Today even small children are aware of the existence of invisible deadly rays. They scare us from computer and TV screens dire consequences radiation: post-apocalyptic films and games are still fashionable. However, only a few can give a clear answer to the question “what is radiation?” And further less people realize how real the threat of radiation exposure is. Moreover, not somewhere in Chernobyl or Hiroshima, but in his own home.
What is radiation?
In fact, the term "radiation" does not necessarily mean "deadly rays." Thermal or, for example, solar radiation poses virtually no threat to the life and health of living organisms living on the surface of the Earth. Of all known types of radiation real danger represents only ionizing radiation, which physicists also call electromagnetic or corpuscular. This is the very “radiation” whose dangers are talked about on TV screens.
Ionizing gamma and x-ray radiation- that “radiation” that they talk about on TV screens
Peculiarity ionizing radiation is that, unlike other types of radiation, it has exceptionally high energy and, when interacting with matter, causes the ionization of its molecules and atoms. Particles of a substance that were electrically neutral before irradiation are excited, resulting in the formation of free electrons, as well as positively and negatively charged ions.
The four most common types of ionizing radiation are alpha, beta, gamma, and x-rays (has the same properties as gamma). They consist of different particles, and therefore have different energies and, accordingly, different penetrating abilities. The “weakest” in this sense is alpha radiation, which is a stream of positively charged alpha particles, unable to “leak through” even through an ordinary sheet of paper (or human skin). Beta radiation, consisting of electrons, penetrates the skin already by 1-2 cm, but it is quite possible to protect yourself from it. But there is practically no escape from gamma radiation: high-energy photons (or gamma quanta) can only be stopped by a thick lead or reinforced concrete wall. However, the fact that alpha and beta particles can be easily stopped even by a minor barrier like paper does not mean that they will not enter the body. The respiratory organs, microtraumas on the skin and mucous membranes are “open gates” for radiation with low penetrating ability.
Units of measurement and norm of radiation
The main measure of radiation exposure is considered to be exposure dose. It is measured in P (roentgens) or derivatives (mR, μR) and represents the total amount of energy that the source of ionizing radiation managed to transfer to an object or organism during the irradiation process. Since different types of radiation have different degrees of danger with the same amount of transmitted energy, it is customary to calculate another indicator - the equivalent dose. It is measured in B (rem), Sv (sieverts) or their derivatives and is calculated as the product of the exposure dose by a coefficient characterizing the quality of radiation (for beta and gamma radiation the quality coefficient is 1, for alpha - 20). To assess the strength of the ionizing radiation itself, other indicators are used: exposure and equivalent dose power (measured in R/sec or derivatives: mR/sec, μR/hour, mR/hour), as well as flux density (measured in (cm 2 min) -1) for alpha and beta radiation.
Today it is generally accepted that ionizing radiation with a dose rate below 30 μR/hour is absolutely safe for health. But everything is relative... As recent studies have shown, different people have different resistance to the effects of ionizing radiation. Approximately 20% have hypersensitivity, the same amount - reduced. The consequences of low-dose radiation usually appear years later or do not appear at all, affecting only the descendants of the person affected by radiation. So, the safety of small doses (slightly exceeding the norm) still remains one of the most discussed issues.
Radiation and man
So, what is the effect of radiation on the health of humans and other living beings? As already noted, ionizing radiation in various ways penetrates the body and causes ionization (excitation) of atoms and molecules. Further, under the influence of ionization, free radicals are formed in the cells of a living organism, which disrupt the integrity of proteins, DNA, RNA and other complex biological compounds. Which in turn leads to mass death cells, carcinogenesis and mutagenesis.
In other words, the effect of radiation on the human body is destructive. With strong radiation Negative consequences appear almost immediately: high doses cause radiation sickness of varying degrees of severity, burns, blindness, and the occurrence of malignant neoplasms. But small doses, until recently considered “harmless”, are no less dangerous (today everyone comes to this conclusion larger number researchers). The only difference is that the effects of radiation do not appear immediately, but after several years, sometimes decades. Leukemia, cancerous tumors, mutations, deformities, disorders of the gastrointestinal tract, circulatory system, mental and mental development, schizophrenia - these are far from full list diseases that can cause low doses of ionizing radiation.
Even small amounts of radiation can lead to catastrophic consequences. But radiation is especially dangerous for young children and the elderly. Thus, according to specialists on our website www.site, the likelihood of leukemia occurring during low-dose irradiation increases by 2 times for children under 10 years of age and 4 times for infants who were in the womb at the time of irradiation. Radiation and health are literally incompatible!
Radiation protection
A characteristic feature of radiation is that it does not “dissolve” in environment, like harmful chemical compounds. Even after eliminating the radiation source, the background for a long time remains elevated. Therefore, there is a clear and unambiguous answer to the question “how to deal with radiation?” still doesn't exist. It is clear that in case nuclear war(for example) invented special means protection against radiation: special suits, bunkers, etc. But this is for “emergency situations”. But what about small doses, which many still consider “virtually safe”?
It is known that “saving drowning people is the work of the drowning people themselves.” While researchers are deciding which dose should be considered dangerous and which should not, it is better to buy a device that measures radiation yourself and walk around territories and objects a mile away, even if they “radiate” quite a bit (at the same time, the question “how to recognize radiation?” will be resolved, because With a dosimeter in hand, you will always be aware of the surrounding background). Moreover, in modern city radiation can be found in any, even the most unexpected places.
And finally, a few words about how to remove radiation from the body. To speed up cleansing as much as possible, doctors recommend:
1. Physical activity, bath and sauna - speed up metabolism, stimulate blood circulation and, therefore, help remove any harmful substances from the body naturally.
2. Healthy eating— special attention should be paid to vegetables and fruits rich in antioxidants (this is the diet prescribed to cancer patients after chemotherapy). Entire “deposits” of antioxidants are found in blueberries, cranberries, grapes, rowan berries, currants, beets, pomegranates and other sour and sweet-sour fruits of red shades.
“People’s attitude towards a particular danger is determined by how well they know it.”
This material is a generalized answer to numerous questions that arise from users of devices for detecting and measuring radiation in domestic conditions.
Minimal use of specific terminology of nuclear physics when presenting 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 natural radioactive elements discovered was called radium.”
- translated from Latin - emitting rays, radiating.”
Each person in the environment is exposed to various phenomena that influence him. These include heat, cold, magnetic and ordinary storms, heavy rains, heavy snowfalls, strong winds, sounds, explosions, etc.
Thanks to the presence of sensory organs assigned to him by nature, he can quickly respond to these phenomena with the help of, for example, a sun canopy, clothing, shelter, medicine, 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 accompanying radiation (so-called ionizing) have always existed in the Universe. Radioactive materials are part of the Earth and even humans are slightly radioactive, because... Radioactive substances are present in the smallest quantities in any living tissue.
The most unpleasant property of radioactive (ionizing) radiation is its effect on the tissues of a living organism, therefore appropriate measuring instruments that would provide timely information to make useful decisions before the long time and undesirable or even disastrous consequences will appear. That a person will not begin to feel its impact 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.
However, enough of the mysteries. Let's talk about what radiation and ionizing (i.e. radioactive) radiation are.
Ionizing radiation
Any medium consists of tiny neutral particles - atoms, which consist of positively charged nuclei and negatively charged electrons surrounding them. Every atom is like solar system in miniature: “planets” move in orbit around a tiny core - electrons.
Atomic nucleus consists of several elementary particles-protons and neutrons held by nuclear forces.
Protons particles having a positive charge equal in absolute value to the charge of electrons.
Neutrons neutral particles with no charge. The number of electrons in an atom is exactly equal to the number of protons in the nucleus, so each atom is generally neutral. The mass of a proton is almost 2000 times more mass electron.
The number of neutral particles (neutrons) present in the nucleus can be different if the number of protons is the same. Such atoms having nuclei with the same number protons, but differing in the number of neutrons, belong to varieties of the same chemical element, called “isotopes” of a given element. To distinguish them from each other, a number equal to the sum of all particles in the nucleus is assigned to the element symbol of a given isotope. 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 the uranium atom - 238. From time to time, a compact group of four particles breaks out of it: two protons and two neutrons - an “alpha particle (alpha)”. Uranium-238 thus turns 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 (beta) moving in their orbits: 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 on average decreases by half.
With each act of decay, energy is released, which is transmitted in the form of radiation. Often an unstable nuclide finds itself in an excited state, and the emission of a particle does not lead to complete removal of excitation; then it emits a portion of energy in the form of gamma radiation (gamma quantum). As in the case x-rays(differing from gamma radiation only in frequency) in this case no particles are emitted. The entire process of spontaneous decay of an unstable nuclide is called radioactive decay, and the nuclide itself is called a radionuclide.
Various types of radiation are accompanied by the release different quantities energy and have different penetrating abilities; therefore, they have different effects on the tissues of a living organism. Alpha radiation is blocked, 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 with inhaled air or steam, for example, in a bath; then they become extremely dangerous. The beta particle has greater penetrating ability: it penetrates the body tissue to a depth of one to two centimeters or more, depending on the amount of energy. The penetrating power of gamma radiation, which travels at the speed of light, is very high: only a thick lead or concrete slab can stop it. Ionizing radiation is characterized by a number of measurable physical quantities. These should include energy quantities. At first glance, it may seem that they are sufficient for recording and assessing the impact of ionizing radiation on living organisms and humans. However, these energy values do not reflect physiological effects ionizing radiation on the human body and other living tissues are subjective, and for different people are different. Therefore, average values are used.
Sources of radiation can be natural, present in nature, and independent of humans.
It has been established that of all natural sources of radiation, radon poses the greatest danger. -heavy gas tasteless, odorless and invisible; with its subsidiary products.
Radon is released from earth's crust everywhere, but its concentration in the outside air varies significantly for different points globe. Paradoxical as it may seem at first glance, a person receives the main radiation from radon while in a closed, unventilated room. Radon concentrates in indoor air only when they are sufficiently insulated from external environment. Seeping through the foundation and floor from the soil or, less commonly, being released from building materials, radon accumulates indoors. Sealing rooms for the purpose of insulation only aggravates the matter, since it makes it even more difficult to escape radioactive gas from the premises. The problem of radon is especially important for low-rise buildings with careful sealing of rooms (in order to retain 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 greater specific radioactivity.
Another, usually less important, source of radon entering premises is water and natural gas, used for cooking and heating homes.
The concentration of radon in commonly used water is extremely low, but water from deep wells or artesian wells contains very high levels of radon. However, the main danger does not come from drinking water, even with a high radon content. Typically people consume most water in food and in the form of hot drinks, and when boiling water or cooking hot dishes, radon almost completely evaporates. A much greater danger is the ingress of water vapor with a high radon content into the lungs along with inhaled air, which most often occurs in the bathroom or steam room (steam room).
Radon enters natural gas underground. As a result of preliminary processing and during the storage of gas before it reaches the consumer, most of the radon evaporates, but the concentration of radon in the room can increase noticeably if kitchen stoves and other heating gas appliances are not equipped with an exhaust hood. In the presence of supply and exhaust ventilation, which communicates with the outside air, radon concentration does not occur in these cases. This also applies to the house as a whole - based on the readings of radon detectors, you can set a ventilation mode for the premises that completely eliminates the threat to health. However, given that the release of radon from the soil is seasonal, it is necessary to monitor the effectiveness of ventilation three to four times a year, avoiding exceeding the radon concentration standards.
Other sources of radiation, which unfortunately have potential dangers, are created by man himself. Sources artificial radiation- These 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 its dangerous nature for humans, radiation can be used to serve humans. 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.
Tests stand out in their impact on humans 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, type Chernobyl accident, can have an uncontrollable effect 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. It is very simple to protect yourself and your loved ones from this danger. When buying milk, vegetables, fruits, herbs, and any other products, it is not superfluous to turn on the dosimeter and bring it to the purchased product. 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 a handkerchief Toothbrush, soap.
IMPACT OF IONIZING RADIATION ON BODY TISSUE
The damage caused in a living organism by ionizing radiation will be 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 located outside the body or inside it.
The amount of radiation energy absorbed by irradiated body tissues, 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 for 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, for the same equivalent dose of radiation, cancer is more likely to occur in the lungs than in the thyroid gland, and irradiation of the gonads is especially dangerous due to the risk of genetic damage. Therefore, human radiation doses should be taken into account different coefficients. By multiplying the equivalent doses by the corresponding coefficients and summing them over all organs and tissues, we obtain an effective equivalent dose, reflecting the total effect of radiation on the body; it is also measured in Sieverts.
Charged particles.
Alpha and beta particles penetrating into body tissues lose energy due to electrical interactions with the electrons of the atoms near which they pass. (Gamma rays and X-rays transfer their energy to matter in several ways, which ultimately also lead to electrical interactions.)
Electrical interactions.
Within a time of about ten trillionths of a second after the penetrating radiation reaches the corresponding atom in the tissue of the body, an electron is torn off 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.
Physico-chemical changes.
Both the free electron and the ionized atom usually cannot remain in this state for long and, over the next ten billionths of a second, participate in a complex chain of reactions that result in the formation of new molecules, including such extremely reactive ones as “free radicals.”
Chemical changes.
Over the next millionths of a second, the resulting free radicals 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 within seconds or decades after irradiation and cause immediate cell death or changes in them.
UNITS OF MEASUREMENT OF RADIOACTIVITY |
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Becquerel (Bq, Bq); |
1 Bq = 1 decay per second. |
Units of radionuclide activity. Represent the number of decays per unit time. |
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Gray (Gr, Gu); |
1 Gy = 1 J/kg |
Absorbed dose units. Represent the amount of energy of ionizing radiation absorbed by a unit of mass of any physical body, for example, body tissues. |
|
Sievert (Sv, Sv) |
1 Sv = 1 Gy = 1 J/kg (for beta and gamma) 1 µSv = 1/1000000 Sv 1 ber = 0.01 Sv = 10 mSv Equivalent dose units. |
Equivalent dose units. They represent a unit of absorbed dose multiplied by a coefficient that takes into account the unequal danger of different types of ionizing radiation. |
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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. They represent the dose received by the body per unit of time. |
For information, and not to intimidate, especially people who decide to devote themselves to working with ionizing radiation, you should know the maximum permissible doses. The units of measurement of radioactivity are given in Table 1. According to the conclusion International Commission By radiation protection as of 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 radiation exposure exceeds a certain threshold, radiation sickness occurs. There are chronic and acute (with a single massive exposure) forms of this disease. Acute radiation sickness is divided into four degrees by 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). Stage 4 can be fatal.
The 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).
For medical diagnostic procedures - x-rays, etc. - a person receives approximately another 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 emissions from modern coal-fired thermal power plants and when flying on an airplane, a person receives up to 4 mSv/year. In total, the 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 reserve. For personnel working with sources of ionizing radiation, the maximum permissible dose is set at 50 mSv/year (5 rem/year), i.e. 28 µSv/h with a 36-hour work week.
According to hygienic standards NRB-96 (1996) permissible levels dose rate for external irradiation of the whole body from man-made sources for permanent residence of personnel - 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).
HOW DO YOU MEASURE RADIATION?
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 by a solid), scintillation, luminescent, photographic. These methods form the basis of the work dosimeters radiation. Gas-filled ionizing radiation sensors include ionization chambers, fission chambers, proportional counters, and Geiger-Muller counters. The latter are relatively simple, the cheapest, and not critical to operating 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 that enters the sensitive volume of the counter causes self-discharge. Precisely falling into the 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 overcome the body of the device, and will not fall into sensing element and will not be detected.
Doctor of Physical and Mathematical Sciences, Professor at MEPhI N.M. Gavrilov
The article was written for the company "Kvarta-Rad"
Radiation is a stream of particles produced during nuclear reactions or radioactive decay. We have all heard about the danger of radioactive radiation for human body and we know that it can cause a huge number of pathological conditions. But often most people do not know what exactly the dangers of radiation are and how they can protect themselves from it. In this article we looked at what radiation is, what its danger is to humans, and what diseases it can cause.
What is radiation
The definition of this term is not very clear to a person not connected with physics or, for example, medicine. The term “radiation” refers to the release of particles produced during nuclear reactions or radioactive decay. That is, this is radiation that comes out of certain substances.
Radioactive particles have different ability penetration and passage through various substances. Some of them can pass through glass, human body, concrete.
Radiation protection rules are based on knowledge of the ability of specific radioactive waves to pass through materials. For example, the walls of X-ray rooms are made of lead, through which radioactive radiation cannot pass.
Radiation happens:
- natural. It forms natural background radiation, to which we are all accustomed. The sun, soil, stones emit radiation. They are not dangerous to the human body.
- technogenic, that is, one that was created as a result of human activity. This includes mining radioactive substances from the depths of the Earth, use nuclear fuels, reactors, etc.
How radiation enters the human body
Acute radiation sickness
This condition develops with a single massive exposure to human radiation.. This condition is rare.
It can develop during some man-made accidents and disasters.
Degree clinical manifestations depends on the amount of radiation affecting the human body.
In this case, all organs and systems can be affected.
Chronic radiation sickness
This condition develops with prolonged contact with radioactive substances.. Most often it develops in people who interact with them on duty.
Wherein clinical picture may grow slowly over many years. With prolonged and prolonged contact with radioactive sources Irradiation damages the nervous, endocrine, and circulatory systems. The kidneys also suffer, and failures occur in all metabolic processes.
Chronic radiation sickness has several stages. It can occur polymorphically, clinically manifested by damage to various organs and systems.
Oncological malignant pathologies
Scientists have proven that radiation can provoke cancer pathologies. Most often skin cancer develops or thyroid gland, there are also frequent cases of leukemia - blood cancer in people suffering from acute radiation sickness.
According to statistics, the number of oncological pathologies after the accident in Chernobyl nuclear power plant increased tenfold in areas affected by radiation.
Use of radiation in medicine
Scientists have learned to use radiation for the benefit of humanity. A huge number of different diagnostic and therapeutic procedures are related in one way or another to radioactive radiation. Thanks to sophisticated safety protocols and state-of-the-art equipment this use of radiation is practically safe for the patient and medical personnel, but subject to all safety rules.
Diagnostic medical techniques using radiation: radiography, computed tomography, fluorography.
Treatment methods include various types of radiation therapy, which are used in the treatment of oncological pathologies.
The use of radiation diagnostic methods and therapy should be carried out by qualified specialists. These procedures are prescribed to patients solely for indications.
Basic methods of protection against radiation radiation
Having learned to use radioactive radiation in industry and medicine, scientists took care of the safety of people who may come into contact with these dangerous substances.
Only careful adherence to the basics of personal prevention and protection from radiation can protect a person working in a dangerous radioactive zone from chronic radiation sickness.
Basic methods of protection against radiation:
- Protection through distance. Radioactive radiation has a certain wavelength beyond which it has no effect. That's why in case of danger, you must immediately leave the danger zone.
- Shielding protection. The essence of this method is to use substances for protection that do not allow radioactive waves to pass through them. For example, paper, a respirator, and rubber gloves can protect against alpha radiation.
- Time protection. All radioactive substances have a half-life and decay time.
- Chemical protection. Substances that can reduce the negative effects of radiation on the body are given to a person orally or injected.
People working with radioactive substances have protocols for protection and behavior in different situations. Usually, dosimeters are installed in the work areas - devices for measuring background radiation.
Radiation is dangerous for humans. When its level increases above the permissible norm, various diseases and damage to internal organs and systems. Against the background of radiation exposure, malignant oncological pathologies can develop. Radiation is also used in medicine. It is used to diagnose and treat many diseases.
A little theory
Radioactivity is the instability of the nuclei of some atoms, which manifests itself in their ability to undergo spontaneous transformation (in scientific terms, decay), which is accompanied by the release of ionizing radiation (radiation).
The energy of such radiation is quite high, so it is capable of influencing matter, creating new ions of different signs. Cause radiation using chemical reactions You can’t, it’s a completely physical process.
There are several types of radiation
- Alpha particles are relatively heavy particles, positively charged, and are helium nuclei.
- Beta particles are ordinary electrons.
- Gamma radiation - has the same nature as visible light, however, much greater penetrating power.
- Neutrons are electrically neutral particles that occur mainly in the vicinity of the working nuclear reactor, access there should be limited.
- X-rays are similar to gamma rays, but have less energy. By the way, the Sun is one of the natural sources of such rays, but protection from solar radiation provided by the Earth's atmosphere.
The most dangerous radiation for humans is Alpha, Beta and Gamma radiation, which can lead to serious illnesses, genetic disorders and even death.
The extent to which radiation affects human health depends on the type of radiation, time and frequency. Thus, the consequences of radiation, which can lead to fatal cases, occur both during a single stay at the strongest source of radiation (natural or artificial), and when storing weakly radioactive objects at home (antiques, precious stones treated with radiation, products made from radioactive plastic) .
Charged particles are very active and interact strongly with matter, so even one alpha particle can be enough to destroy a living organism or damage a huge number of cells. However, for the same reason, any layer of solid or liquid substance, for example, ordinary clothes.
According to experts, ultraviolet radiation or laser radiation cannot be considered radioactive.
What is the difference between radiation and radioactivity?
Sources of radiation are nuclear facilities (particle accelerators, reactors, X-ray equipment) and radioactive substances. They can exist for a considerable time without manifesting themselves in any way, and you may not even suspect that you are near an object of extreme radioactivity.
Units of measurement of radioactivity
Radioactivity is measured in Becquerels (BC), which corresponds to one decay per second. The content of radioactivity in a substance is also often estimated per unit of weight - Bq/kg, or volume - Bq/cub.m.
Sometimes there is such a unit as Curie (Ci). This is a huge value, equal to 37 billion Bq. When a substance decays, the source emits ionizing radiation, the measure of which is the exposure dose. It is measured in Roentgens (R). 1 Roentgen is a fairly large value, so in practice a millionth (µR) or thousandth (mR) fraction of a Roentgen is used.
Household dosimeters measure ionization for certain time, that is, not the exposure dose itself, but its power. The unit of measurement is microroentgen per hour. It is this indicator that is most important for a person, as it allows one to assess the danger of a particular radiation source.
Radiation and human health
The effect of radiation on the human body is called irradiation. During this process, radiation energy is transferred to the cells, destroying them. Radiation can cause all sorts of diseases - infectious complications, metabolic disorders, malignant tumors and leukemia, infertility, cataracts and much more. Radiation has a particularly acute effect on dividing cells, so it is especially dangerous for children.
The body reacts to the radiation itself, and not to its source. Radioactive substances can enter the body through the intestines (with food and water), through the lungs (by breathing) and even through the skin during medical diagnostics using radioisotopes. In this case, internal exposure occurs.
In addition, external radiation has a significant impact on the human body, i.e. The source of radiation is outside the body. The most dangerous, of course, is internal radiation.
How to remove radiation from the body
This question certainly worries many. Unfortunately, especially effective and quick ways There is no removal of radionuclides from the human body. Certain foods and vitamins help cleanse the body of small doses of radiation. But if the radiation exposure is serious, then we can only hope for a miracle. Therefore, it is better not to take risks. And if there is even the slightest danger of being exposed to radiation, it is necessary to move your feet out of the area as quickly as possible. dangerous place and call specialists.
Is the computer a source of radiation?
This question, in the age of the spread of computer technology, worries many. The only part of the computer that could theoretically be radioactive is the monitor, and even then, only electro-beam. Modern displays, liquid crystal and plasma, do not have radioactive properties.
CRT monitors, like televisions, are a weak source of X-ray radiation. It occurs on inner surface screen glass, however, due to the significant thickness of the same glass, it absorbs most of the radiation. To date, no health effects have been found from CRT monitors. However, with the widespread use of liquid crystal displays, this issue is losing its former relevance.
Can a person become a source of radiation?
Radiation, affecting the body, does not form radioactive substances in it, i.e. a person does not turn into a source of radiation. By the way, X-rays, contrary to popular belief, are also safe for health. Thus, unlike illness, radiation injury cannot be transmitted from person to person, but radioactive objects, which carry a charge, can be dangerous.
Radiation level measurement
You can measure the level of radiation using a dosimeter. Household appliances are simply irreplaceable for those who want to protect themselves as much as possible from fatal dangerous influence radiation.
The main purpose of a household dosimeter is to measure the radiation dose rate in the place where a person is located, to examine certain objects (cargo, building materials, money, food, children's toys). Buying a device that measures radiation is simply necessary for those who often visit areas of radiation pollution caused by the accident at the Chernobyl nuclear power plant (and such hot spots are present in almost all areas European territory Russia).
The dosimeter will also help those who are in an unfamiliar area, far from civilization - on a hike, picking mushrooms and berries, or hunting. It is imperative to inspect for radiation safety the site of the proposed construction (or purchase) of a house, cottage, garden or land plot, otherwise, instead of benefit, such a purchase will only bring deadly diseases.
It is almost impossible to clean food, soil or objects from radiation, so the only way to protect yourself and your family is to stay away from them. Namely, a household dosimeter will help identify potentially dangerous sources.
Radioactivity standards
Regarding radioactivity exists big number norms, i.e. They try to standardize almost everything. Another thing is that dishonest sellers, in pursuit of big profits, do not comply with, and sometimes even openly violate, the norms established by law.
The basic standards established in Russia are set out in Federal law No. 3-FZ dated December 5, 1996 "On radiation safety population" and in Sanitary rules 2.6.1.1292-03 "Radiation safety standards".
For inhaled air, water and food products, the content of both man-made (obtained as a result of human activity) and natural radioactive substances is regulated, which should not exceed the standards established by SanPiN 2.3.2.560-96.
In building materials, the content of radioactive substances of the thorium and uranium family, as well as potassium-40, is standardized; their specific effective activity is calculated using special formulas. Requirements for building materials are also specified in GOST.
In premises, the total content of thoron and radon in the air is regulated - for new buildings it should be no more than 100 Bq (100 Bq/m3), and for those already in use - less than 200 Bq/m3. In Moscow, additional standards MGSN2.02-97 are also applied, which regulate the maximum permissible levels of ionizing radiation and radon content in building areas.
For medical diagnostics, dose limits are not indicated, but requirements are put forward for minimum sufficient levels of exposure to obtain high-quality diagnostic information.
In computer technology, the maximum radiation level for electro-ray (CRT) monitors is regulated. The X-ray dose rate at any point at a distance of 5 cm from a video monitor or personal computer should not exceed 100 µR per hour.
The level of radiation safety can only be reliably checked using a personal household dosimeter.
You can only check whether manufacturers comply with the statutory standards yourself, using a miniature household dosimeter. It is very simple to use, just press one button and check the readings on the liquid crystal display of the device with the recommended ones. If the norm is significantly exceeded, it means this item poses a threat to life and health and should be reported to the Ministry of Emergency Situations so that it can be destroyed.
How to protect yourself from radiation
Everyone is well aware of the high level of radiation danger, but the question of how to protect yourself from radiation is becoming increasingly urgent. You can protect yourself from radiation by time, distance and substance.
It is advisable to protect yourself from radiation only when its doses are tens or hundreds of times higher than the natural background. In any case, there must be fresh vegetables, fruits, and herbs on your table. According to doctors, even with a balanced diet, the body is only half provided with essential vitamins and minerals, which is responsible for the increase in oncological diseases.
As our research has shown, effective protection Selenium is used against radiation in small and medium doses, as well as in reducing the risk of tumor development. It is found in wheat, white bread, cashew nuts, radishes, but in small doses. It is much more effective to take biologically prescribed by your doctor active additives with this element.
Time protection
The shorter the time spent near a radiation source, the lower the radiation dose a person receives. Short-term contact with even the most powerful X-ray radiation during medical procedures will not cause much harm, but if the X-ray machine is left for a longer period, it will simply “burn” living tissue.
Defence from different types radiation shielding
Protection by distance is that the radiation decreases with distance from the compact source. That is, if at a distance of 1 meter from a radiation source the dosimeter shows 1000 microroentgens per hour, then at a distance of 5 meters it shows about 40 microroentgens per hour, which is why radiation sources are often so difficult to detect. At long distances they are not “caught”; you need to clearly know the place where to look.
Substance protection
It is necessary to strive to ensure that there is as much substance as possible between you and the source of radiation. The denser it is and the more of it there is, the greater the portion of radiation that it can absorb.
Speaking about the main source of radiation in rooms - radon and its decay products, it should be noted that radiation can be significantly reduced by regular ventilation.
You can protect yourself from alpha radiation with a regular sheet of paper, a respirator and rubber gloves; for beta radiation you will already need a thin layer of aluminum, glass, a gas mask and plexiglass; to combat gamma radiation they are effective heavy metals such as steel, lead, tungsten, cast iron, and water and polymers such as polyethylene can save you from neutrons.
When building a house or interior decoration, it is recommended to use radiation safe materials. Thus, houses made of wood and timber are much safer in terms of radiation than brick ones. Sand-lime bricks are smaller than bricks made from clay. Manufacturers have invented a special labeling system that emphasizes environmental safety their materials. If you are concerned about the safety of future generations, choose these.
There is an opinion that alcohol can protect against radiation. There is some truth in this, alcohol reduces susceptibility to radiation, but modern anti-radiation drugs are much more reliable.
To know exactly when to be wary of radioactive substances, we recommend purchasing a radiation dosimeter. This small device will always warn you if you find yourself close to a radiation source, and you will have time to choose the most appropriate method of protection.
Ionizing radiation (hereinafter referred to as IR) is radiation whose interaction with matter leads to the ionization of atoms and molecules, i.e. this interaction leads to the excitation of the atom and the removal of individual electrons (negatively charged particles) from atomic shells. As a result, deprived of one or more electrons, the atom turns into a positively charged ion - primary ionization occurs. AI includes electromagnetic radiation(gamma radiation) and flows of charged and neutral particles - corpuscular radiation (alpha radiation, beta radiation, and neutron radiation).
Alpha radiation refers to corpuscular radiation. This is a stream of heavy positively charged alpha particles (nuclei of helium atoms) resulting from the decay of atoms of heavy elements such as uranium, radium and thorium. Since the particles are heavy, the range of alpha particles in a substance (that is, the path along which they produce ionization) turns out to be very short: hundredths of a millimeter in biological media, 2.5-8 cm in air. Thus, a regular sheet of paper or the outer dead layer of skin can trap these particles.
However, substances that emit alpha particles are long-lived. As a result of such substances entering the body with food, air or through wounds, they are carried throughout the body by the bloodstream, deposited in organs responsible for metabolism and protection of the body (for example, the spleen or lymph nodes), thus causing internal irradiation of the body . The danger of such internal irradiation of the body is high, because these alpha particles create a very large number of ions (up to several thousand pairs of ions per 1 micron of path in tissues). Ionization, in turn, determines a number of features of those chemical reactions that occur in matter, in particular in living tissue (the formation of strong oxidizing agents, free hydrogen and oxygen, etc.).
Beta radiation(beta rays, or stream of beta particles) also refers to the corpuscular type of radiation. This is a stream of electrons (β- radiation, or, most often, just β-radiation) or positrons (β+ radiation) emitted during the radioactive beta decay of the nuclei of certain atoms. Electrons or positrons are produced in the nucleus when a neutron converts to a proton or a proton to a neutron, respectively.
Electrons are significantly smaller than alpha particles and can penetrate 10-15 centimeters deep into a substance (body) (cf. hundredths of a millimeter for alpha particles). When passing through matter, beta radiation interacts with the electrons and nuclei of its atoms, expending its energy on this and slowing down the movement until it stops completely. Due to these properties, to protect against beta radiation, it is enough to have an organic glass screen of appropriate thickness. The use of beta radiation in medicine for superficial, interstitial and intracavitary radiation therapy is based on these same properties.
Neutron radiation- another type of corpuscular type of radiation. Neutron radiation is a flow of neutrons (elementary particles that do not have electric charge). Neutrons have no effect ionizing action, however, a very significant ionizing effect occurs due to elastic and inelastic scattering on the nuclei of matter.
Substances irradiated by neutrons can acquire radioactive properties, that is, receiving so-called induced radioactivity. Neutron radiation is generated during the operation of particle accelerators, in nuclear reactors, industrial and laboratory installations, when nuclear explosions etc. Neutron radiation has the greatest penetrating power. The best materials for protection against neutron radiation are hydrogen-containing materials.
Gamma rays and x-rays belong to electromagnetic radiation.
The fundamental difference between these two types of radiation lies in the mechanism of their occurrence. X-ray radiation is of extranuclear origin, gamma radiation is a product of nuclear decay.
X-ray radiation was discovered in 1895 by the physicist Roentgen. This is invisible radiation capable of penetrating, although varying degrees, in all substances. It is electromagnetic radiation with a wavelength of the order of - from 10 -12 to 10 -7. The source of X-rays is an X-ray tube, some radionuclides (for example, beta emitters), accelerators and electron storage devices (synchrotron radiation).
The X-ray tube has two electrodes - the cathode and the anode (negative and positive electrodes, respectively). When the cathode is heated, electron emission occurs (the phenomenon of the emission of electrons by the surface of a solid or liquid). Electrons escaping from the cathode are accelerated by the electric field and strike the surface of the anode, where they are sharply decelerated, resulting in X-ray radiation. Like visible light, X-rays cause photographic film to turn black. This is one of its properties, fundamental for medicine - that it is penetrating radiation and, accordingly, the patient can be illuminated with its help, and since tissues of different densities absorb x-rays differently - we can diagnose this on our own early stage many types of diseases of internal organs.
Gamma radiation is of intranuclear origin. It occurs during the decay of radioactive nuclei, the transition of nuclei from an excited state to the ground state, during the interaction of fast charged particles with matter, the annihilation of electron-positron pairs, etc.
The high penetrating power of gamma radiation is explained by its short wavelength. To weaken the flow of gamma radiation, substances with a significant mass number (lead, tungsten, uranium, etc.) and various compositions are used high density(various concretes with metal fillers).