, much later - man appeared. This natural (natural) radiation accompanies us throughout our lives.

The physical phenomenon of radioactivity was discovered in 1896, and today it is widely used in many fields. Despite radiophobia, nuclear power plants play an important role in the energy sector in many countries. X-rays are used in medicine to diagnose internal injuries and diseases. A number of radioactive substances are used in the form of labeled atoms to study the functioning of internal organs and study metabolic processes. Radiation therapy uses gamma radiation and other types of ionizing radiation to treat cancer. Radioactive substances are widely used in various control devices, and ionizing radiation (primarily X-ray) is used for the purposes of industrial flaw detection. Exit signs on buildings and planes, thanks to the content of radioactive tritium, glow in the dark in the event of a sudden power outage. Many fire alarms in homes and public buildings contain radioactive americium.

Radioactive radiation of different types with different energy spectrum are characterized by different penetrating and ionizing ability. These properties determine the nature of their impact on the living matter of biological objects.

It is believed that some of the hereditary changes and mutations in animals and plants are associated with background radiation.

In the event of a nuclear explosion, a nuclear lesion center occurs on the ground - a territory where the factors of mass destruction of people are light radiation, penetrating radiation and radioactive contamination of the area.

As a result of the damaging effect of light radiation, massive burns and eye damage can occur. Various kinds of shelters are suitable for protection, and in open areas - special clothing and goggles.

Penetrating radiation is gamma rays and a stream of neutrons emanating from the zone of a nuclear explosion. They can spread over thousands of meters, penetrate various media, causing ionization of atoms and molecules. Penetrating into the tissues of the body, gamma rays and neutrons disrupt the biological processes and functions of organs and tissues, resulting in the development of radiation sickness. Radioactive contamination of the area is created due to the adsorption of radioactive atoms by soil particles (the so-called radioactive cloud, which moves in the direction of air movement). The main danger for people in contaminated areas is external beta-gamma radiation and the ingress of nuclear explosion products into the body and onto the skin.

Nuclear explosions, releases of radionuclides from nuclear power plants and the widespread use of ionizing radiation sources in various industries, agriculture, medicine and scientific research have led to a global increase in the exposure of the Earth's population. Anthropogenic sources of external and internal exposure were added to natural exposure.

During nuclear explosions, fission radionuclides, induced activity and the undivided part of the charge (uranium, plutonium) enter the environment. Induced activity occurs when neutrons are captured by the nuclei of atoms of elements located in the structure of the product, air, soil and water. According to the nature of the radiation, all radionuclides of fission and induced activity are classified as - or, - emitters.

Fallouts are divided into local and global (tropospheric and stratospheric). Local fallout, which may include over 50% of the radioactive material generated from ground explosions, is large aerosol particles that fall out at a distance of about 100 km from the explosion site. Global fallout is due to fine aerosol particles.

Radionuclides deposited on the earth's surface become a source of long-term exposure.

The impact of radioactive fallout on humans includes external -, - exposure due to radionuclides present in the surface air and deposited on the surface of the earth, contact exposure as a result of contamination of skin and clothing, and internal exposure from radionuclides that enter the body with inhaled air and contaminated food and water. The critical radionuclide in the initial period is radioactive iodine, and subsequently 137Cs and 90Sr.

1. History of the discovery of radioactive radiation

Radioactivity was discovered in 1896 by the French physicist A. Becquerel. He was engaged in the study of the connection between luminescence and the recently discovered x-rays.

Becquerel came up with the idea: is not any luminescence accompanied by x-rays? To test his guess, he took several compounds, including one of the uranium salts, which phosphorescent yellow-green light. After illuminating it with sunlight, he wrapped the salt in black paper and placed it in a dark closet on a photographic plate, also wrapped in black paper. Some time later, having shown the plate, Becquerel really saw the image of a piece of salt. But luminescent radiation could not pass through the black paper, and only X-rays could illuminate the plate under these conditions. Becquerel repeated the experiment several times with equal success. At the end of February 1896, at a meeting of the French Academy of Sciences, he made a report on the X-ray emission of phosphorescent substances.

After some time, a plate was accidentally developed in Becquerel's laboratory, on which lay uranium salt, not irradiated by sunlight. She, of course, did not phosphoresce, but the imprint on the plate turned out. Then Becquerel began to test various compounds and minerals of uranium (including those that do not show phosphorescence), as well as metallic uranium. The plate was constantly lit up. By placing a metal cross between the salt and the plate, Becquerel obtained the weak contours of the cross on the plate. Then it became clear that new rays were discovered that pass through opaque objects, but are not X-rays.

Becquerel established that the intensity of radiation is determined only by the amount of uranium in the preparation and does not depend at all on what compounds it is included in. Thus, this property was inherent not in compounds, but in the chemical element - uranium.

Becquerel shares his discovery with the scientists with whom he collaborated. In 1898, Marie Curie and Pierre Curie discovered the radioactivity of thorium, and later they discovered the radioactive elements polonium and radium.

They found that all uranium compounds and, to the greatest extent, uranium itself have the property of natural radioactivity. Becquerel returned to the luminophores that interested him. True, he made another major discovery related to radioactivity. Once, for a public lecture, Becquerel needed a radioactive substance, he took it from the Curies and put the test tube in his vest pocket. After giving a lecture, he returned the radioactive preparation to the owners, and the next day he found redness of the skin in the form of a test tube on the body under the vest pocket. Becquerel told Pierre Curie about this, and he set up an experiment: for ten hours he wore a test tube with radium tied to his forearm. A few days later he also developed redness, which then turned into a severe ulcer, from which he suffered for two months. Thus, the biological effect of radioactivity was discovered for the first time.

But even after that, the Curies courageously did their job. Suffice it to say that Marie Curie died of radiation sickness (nevertheless, she lived to be 66 years old).

In 1955 Marie Curie's notebooks were examined. They still radiate, thanks to the radioactive contamination introduced when they were filled. On one of the sheets, a radioactive fingerprint of Pierre Curie was preserved.

The concept of radioactivity and types of radiation.

Radioactivity - the ability of some atomic nuclei to spontaneously (spontaneously) transform into other nuclei with the emission of various types of radioactive radiation and elementary particles. Radioactivity is divided into natural (observed in unstable isotopes that exist in nature) and artificial (observed in isotopes obtained through nuclear reactions).

Radioactive radiation is divided into three types:

Radiation - is deflected by electric and magnetic fields, has a high ionizing ability and low penetrating power; is a stream of helium nuclei; the charge of the -particle is +2e, and the mass coincides with the mass of the nucleus of the helium isotope 42He.

Radiation - deflected by electric and magnetic fields; its ionizing power is much less (by about two orders of magnitude), and its penetrating power is much greater than that of -particles; is a stream of fast electrons.

Radiation - is not deflected by electric and magnetic fields, has a relatively weak ionizing ability and a very high penetrating power; is short-wave electromagnetic radiation with an extremely short wavelength< 10-10 м и вследствие этого - ярко выраженными корпускулярными свойствами, то есть является поток частиц - -квантов (фотонов).

The half-life T1 / 2 is the time during which the initial number of radioactive nuclei is on average halved.

Alpha radiation is a stream of positively charged particles formed by 2 protons and 2 neutrons. The particle is identical to the nucleus of the helium-4 atom (4He2+). It is formed during the alpha decay of nuclei. For the first time, alpha radiation was discovered by E. Rutherford. Studying radioactive elements, in particular, studying such radioactive elements as uranium, radium and actinium, E. Rutherford came to the conclusion that all radioactive elements emit alpha and beta rays. And, more importantly, the radioactivity of any radioactive element decreases after a certain specific period of time. The source of alpha radiation is radioactive elements. Unlike other types of ionizing radiation, alpha radiation is the most harmless. It is dangerous only when such a substance enters the body (inhalation, eating, drinking, rubbing, etc.), since the range of an alpha particle, for example, with an energy of 5 MeV, in air is 3.7 cm, and in biological tissue 0, 05 mm. The alpha radiation of a radionuclide that has entered the body causes truly nightmarish destruction, tk. the quality factor of alpha radiation with energy less than 10 MeV is 20mm. and energy losses occur in a very thin layer of biological tissue. It practically burns him. When alpha particles are absorbed by living organisms, mutagenic (factors that cause mutation), carcinogenic (substances or a physical agent (radiation) that can cause the development of malignant neoplasms) and other negative effects can occur. Penetrating ability A. - and. small because held back by a piece of paper.

Beta particle (beta particle), a charged particle emitted as a result of beta decay. The stream of beta particles is called beta rays or beta radiation.

Negatively charged beta particles are electrons (in--), positively charged are positrons (in +).

The energies of beta particles are distributed continuously from zero to some maximum energy, depending on the decaying isotope; this maximum energy ranges from 2.5 keV (for rhenium-187) to tens of MeV (for short-lived nuclei far from the beta stability line).

Beta rays under the action of electric and magnetic fields deviate from a rectilinear direction. The speed of particles in beta rays is close to the speed of light. Beta rays are able to ionize gases, cause chemical reactions, luminescence, act on photographic plates.

Significant doses of external beta radiation can cause radiation burns to the skin and lead to radiation sickness. Even more dangerous is internal exposure from beta-active radionuclides that have entered the body. Beta radiation has a significantly lower penetrating power than gamma radiation (however, an order of magnitude greater than alpha radiation). A layer of any substance with a surface density of the order of 1 g/cm2.

For example, a few millimeters of aluminum or a few meters of air almost completely absorb beta particles with an energy of about 1 MeV.

Gamma radiation is a type of electromagnetic radiation with an extremely short wavelength --< 5Ч10-3 нм и вследствие этого ярко выраженными корпускулярными и слабо выраженными волновыми свойствами. Гамма-квантами являются фотоны высокой энергии. Обычно считается, что энергии квантов гамма-излучения превышают 105 эВ, хотя резкая граница между гамма- и рентгеновским излучением не определена. На шкале электромагнитных волн гамма-излучение граничит с рентгеновским излучением, занимая диапазон более высоких частот и энергий. В области 1-100 кэВ гамма-излучение и рентгеновское излучение различаются только по источнику: если квант излучается в ядерном переходе, то его принято относить к гамма-излучению, если при взаимодействиях электронов или при переходах в атомной электронной оболочке -- то к рентгеновскому излучению. Очевидно, физически кванты электромагнитного излучения с одинаковой энергией не отличаются, поэтому такое разделение условно.

Gamma radiation is emitted during transitions between excited states of atomic nuclei (the energies of such gamma rays range from ~1 keV to tens of MeV). During nuclear reactions (for example, during the annihilation of an electron and a positron, the decay of a neutral pion, etc.), as well as during the deflection of energetic charged particles in magnetic and electric fields.

Gamma rays, unlike b-rays and b-rays, are not deflected by electric and magnetic fields and are characterized by greater penetrating power at equal energies and other conditions being equal. Gamma rays cause the ionization of the atoms of matter. The main processes that occur during the passage of gamma radiation through matter:

Photoelectric effect (gamma quantum is absorbed by the electron of the atomic shell, transferring all the energy to it and ionizing the atom).

Compton scattering (gamma-quantum is scattered by an electron, transferring to it part of its energy).

The birth of electron-positron pairs (in the field of the nucleus, a gamma quantum with an energy of at least 2mec2=1.022 MeV turns into an electron and a positron).

Photonuclear processes (at energies above several tens of MeV, a gamma quantum is able to knock out nucleons from the nucleus).

Gamma rays, like any other photons, can be polarized.

Irradiation with gamma rays, depending on the dose and duration, can cause chronic and acute radiation sickness. Stochastic effects of radiation include various types of cancer. At the same time, gamma radiation inhibits the growth of cancerous and other rapidly dividing cells. Gamma radiation is a mutagenic and teratogenic factor.

A layer of matter can serve as protection against gamma radiation. The effectiveness of protection (that is, the probability of absorption of a gamma-quantum when passing through it) increases with an increase in the thickness of the layer, the density of the substance and the content of heavy nuclei (lead, tungsten, depleted uranium, etc.) in it.

The unit for measuring radioactivity is the becquerel (Bq, Bq). One becquerel is equal to one disintegration per second. The content of activity in a substance is often estimated per unit weight of the substance (Bq/kg) or its volume (Bq/l, Bq/m3). An off-system unit is often used - the curie (Ci, Ci). One curie corresponds to the number of disintegrations per second in 1 gram of radium. 1 Ki \u003d 3.7.1010 Bq.

The ratios between units of measurement are shown in the table below.

The well-known non-systemic unit roentgen (P, R) is used to determine the exposure dose. One X-ray corresponds to the dose of X-ray or gamma radiation, at which 2.109 pairs of ions are formed in 1 cm3 of air. 1 Р = 2, 58.10-4 C/kg.

To evaluate the effect of radiation on a substance, the absorbed dose is measured, which is defined as the absorbed energy per unit mass. The unit of absorbed dose is called the rad. One rad is equal to 100 erg/g. In the SI system, another unit is used - gray (Gy, Gy). 1 Gy \u003d 100 rad \u003d 1 J / kg.

The biological effect of different types of radiation is not the same. This is due to differences in their penetrating ability and the nature of energy transfer to organs and tissues of a living organism. Therefore, to assess the biological consequences, the biological equivalent of an x-ray, rem, is used. The dose in rems is equivalent to the dose in rads multiplied by the radiation quality factor. For x-rays, beta and gamma rays, the quality factor is considered to be equal to one, that is, rem corresponds to a rad. For alpha particles, the quality factor is 20 (meaning that alpha particles cause 20 times more damage to living tissue than the same absorbed dose of beta or gamma rays). For neutrons, the coefficient ranges from 5 to 20, depending on the energy. In the SI system for equivalent dose, a special unit called sievert (Sv, Sv) was introduced. 1 Sv = 100 rem. The equivalent dose in Sieverts corresponds to the absorbed dose in Gy multiplied by the quality factor.

2. The impact of radiation on the human body

There are two types of effect of exposure to ionizing radiation on the body: somatic and genetic. With a somatic effect, the consequences are manifested directly in the irradiated person, with a genetic effect, in his offspring. Somatic effects may be early or delayed. Early ones occur in the period from several minutes to 30-60 days after irradiation. These include redness and peeling of the skin, clouding of the lens of the eye, damage to the hematopoietic system, radiation sickness, death. Long-term somatic effects appear several months or years after irradiation in the form of persistent skin changes, malignant neoplasms, decreased immunity, and reduced life expectancy.

When studying the effect of radiation on the body, the following features were revealed:

ü High efficiency of absorbed energy, even small amounts of it can cause profound biological changes in the body.

b The presence of a latent (incubation) period for the manifestation of the action of ionizing radiation.

b Effects from low doses may be cumulative or cumulative.

b Genetic effect - effect on offspring.

Various organs of a living organism have their own sensitivity to radiation.

Not every organism (human) as a whole reacts equally to radiation.

Irradiation depends on the frequency of exposure. With the same dose of radiation, the harmful effects will be the less, the more fractionally it is received in time.

Ionizing radiation can affect the body with both external (especially X-ray and gamma radiation) and internal (especially alpha particles) radiation. Internal exposure occurs when sources of ionizing radiation enter the body through the lungs, skin and digestive organs. Internal irradiation is more dangerous than external, since sources of ionizing radiation that have got inside expose unprotected internal organs to continuous irradiation.

Under the action of ionizing radiation, water, which is an integral part of the human body, is split and ions with different charges are formed. The resulting free radicals and oxidizing agents interact with the molecules of the organic matter of the tissue, oxidizing and destroying it. Metabolism is disturbed. There are changes in the composition of the blood - the level of erythrocytes, leukocytes, platelets and neutrophils decreases. Damage to the hematopoietic organs destroys the human immune system and leads to infectious complications.

Local lesions are characterized by radiation burns of the skin and mucous membranes. With severe burns, edema, blisters are formed, tissue death (necrosis) is possible.

Lethally absorbed and maximum allowable doses of radiation.

Lethal absorbed doses for individual parts of the body are as follows:

b head - 20 Gy;

b lower abdomen - 50 Gy;

b chest -100 Gy;

e limbs - 200 Gr.

When exposed to doses 100-1000 times the lethal dose, a person can die during exposure ("death under the beam").

Depending on the type of ionizing radiation, there may be different protection measures: reducing the exposure time, increasing the distance to sources of ionizing radiation, fencing sources of ionizing radiation, sealing sources of ionizing radiation, equipment and arrangement of protective equipment, organization of dosimetric control, hygiene and sanitation measures.

A - personnel, i.e. persons permanently or temporarily working with sources of ionizing radiation;

B - a limited part of the population, i.e. persons who are not directly involved in work with sources of ionizing radiation, but due to the conditions of residence or placement of workplaces, may be exposed to ionizing radiation;

B is the entire population.

The maximum allowable dose is the highest value of the individual equivalent dose per year, which, with uniform exposure for 50 years, will not cause adverse changes in the health of personnel detected by modern methods.

Tab. 2. Maximum allowable radiation doses

Natural sources give a total annual dose of approximately 200 mrem (space - up to 30 mrem, soil - up to 38 mrem, radioactive elements in human tissues - up to 37 mrem, radon gas - up to 80 mrem and other sources).

Artificial sources add an annual equivalent dose of approximately 150-200 mrem (medical devices and research - 100-150 mrem, TV viewing - 1-3 mrem, coal-fired thermal power plant - up to 6 mrem, consequences of nuclear weapons tests - up to 3 mrem and others sources).

The World Health Organization (WHO) defines the maximum allowable (safe) equivalent radiation dose for a planet inhabitant as 35 rem, subject to its uniform accumulation over 70 years of life.

Tab. 3. Biological disorders in a single (up to 4 days) irradiation of the entire human body

Radiation dose, (Gy)	The degree of radiation sickness	The beginning of the manifestation of the primary reaction	The nature of the primary reaction	Consequences of irradiation
Up to 0.250 - 1.0	There are no visible violations. There may be changes in the blood. Changes in the blood, impaired ability to work
		After 2-3 hours	Mild nausea with vomiting. Passes on the day of irradiation	Typically 100% recovery even with no treatment

3. Protection against ionizing radiation

Anti-radiation protection of the population includes: notification of radiation danger, the use of collective and individual protective equipment, compliance with the behavior of the population in the territory contaminated with radioactive substances. Protection of food and water from radioactive contamination, use of medical personal protective equipment, determination of levels of contamination of the territory, dosimetric control of public exposure and examination of contamination of food and water with radioactive substances.

According to the Civil Defense warning signals "Radiation Hazard", the population should take refuge in protective structures. As is known, they significantly (several times) weaken the effect of penetrating radiation.

Due to the danger of getting radiation damage, it is impossible to start providing first aid to the population in the presence of high levels of radiation in the area. Under these conditions, it is of great importance to provide self- and mutual assistance to the affected population, strict observance of the rules of conduct in the contaminated territory.

On the territory contaminated with radioactive substances, you can not eat, drink water from contaminated water sources, lie down on the ground. The procedure for cooking and feeding the population is determined by the Civil Defense authorities, taking into account the levels of radioactive contamination of the area.

Gas masks and respirators (for miners) can be used to protect against air contaminated with radioactive particles. There are also general protection methods such as:

l increasing the distance between the operator and the source;

ь reduction of the duration of work in the radiation field;

l shielding of the radiation source;

l remote control;

l use of manipulators and robots;

l full automation of the technological process;

ь use of personal protective equipment and warning with a radiation hazard sign;

ü constant monitoring of the level of radiation and radiation doses to personnel.

The personal protective equipment includes an anti-radiation suit with the inclusion of lead. The best absorber of gamma rays is lead. Slow neutrons are well absorbed by boron and cadmium. Fast neutrons are pre-moderated with graphite.

The Scandinavian company Handy-fashions.com is developing protection against radiation from mobile phones, for example, it introduced a vest, cap and scarf designed to protect against the harmful study of mobile phones. For their production, a special anti-radiation fabric is used. Only the pocket on the vest is made of ordinary fabric for stable signal reception. The cost of a complete protective kit is from $300.

Protection against internal exposure consists in eliminating direct contact of workers with radioactive particles and preventing them from entering the air of the working area.

It is necessary to be guided by radiation safety standards, which list the categories of exposed persons, dose limits and protection measures, and sanitary rules that regulate the location of premises and installations, the place of work, the procedure for obtaining, recording and storing radiation sources, requirements for ventilation, dust and gas cleaning, and neutralization radioactive waste, etc.

Also, to protect the premises with personnel, the Penza State Academy of Architecture and Civil Engineering is developing to create a "high-density mastic for protection against radiation." The composition of the mastics includes: binder - resorcinol-formaldehyde resin FR-12, hardener - paraformaldehyde and filler - high-density material.

Protection against alpha, beta, gamma rays.

The basic principles of radiation safety are not to exceed the established basic dose limit, to exclude any unreasonable exposure and to reduce the radiation dose to the lowest possible level. In order to implement these principles in practice, radiation doses received by personnel when working with sources of ionizing radiation are necessarily controlled, work is carried out in specially equipped rooms, protection is used by distance and time, and various means of collective and individual protection are used.

To determine the individual exposure doses of personnel, it is necessary to systematically carry out radiation (dosimetric) monitoring, the volume of which depends on the nature of work with radioactive substances. Each operator who has contact with sources of ionizing radiation is given an individual dosimeter1 to control the received dose of gamma radiation. In rooms where work with radioactive substances is carried out, it is necessary to provide general control over the intensity of various types of radiation. These rooms must be isolated from other rooms, equipped with a supply and exhaust ventilation system with an air exchange rate of at least five. The painting of the walls, ceiling and doors in these rooms, as well as the arrangement of the floor, are carried out in such a way as to exclude the accumulation of radioactive dust and avoid the absorption of radioactive aerosols. Vapors and liquids with finishing materials (painting of walls, doors and, in some cases, ceilings should be done with oil paints, floors are covered with materials that do not absorb liquids - linoleum, PVC plastic compound, etc.). All building structures in rooms where work with radioactive substances is carried out should not have cracks and discontinuities; the corners are rounded to prevent the accumulation of radioactive dust in them and to facilitate cleaning. At least once a month, a general cleaning of the premises is carried out with the obligatory washing of walls, windows, doors, furniture and equipment with hot soapy water. The current wet cleaning of the premises is carried out daily.

To reduce the exposure of personnel, all work with these sources is carried out using long grips or holders. Time protection consists in the fact that work with radioactive sources is carried out for such a period of time that the radiation dose received by the personnel does not exceed the maximum permissible level.

Collective means of protection against ionizing radiation are regulated by GOST 12.4.120-83 “Means of collective protection against ionizing radiation. General requirements". In accordance with this regulatory document, the main means of protection are stationary and mobile protective screens, containers for transporting and storing sources of ionizing radiation, as well as for collecting and transporting radioactive waste, protective safes and boxes, etc.

Stationary and mobile protective screens are designed to reduce the level of radiation in the workplace to an acceptable level. If work with sources of ionizing radiation is carried out in a special room - a working chamber, then its walls, floor and ceiling, made of protective materials, serve as screens. Such screens are called stationary. For the device of mobile screens, various shields are used that absorb or attenuate radiation.

Screens are made from various materials. Their thickness depends on the type of ionizing radiation, the properties of the protective material and the required radiation attenuation factor k. The value of k shows how many times it is necessary to reduce the energy indicators of radiation (exposure dose rate, absorbed dose, particle flux density, etc.) in order to obtain acceptable values of the listed characteristics. For example, for the case of absorbed dose, k is expressed as follows:

where D is the absorbed dose rate; D0 - acceptable level of absorbed dose.

For the construction of stationary means of protecting walls, ceilings, ceilings, etc. brick, concrete, barite concrete and barite plaster are used (they include barium sulfate - BaSO4). These materials reliably protect personnel from exposure to gamma and X-rays.

Various materials are used to create mobile screens. Protection against alpha radiation is achieved by using screens of ordinary or organic glass with a thickness of several millimeters. Sufficient protection against this type of radiation is a layer of air a few centimeters. To protect against beta radiation, screens are made of aluminum or plastic (organic glass). Lead, steel, tungsten alloys effectively protect against gamma and X-ray radiation. Viewing systems are made of special transparent materials, such as lead glass. Materials containing hydrogen (water, paraffin), as well as beryllium, graphite, boron compounds, etc. protect against neutron radiation. Concrete can also be used for neutron shielding.

Protective safes are used to store sources of gamma radiation. They are made from lead and steel.

Protective glove boxes are used to work with radioactive substances with alpha and beta activity.

Protective containers and collectors for radioactive waste are made of the same materials as screens - organic glass, steel, lead, etc.

When working with sources of ionizing radiation, the hazardous area must be limited by warning labels.

A hazardous zone is a space in which a worker can be exposed to hazardous and (or) harmful production factors (in this case, ionizing radiation).

The principle of operation of devices designed to monitor personnel exposed to ionizing radiation is based on various effects arising from the interaction of these radiations with a substance. The main methods for detecting and measuring radioactivity are gas ionization, scintillation and photochemical methods. The most commonly used ionization method is based on measuring the degree of ionization of the medium through which the radiation has passed.

Scintillation methods for detecting radiation are based on the ability of some materials, by absorbing the energy of ionizing radiation, to convert it into light radiation. An example of such a material is zinc sulfide (ZnS). The scintillation counter is a photoelectron tube with a window coated with zinc sulfide. When radiation enters this tube, a weak flash of light occurs, which leads to the appearance of electric current pulses in the photoelectron tube. These impulses are amplified and counted.

There are other methods for determining ionizing radiation, for example, calorimetric methods, which are based on measuring the amount of heat released during the interaction of radiation with an absorbing substance.

Dosimetric monitoring devices are divided into two groups: dosimeters used for quantitative measurement of dose rate, and radiometers or radiation indicators used for the rapid detection of radioactive contamination.

From domestic devices, for example, dosimeters of the DRGZ-04 and DKS-04 brands are used. The first is used to measure gamma and X-ray radiation in the energy range of 0.03-3.0 MeV. The instrument scale is graduated in microroentgen/second (μR/s). The second device is used to measure gamma and beta radiation in the energy range of 0.5-3.0 MeV, as well as neutron radiation (hard and thermal neutrons). The scale of the device is graduated in milliroentgens per hour (mR/h). The industry also produces household dosimeters intended for the population, for example, the household dosimeter "Master-1" (designed to measure the dose of gamma radiation), the household dosimeter-radiometer ANRI-01 ("Pine").

nuclear radiation lethal ionizing

Conclusion

So, from the above, we can conclude the following:

ionizing radiation- in the most general sense - various types of microparticles and physical fields capable of ionizing matter. The following types of ionizing radiation are most significant: short-wave electromagnetic radiation (X-ray and gamma radiation), fluxes of charged particles: beta particles (electrons and positrons), alpha particles (nuclei of the helium-4 atom), protons, other ions, muons, etc. . as well as neutrons. In nature, ionizing radiation is usually generated as a result of spontaneous radioactive decay of radionuclides, nuclear reactions (synthesis and induced fission of nuclei, capture of protons, neutrons, alpha particles, etc.), as well as during the acceleration of charged particles in space (the nature of such acceleration of cosmic particles up to the end is not clear).

Artificial sources of ionizing radiation are artificial radionuclides (generate alpha, beta and gamma radiation), nuclear reactors (generate mainly neutron and gamma radiation), radionuclide neutron sources, elementary particle accelerators (generate fluxes of charged particles, as well as bremsstrahlung photon radiation), x-ray machines (generate bremsstrahlung x-rays). Irradiation is very dangerous for the human body, the degree of danger depends on the dose (in my abstract I gave the maximum allowable norms) and the type of radiation - the safest is alpha radiation, and the more dangerous is gamma.

Ensuring radiation safety requires a complex of diverse protective measures, depending on the specific conditions of work with sources of ionizing radiation, as well as on the type of source.

Time protection is based on reducing the time of work with the source, which makes it possible to reduce personnel exposure doses. This principle is especially often used in the direct work of personnel with low radioactivity.

Distance protection is a fairly simple and reliable way of protection. This is due to the ability of radiation to lose its energy in interactions with matter: the greater the distance from the source, the more processes of interaction of radiation with atoms and molecules, which ultimately leads to a decrease in the radiation dose of personnel.

Shielding is the most effective way to protect against radiation. Depending on the type of ionizing radiation, various materials are used for the manufacture of screens, and their thickness is determined by power and radiation.

Literature

1. “Harmful chemicals. radioactive substances. Directory." Under total ed. L.A. Ilyina, V.A. Filov. Leningrad, "Chemistry". 1990.

2. Fundamentals of protection of the population and territories in emergency situations. Ed. acad. V.V. Tarasova. Moscow University Press. 1998.

3. Life safety / Ed. S.V. Belova.- 3rd ed., revised.- M .: Higher. school, 2001. - 485s.

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Main characteristic

Ionizing radiation is a kind of radiant energy that enters a specific environment, causing the process of ionization in the body. A similar characteristic of ionizing radiation is suitable for x-rays, radioactive and high energies, and much more.

Ionizing radiation has a direct effect on the human body. Despite the fact that ionizing radiation can be used in medicine, it is extremely dangerous, as evidenced by its characteristics and properties.

Known varieties are radioactive exposures, which appear due to the arbitrary splitting of the atomic nucleus, which causes the transformation of chemical and physical properties. Substances that can decay are considered radioactive.

They are artificial (seven hundred elements), natural (fifty elements) - thorium, uranium, radium. It should be noted that they have carcinogenic properties, toxins are released as a result of exposure to humans can cause cancer, radiation sickness.

It is necessary to note the following types of ionizing radiation that affect the human body:

Alpha

They are considered positively charged helium ions, which appear in the case of the decay of the nuclei of heavy elements. Protection from ionizing radiation is carried out using a paper sheet, cloth.

Beta

- a stream of negatively charged electrons that appear in the event of the decay of radioactive elements: artificial, natural. The damaging factor is much higher than that of the previous species. As protection, you need a thick screen, more durable. These radiations include positrons.

Gamma

- a hard electromagnetic oscillation that appears after the decay of the nuclei of radioactive substances. There is a high penetrating factor, which is the most dangerous radiation of the three listed for the human body. To shield the rays, you need to use special devices. This will require good and durable materials: water, lead and concrete.

x-ray

Ionizing radiation is formed in the process of working with a tube, complex installations. The characteristic resembles gamma rays. The difference lies in the origin, wavelength. There is a penetrating factor.

Neutron

Neutron radiation is a stream of uncharged neutrons, which are part of nuclei, except for hydrogen. As a result of irradiation, substances receive a portion of radioactivity. There is the largest penetrating factor. All these types of ionizing radiation are very dangerous.

Main sources of radiation

Sources of ionizing radiation are artificial, natural. Basically, the human body receives radiation from natural sources, these include:

terrestrial radiation;
internal irradiation.

As for the sources of terrestrial radiation, many of them are carcinogenic. These include:

Uranus;
potassium;
thorium;
polonium;
lead;
rubidium;
radon.

The danger is that they are carcinogenic. Radon is a gas that has no smell, color, taste. It is seven and a half times heavier than air. Its decay products are much more dangerous than gas, so the impact on the human body is extremely tragic.

Artificial sources include:

nuclear power;
enrichment factories;
uranium mines;
burial grounds with radioactive waste;
x-ray machines;
nuclear explosion;
scientific laboratories;
radionuclides that are actively used in modern medicine;
lighting devices;
computers and telephones;
Appliances.

In the presence of these sources nearby, there is a factor of the absorbed dose of ionizing radiation, the unit of which depends on the duration of exposure to the human body.

The operation of sources of ionizing radiation occurs daily, for example: when you work at a computer, watch a TV show or talk on a mobile phone, smartphone. All of these sources are to some extent carcinogenic, they can cause severe and fatal diseases.

The placement of sources of ionizing radiation includes a list of important, responsible work related to the development of a project for the location of irradiating installations. All radiation sources contain a certain unit of radiation, each of which has a certain effect on the human body. This includes manipulations carried out for installation, commissioning of these installations.

It should be pointed out that the disposal of sources of ionizing radiation is mandatory.

It is a process that helps to decommission generating sources. This procedure consists of technical, administrative measures that are aimed at ensuring the safety of personnel, the public, and there is also a factor in protecting the environment. Carcinogenic sources and equipment are a huge danger to the human body, so they must be disposed of.

Features of registration of radiation

The characteristic of ionizing radiation shows that they are invisible, they have no smell and color, so they are difficult to notice.

For this, there are methods for registering ionizing radiation. As for the methods of detection, measurement, everything is carried out indirectly, some property is taken as the basis.

The following methods for detecting ionizing radiation are used:

Physical: ionization, proportional counter, gas-discharge Geiger-Muller counter, ionization chamber, semiconductor counter.
Calorimetric detection method: biological, clinical, photographic, hematological, cytogenetic.
Fluorescent: Fluorescent and scintillation counters.
Biophysical method: radiometry, calculated.

Dosimetry of ionizing radiation is carried out with the help of devices that are able to determine the dose of radiation. The device includes three main parts - pulse counter, sensor, power supply. Radiation dosimetry is possible thanks to a dosimeter, a radiometer.

Influences on a person

The effect of ionizing radiation on the human body is especially dangerous. The following consequences are possible:

there is a factor of very deep biological change;
there is a cumulative effect of a unit of absorbed radiation;
the effect manifests itself over time, since a latent period is noted;
all internal organs, systems have different sensitivity to a unit of absorbed radiation;
radiation affects all offspring;
the effect depends on the unit of absorbed radiation, radiation dose, duration.

Despite the use of radiation devices in medicine, their effects can be detrimental. The biological effect of ionizing radiation in the process of uniform irradiation of the body, in the calculation of 100% of the dose, is the following:

bone marrow - a unit of absorbed radiation 12%;
lungs - at least 12%;
bones - 3%;
testicles, ovaries– the absorbed dose of ionizing radiation is about 25%;
thyroid gland– unit of absorbed dose is about 3%;
mammary glands - approximately 15%;
other tissues - the unit of absorbed radiation dose is 30%.

As a result, various diseases can occur up to oncology, paralysis and radiation sickness. It is extremely dangerous for children and pregnant women, as there is an abnormal development of organs and tissues. Toxins, radiation - sources of dangerous diseases.

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