Electromagnetic fields surround us everywhere. Depending on their wavelength range, they can act in different ways on living organisms. Non-ionizing radiation is considered to be more gentle, however, they are sometimes unsafe. What are these phenomena, and what effect do they have on our body?

What is Non-Ionizing Radiation?

Energy travels in the form of small particles and waves. The process of its emission and propagation is called radiation. By the nature of the impact on objects and living tissues, two main types are distinguished. The first - ionizing, is a stream of elementary particles that are formed as a result of the fission of atoms. It includes radioactive, X-ray, gravitational radiation and Hawking rays.

The second includes non-ionizing radiation. In fact, it is electromagnetic which is more than 1000 nm, and the amount of released energy is less than 10 keV. It acts in the form of microwaves, producing light and heat as a result.

Unlike the first type, this radiation does not ionize the molecules and atoms of the substance it affects, that is, it does not break the bonds between its molecules. Of course, there are some exceptions here. So, certain types, for example, UV rays, can ionize a substance.

Types of non-ionizing radiation

Electromagnetic radiation is a much broader concept than non-ionizing radiation. High-frequency X-rays and gamma rays are also electromagnetic, but they are harsher and ionize matter. All other types of EMP are non-ionizing, their energy is not enough to interfere with the structure of matter.

The longest among them are radio waves, whose range ranges from ultra-long (more than 10 km) to ultra-short (10 m - 1 mm). The waves of other EM radiation are less than 1 mm. After radio emission is infrared or thermal, its wavelength depends on the heating temperature.

Visible light is also non-ionizing, and the former is often called optical. With its spectrum, it is very close to infrared rays and is formed when bodies are heated. Ultraviolet radiation is close to X-ray, therefore, it can have the ability to ionize. At wavelengths between 400 and 315 nm, it is recognized by the human eye.

Sources of

Non-ionizing electromagnetic radiation can be of both natural and artificial origin. One of the main natural sources is the Sun. It sends out all kinds of radiation. Their complete penetration into our planet is hindered by the earth's atmosphere. Thanks to the ozone layer, humidity, carbon dioxide, the effect of harmful rays is greatly mitigated.

Lightning can be a natural source for radio waves, as well as space objects. Thermal infrared rays can be emitted by any body heated to the required temperature, although the main radiation comes from artificial objects. So, its main sources are heaters, burners and ordinary incandescent bulbs, which are present in every home.

Influence on a person

Electromagnetic radiation is characterized by wavelength, frequency and polarization. The strength of its impact depends on all these criteria. The longer the wave, the less energy it transfers to the object, which means it is less harmful. Radiation in the decimeter-centimeter range has the most destructive effect.

Non-ionizing radiation can be harmful to health when exposed to humans for a long time, although they can be beneficial in moderate doses. can cause burns to the skin and eye cornea, cause various mutations. And in medicine, they are used to synthesize vitamin D3 in the skin, sterilize equipment, disinfect water and air.

In medicine, infrared radiation is used to improve metabolism and stimulate blood circulation, disinfect food. With excessive heating, this radiation can greatly dry out the mucous membrane of the eye, and at maximum power even destroy the DNA molecule.

Radio waves are used for mobile and radio communications, navigation systems, television and other purposes. Constant exposure to radio frequencies emanating from household appliances can increase the excitability of the nervous system, impair brain function, and adversely affect the cardiovascular system and fertility.

Radioactive radiation is a powerful effect on the human body, capable of causing irreversible processes leading to tragic consequences. Depending on the power, various types of radioactive radiation can cause serious illnesses, or, on the contrary, can heal a person. Some of them are used for diagnostic purposes. In other words, everything depends on the controllability of the process, i.e. its intensity and duration of exposure to biological tissues.

The essence of the phenomenon

In general, the concept of radiation means the release of particles and their propagation in the form of waves. Radioactivity implies the spontaneous decay of the atomic nuclei of some substances with the appearance of a stream of high-power charged particles. Substances capable of such a phenomenon are called radionuclides.

So what is radioactive radiation? Usually, this term refers to both radioactive and radiation emissions. At its core, it is a directed flow of elementary particles of significant power that cause ionization of any medium that gets in their way: air, liquids, metals, minerals and other substances, as well as biological tissues. Ionization of any material leads to a change in its structure and basic properties. Biological tissues, incl. the human body undergo changes that are incompatible with their life.

Different types of radioactive radiation have different penetrating and ionizing properties. The damaging properties depend on the following main characteristics of radionucleides: type of radiation, flux power, half-life. The ionizing ability is assessed by a specific indicator: the number of ions of an ionized substance formed at a distance of 10 mm along the path of radiation penetration.

Negative impact on humans

Radiation exposure of a person leads to structural changes in the tissues of the body. As a result of ionization, free radicals appear in them, which are chemically active molecules that damage and kill cells. The first and most severely affected are the gastrointestinal, genitourinary and hematopoietic systems. There are pronounced symptoms of their dysfunction: nausea and vomiting, fever, stool disorder.

Radiation cataract caused by exposure of the eye tissues to radiation is quite typical. Other serious consequences of radiation exposure are observed: vascular sclerosis, a sharp decrease in immunity, hematogenous problems. Damage to the genetic mechanism is especially dangerous. The emerging active radicals are able to change the structure of the main carrier of genetic information - DNA. Such violations can lead to unpredictable mutations that affect the next generations.

The degree of damage to the human body depends on what types of radioactive radiation have occurred, what is the intensity and individual susceptibility of the body. The main indicator is the radiation dose, which shows how much radiation has penetrated into the body. It was found that a single large dose is much more dangerous than the accumulation of such a dose during prolonged exposure to low-power radiation. The amount of radiation absorbed by the body is measured in euvert (Ev).

Any living environment has a certain level of radiation. The radiation background is considered normal not higher than 0.18-0.2 mEv / h or 20 microroentgens. The critical level leading to death is estimated at 5.5-6.5 Ev.

Types of radiation

As noted, radioactive radiation and its types can affect the human body in different ways. The following main types of radiation can be distinguished.

Radiation of corpuscular type, which is a stream of particles:

1. Alpha radiation. This is a stream composed of alpha particles, which have a huge ionizing capacity, but the depth of penetration is small. Even a piece of thick paper can stop such particles. A person's clothing effectively plays the role of protection.
2. Beta radiation is caused by a stream of beta particles traveling at a speed close to the speed of light. Due to their tremendous speed, these particles have an increased penetrating ability, but their ionizing capabilities are lower than in the previous version. Window windows or a metal sheet with a thickness of 8-10 mm can serve as a screen from this radiation. It is very dangerous for humans if it comes into direct contact with the skin.
3. Neutron radiation consists of neutrons and has the greatest damaging effect. Sufficient protection against them is provided by materials in the structure of which there is hydrogen: water, paraffin, polyethylene, etc.

Wave radiation, which is a ray propagation of energy:

1. Gamma radiation is, in essence, an electromagnetic field created by radioactive transformations in atoms. Waves are emitted in the form of quanta, impulses. Radiation has a very high permeability, but low ionizing power. Heavy metal screens are needed to protect against such rays.
2. X-rays, or X-rays. These quantum rays are in many ways analogous to gamma rays, but the penetrating capabilities are somewhat underestimated. This type of wave is generated in vacuum X-ray installations due to the impact of electrons on a special target. The diagnostic purpose of this radiation is well known. However, it should be remembered that its prolonged action can cause serious harm to the human body.

How can a person be irradiated?

A person receives radioactive exposure if radiation penetrates into his body. It can happen in 2 ways: external and internal impact. In the first case, the source of radioactive radiation is outside, and a person, for various reasons, enters the field of his activity without proper protection. Internal exposure is carried out when a radionuclide penetrates into the body. This can happen when consuming irradiated foods or liquids, dust and gases, breathing contaminated air, etc.

External sources of radiation can be classified into 3 categories:

1. Natural sources: heavy chemical elements and radioactive isotopes.
2. Artificial sources: technical devices that provide radiation during appropriate nuclear reactions.
3. Induced radiation: various media, after being exposed to intense ionizing radiation, themselves become a source of radiation.

The most dangerous objects in terms of possible radiation exposure include the following radiation sources:

1. Production related to the extraction, processing, enrichment of radionuclides, the manufacture of nuclear fuel for reactors, in particular the uranium industry.
2. Nuclear reactors of any type, incl. at power plants and ships.
3. Radiochemical enterprises engaged in the regeneration of nuclear fuel.
4. Storage (burial) sites for radioactive waste, as well as enterprises for their processing.
5. When using radiation in various industries: medicine, geology, agriculture, industry, etc.
6. Trial nuclear weapons, nuclear explosions for peaceful purposes.

Manifestation of damage to the body

The characteristic of radioactive radiation plays a decisive role in the degree of damage to the human body. As a result of exposure, radiation sickness develops, which can have 2 directions: somatic and genetic damage. By the time of manifestation, an early and long-term effect stands out.

An early effect reveals characteristic symptoms in the period from 1 hour to 2 months. The following signs are considered typical: skin redness and peeling, turbidity of the eye lens, a violation of the hematopoietic process. An extreme option with a high dose of radiation is a lethal outcome. Local lesions are characterized by such signs as radiation burns of the skin and mucous membranes.

Distant manifestations come to light after 3-5 months, or even after several years. In this case, there are persistent skin lesions, malignant tumors of various localization, a sharp deterioration in immunity, a change in blood composition (a significant decrease in the level of erythrocytes, leukocytes, platelets and neutrophils). As a result, various infectious diseases often develop, and life expectancy is significantly reduced.

To prevent exposure of a person to ionizing radiation, various types of protection are used, which depend on the type of radiation. In addition, strict standards are regulated for the maximum duration of a person's stay in the irradiated area, the minimum distance to the radiation source, the use of personal protective equipment and the installation of protective screens.

Radioactive radiation can have a strong destructive effect on all tissues of the human body. At the same time, it is also used in the treatment of various diseases. It all depends on the dose of radiation received by a person in a single or long-term mode. Only strict observance of radiation protection standards will help maintain health, even if you are within the range of a radiation source.

Navigation through the article:

Radiation and types of radioactive radiation, the composition of radioactive (ionizing) radiation and its main characteristics. The effect of radiation on matter.

What is radiation

First, let's give a definition of what radiation is:

In the process of disintegration of a substance or its synthesis, the ejection of atomic elements (protons, neutrons, electrons, photons) occurs, otherwise we can say radiation occurs these elements. Such radiation is called - ionizing radiation or what is more common radioactive radiation, or even simpler radiation ... Ionizing radiation also includes X-ray and gamma radiation.

Radiation is the process of radiation by matter of charged elementary particles, in the form of electrons, protons, neutrons, helium atoms or photons and muons. The type of radiation depends on which element is emitted.

Ionization is the process of formation of positively or negatively charged ions or free electrons from neutrally charged atoms or molecules.

Radioactive (ionizing) radiation can be divided into several types, depending on the type of elements from which it consists. Different types Radiation is caused by various microparticles and therefore has a different energy effect on a substance, a different ability to penetrate through it and, as a consequence, a different biological effect of radiation.

Alpha, beta and neutron radiation are radiation consisting of various particles of atoms.

Gamma and X-ray is the radiation of energy.

Alpha radiation

• emitted: two protons and two neutrons
• penetrating ability: low
• irradiation from the source: up to 10 cm
• emission rate: 20,000 km / s
• ionization: 30,000 pairs of ions per 1 cm of run
• high

Alpha (α) radiation arises from the decay of unstable isotopes elements.

Alpha radiation- this is the radiation of heavy, positively charged alpha particles, which are the nuclei of helium atoms (two neutrons and two protons). Alpha particles are emitted during the decay of more complex nuclei, for example, during the decay of uranium, radium, thorium atoms.

Alpha particles have a large mass and are emitted at a relatively low speed, on average 20 thousand km / s, which is about 15 times less than the speed of light. Since alpha particles are very heavy, when in contact with a substance, the particles collide with the molecules of this substance, begin to interact with them, losing their energy, and therefore the penetrating ability of these particles is not great and even a simple sheet of paper can detain them.

However, alpha particles carry a lot of energy and, when interacting with a substance, cause its significant ionization. And in the cells of a living organism, in addition to ionization, alpha radiation destroys tissues, leading to various damage to living cells.

Of all types of radiation, alpha radiation has the lowest penetrating ability, but the consequences of irradiation of living tissues with this type of radiation are the most severe and significant in comparison with other types of radiation.

Exposure to radiation in the form of alpha radiation can occur when radioactive elements enter the body, for example, through air, water, or food, or through cuts or wounds. Once in the body, these radioactive elements are carried by the blood stream throughout the body, accumulate in tissues and organs, exerting a powerful energetic effect on them. Since some types of radioactive isotopes emitting alpha radiation have a long lifespan, getting inside the body, they can cause serious changes in cells and lead to tissue degeneration and mutations.

Radioactive isotopes are not actually excreted from the body on their own, therefore, getting inside the body, they will irradiate tissues from the inside for many years until they lead to serious changes. The human body is not able to neutralize, process, assimilate or utilize most of the radioactive isotopes that have entered the body.

Neutron radiation

• emitted: neutrons
• penetrating ability: high
• irradiation from the source: kilometers
• emission rate: 40,000 km / s
• ionization: from 3000 to 5000 pairs of ions per 1 cm of run
• biological effect of radiation: high

Neutron radiation- This is man-made radiation arising in various nuclear reactors and atomic explosions. Also, neutron radiation is emitted by stars in which active thermonuclear reactions take place.

Having no charge, neutron radiation, colliding with matter, weakly interacts with elements of atoms at the atomic level, therefore it has a high penetrating ability. It is possible to stop neutron radiation using materials with a high hydrogen content, for example, a container with water. Neutron radiation also poorly penetrates polyethylene.

Neutron radiation, when passing through biological tissues, causes serious damage to cells, since it has a significant mass and a higher speed than alpha radiation.

Beta radiation

• emitted: electrons or positrons
• penetrating ability: average
• irradiation from the source: up to 20 m
• emission rate: 300,000 km / s
• ionization: from 40 to 150 pairs of ions per 1 cm of run
• biological effect of radiation: the average

Beta (β) radiation occurs when one element transforms into another, while processes occur in the very nucleus of an atom of a substance with a change in the properties of protons and neutrons.

With beta radiation, there is a transformation of a neutron into a proton or a proton into a neutron, with this transformation there is an emission of an electron or a positron (antiparticle of an electron), depending on the type of transformation. The speed of the emitted elements approaches the speed of light and is approximately equal to 300,000 km / s. The elements emitted in this case are called beta particles.

Having initially a high radiation speed and small dimensions of the emitted elements, beta radiation has a higher penetrating power than alpha radiation, but has a hundreds of times less ability to ionize matter than alpha radiation.

Beta radiation easily penetrates through clothing and partially through living tissues, but when passing through denser structures of a substance, for example, through a metal, it begins to interact more intensively with it and loses most of its energy transferring it to the elements of the substance. A metal sheet of a few millimeters can completely stop beta radiation.

If alpha radiation is dangerous only in direct contact with a radioactive isotope, then beta radiation, depending on its intensity, can already cause significant harm to a living organism at a distance of several tens of meters from the radiation source.

If a radioactive isotope emitting beta radiation enters a living organism, it accumulates in tissues and organs, exerting an energetic effect on them, leading to changes in the structure of tissues and causing significant damage over time.

Some radioactive isotopes with beta radiation have a long decay period, that is, once they enter the body, they will irradiate it for years until they lead to tissue degeneration and, as a result, to cancer.

Gamma radiation

• emitted: energy in the form of photons
• penetrating ability: high
• irradiation from the source: up to hundreds of meters
• emission rate: 300,000 km / s
• ionization:
• biological effect of radiation: low

Gamma (γ) radiation is energetic electromagnetic radiation in the form of photons.

Gamma radiation accompanies the process of decay of atoms of a substance and manifests itself in the form of radiated electromagnetic energy in the form of photons released when the energy state of the atomic nucleus changes. Gamma rays are emitted from the nucleus at the speed of light.

When the radioactive decay of an atom occurs, others are formed from some substances. The atom of newly formed substances is in an energetically unstable (excited) state. Acting on each other, neutrons and protons in the nucleus come to a state where the forces of interaction are balanced, and the excess energy is emitted by the atom in the form of gamma radiation

Gamma radiation has a high penetrating ability and easily penetrates through clothes, living tissues, a little more difficult through dense structures of a substance such as metal. To stop gamma rays, a significant thickness of steel or concrete is required. But at the same time, gamma radiation has a hundred times weaker effect on matter than beta radiation and tens of thousands of times weaker than alpha radiation.

The main danger of gamma radiation is its ability to travel long distances and affect living organisms several hundred meters from the source of gamma radiation.

X-ray radiation

• emitted: energy in the form of photons
• penetrating ability: high
• irradiation from the source: up to hundreds of meters
• emission rate: 300,000 km / s
• ionization: from 3 to 5 pairs of ions per 1 cm of run
• biological effect of radiation: low

X-ray radiation- This is energetic electromagnetic radiation in the form of photons arising from the transition of an electron inside an atom from one orbit to another.

X-ray radiation is similar in action to gamma radiation, but is less penetrating because it has a longer wavelength.

Having considered various types of radioactive radiation, it is clear that the concept of radiation includes completely different types of radiation that have different effects on matter and living tissues, from direct bombardment with elementary particles (alpha, beta and neutron radiation) to energy effects in the form of gamma and X-rays. healing.

Each of the considered emissions is dangerous!

Comparative table with characteristics of different types of radiation

characteristic	Type of radiation
	Alpha radiation	Neutron radiation	Beta radiation	Gamma radiation	X-ray radiation
emitted	two protons and two neutrons	neutrons	electrons or positrons	energy in the form of photons	energy in the form of photons
penetrating power	low	high	average	high	high
source irradiation	up to 10 cm	kilometers	up to 20 m	hundreds of meters	hundreds of meters
emission rate	20,000 km / s	40,000 km / s	300,000 km / s	300,000 km / s	300,000 km / s
ionization, steam per 1 cm of run	30 000	from 3000 to 5000	from 40 to 150	from 3 to 5	from 3 to 5
biological effects of radiation	high	high	the average	low	low

As can be seen from the table, depending on the type of radiation, radiation at the same intensity, for example, 0.1 Roentgen, will have a different destructive effect on the cells of a living organism. To take into account this difference, the coefficient k was introduced, reflecting the degree of exposure to radioactive radiation on living objects.

Coefficient k
Type of radiation and energy range	Weight factor
Photons all energies (gamma radiation)	1
Electrons and muons all energies (beta radiation)	1
Neutrons with energy < 10 КэВ (нейтронное излучение)	5
Neutrons from 10 to 100 keV (neutron radiation)	10
Neutrons from 100 keV to 2 MeV (neutron radiation)	20
Neutrons from 2 MeV to 20 MeV (neutron radiation)	10
Neutrons> 20 MeV (neutron radiation)	5
Protons with energies> 2 MeV (except for recoil protons)	5
Alpha particles, fission fragments and other heavy nuclei (alpha radiation)	20

The higher the "k coefficient", the more dangerous the action a certain kind radiation for the tissues of a living organism.

Video:

Task (to warm up):

I'll tell you, my friends,
How to grow mushrooms:
Need to go to the field early in the morning
Move two pieces of uranium ...

Question: What is the total mass of pieces of uranium for a nuclear explosion to occur?

Answer(in order to see the answer - you need to select the text) : For uranium-235, the critical mass is about 500 kg. If we take a ball of such a mass, then the diameter of such a ball will be 17 cm.

Radiation, what is it?

Radiation (translated from English "radiation") is radiation that is applied not only to radioactivity, but also to a number of other physical phenomena, for example: solar radiation, thermal radiation, etc. (International Commission on Radiation Protection) and radiation safety rules, the phrase "ionizing radiation".

What is ionizing radiation?

Ionizing radiation - radiation (electromagnetic, corpuscular), which causes ionization (the formation of ions of both signs) of a substance (environment). The probability and number of ion pairs formed depends on the energy of the ionizing radiation.

Radioactivity, what is it?

Radioactivity - radiation from excited nuclei or spontaneous transformation of unstable atomic nuclei into nuclei of other elements, accompanied by the emission of particles or γ-quantum (s). The transformation of ordinary neutral atoms into an excited state occurs under the influence of external energies of various kinds. Further, the excited nucleus seeks to remove excess energy by radiation (emission of an alpha particle, electrons, protons, gamma quanta (photons), neutrons), until a stable state is reached. Many heavy nuclei (transuranium series in the periodic table - thorium, uranium, neptunium, plutonium, etc.) are initially in an unstable state. They are able to spontaneously disintegrate. This process is also accompanied by radiation. Such nuclei are called natural radionuclides.

This animation clearly shows the phenomenon of radioactivity.

The Wilson chamber (plastic box cooled to -30 ° C) is filled with isopropyl alcohol vapor. Julien Simon placed a 0.3-cm³ piece of radioactive uranium (uraninite mineral) in it. The mineral emits alpha particles and beta particles, as it contains U-235 and U-238. On the path of movement of α and beta particles are molecules of isopropyl alcohol.

Since the particles are charged (alpha - positive, beta - negative), they can take an electron from the alcohol molecule (alpha particle) or add electrons to the alcohol molecules of the beta particle). This, in turn, gives the molecules a charge, which then attracts uncharged molecules around them. When the molecules clump together, they produce noticeable white clouds, which is clearly visible in the animation. So we can easily trace the paths of the ejected particles.

α particles create straight, dense clouds, while beta particles create long ones.

Isotopes, what are they?

Isotopes are a variety of atoms of the same chemical element, having different mass numbers, but including the same electric charge of atomic nuclei and, therefore, occupying D.I. Mendeleev single place. For example: 131 55 Cs, 134 m 55 Cs, 134 55 Cs, 135 55 Cs, 136 55 Cs, 137 55 Cs. Those. charge largely determines Chemical properties element.

There are isotopes stable (stable) and unstable (radioactive isotopes) - spontaneously decaying. About 250 stable and about 50 natural radioactive isotopes are known. An example of a stable isotope is 206 Pb, which is the end product of the decay of the natural radionuclide 238 U, which in turn appeared on our Earth at the beginning of mantle formation and is not associated with technogenic pollution.

What types of ionizing radiation are there?

The main types of ionizing radiation that are most often encountered are:

• alpha radiation;
• beta radiation;
• gamma radiation;
• X-ray radiation.

Of course, there are other types of radiation (neutron, positron, etc.), but we meet with them in everyday life much less often. Each type of radiation has its own nuclear-physical characteristics and, as a consequence, different biological effects on the human body. Radioactive decay can be accompanied by one of the types of radiation or several at once.

Sources of radioactivity can be natural or artificial. Natural sources of ionizing radiation are radioactive elements found in the earth's crust and forming a natural background radiation along with cosmic radiation.

Artificial sources of radioactivity are usually formed in nuclear reactors or accelerators based on nuclear reactions. Sources of artificial ionizing radiation can also be a variety of electrical vacuum physical devices, charged particle accelerators, etc. For example: a TV picture tube, an X-ray tube, a kenotron, etc.

Alpha radiation (α radiation) - corpuscular ionizing radiation, consisting of alpha particles (helium nuclei). Formed during radioactive decay and nuclear transformations. Helium nuclei have a fairly large mass and energy up to 10 MeV (Megaelectron-Volt). 1 eV = 1.6 ∙ 10 -19 J. Having an insignificant range in the air (up to 50 cm), they pose a high danger to biological tissues if they contact the skin, mucous membranes of the eyes and respiratory tract, if they enter the body in the form of dust or gas ( radon-220 and 222). The toxicity of alpha radiation is due to the colossal high ionization density due to its high energy and mass.

Beta radiation (β-radiation) - corpuscular electron or positron ionizing radiation of the corresponding sign with a continuous energy spectrum. It is characterized by the maximum energy of the spectrum E β max, or the average energy of the spectrum. The range of electrons (beta particles) in the air reaches several meters (depending on the energy), in biological tissues the range of a beta particle is several centimeters. Beta radiation, like alpha radiation, is a hazard due to contact radiation (surface contamination), for example, if it gets inside the body, on mucous membranes and skin.

Gamma radiation (γ-radiation or gamma quanta) - short-wave electromagnetic (photon) radiation with a wavelength

X-rays - by their own physical properties similar to gamma radiation, but with a number of features. It appears in the X-ray tube due to the abrupt stop of electrons on the ceramic target-anode (the place where the electrons strike is made, as a rule, of copper or molybdenum) after acceleration in the tube (continuous spectrum - bremsstrahlung) and when electrons are knocked out of the internal electronic shells of the target atom (line spectrum). The energy of X-ray radiation is low - from fractions of a few eV to 250 keV. X-rays can be obtained using charged particle accelerators - synchrotron radiation with a continuous spectrum having an upper limit.

Passage of radiation and ionizing radiation through obstacles:

The sensitivity of the human body to the effects of radiation and ionizing radiation on it:

What is a radiation source?

Ionizing radiation source (IRS) - an object that includes a radioactive substance or technical device that creates or, in certain cases, is capable of creating ionizing radiation. Distinguish between closed and open sources of radiation.

What are radionuclides?

Radionuclides are nuclei subject to spontaneous radioactive decay.

What is half-life?

Half-life is the period of time during which the number of nuclei of a given radionuclide as a result of radioactive decay is halved. This value is used in the law of radioactive decay.

In what units is radioactivity measured?

The activity of a radionuclide in accordance with the SI measurement system is measured in Becquerel (Bq) - named after the French physicist who discovered radioactivity in 1896), Henri Becquerel. One Bq is equal to 1 nuclear transformation per second. The power of the radioactive source is measured in Bq / s, respectively. The ratio of the activity of a radionuclide in a sample to the mass of a sample is called the specific activity of a radionuclide and is measured in Bq / kg (l).

In what units is ionizing radiation measured (X-ray and gamma)?

What do we see on the display of modern dosimeters that measure AI? The ICRP proposed to measure the dose at a depth d equal to 10 mm to assess human exposure. The measured value of the dose at this depth is called the ambient dose equivalent, measured in sieverts (Sv). In fact, this is a calculated value, where the absorbed dose is multiplied by a weighting factor for a given type of radiation and a factor characterizing the sensitivity of various organs and tissues to a particular type of radiation.

The equivalent dose (or the often used term “dose”) is equal to the product of the absorbed dose and the quality factor of exposure to ionizing radiation (for example: the quality factor of exposure to gamma radiation is 1, and alpha radiation is 20).

The unit of measure for the equivalent dose is rem (biological equivalent of an X-ray) and its sub-multiples: millirem (mrem) microrem (microrem), etc., 1 rem = 0.01 J / kg. The unit of measurement of the equivalent dose in the SI system is sievert, Sv,

1 Sv = 1 J / kg = 100 rem.

1 mrem = 1 * 10 -3 rem; 1 μrem = 1 * 10 -6 rem;

Absorbed dose - the amount of energy of ionizing radiation that is absorbed in an elementary volume, referred to the mass of matter in this volume.

The unit of the absorbed dose is rad, 1 rad = 0.01 J / kg.

The SI unit of absorbed dose is gray, Gy, 1 Gy = 100 rad = 1 J / kg

The equivalent dose rate (or dose rate) is the ratio of the equivalent dose to the time interval of its measurement (exposure), unit of measure rem / hour, Sv / hour, μSv / s, etc.

What units are alpha and beta radiation measured in?

The amount of alpha and beta radiation is defined as the flux density of particles per unit area, per unit time - a-particles * min / cm 2, β-particles * min / cm 2.

What is radioactive around us?

Almost everything that surrounds us, even the person himself. Natural radioactivity is to some extent a natural human habitat, if it does not exceed natural levels. There are areas on the planet with an increased relative to the average level of the radiation background. However, in most cases, no significant deviations in the health status of the population are observed, since this territory is their natural habitat. An example of such a piece of land is, for example, the state of Kerala in India.

For a true assessment of the frightening figures that sometimes appear in print, one should distinguish:

• natural, natural radioactivity;
• technogenic, i.e. changes in the radioactivity of the environment under the influence of man (mining, emissions and discharges of industrial enterprises, emergencies and much more).

As a rule, it is almost impossible to eliminate elements of natural radioactivity. How can you get rid of 40 K, 226 Ra, 232 Th, 238 U, which are everywhere in the earth's crust and are found in almost everything that surrounds us, and even in ourselves?

Of all natural radionuclides, the decay products of natural uranium (U-238) - radium (Ra-226) and radioactive gas radon (Ra-222) - pose the greatest danger to human health. The main "suppliers" of radium-226 to the environment are enterprises engaged in the extraction and processing of various fossil materials: mining and processing of uranium ores; oil and gas; coal industry; production building materials; energy industry enterprises, etc.

Radium-226 is highly susceptible to leaching from uranium containing minerals. This property explains the presence of large amounts of radium in some types of groundwater (some of them enriched with radon gas are used in medical practice), in mine waters. The range of radium content in groundwater varies from a few to tens of thousands of Bq / L. The radium content in natural surface waters is much lower and can range from 0.001 to 1–2 Bq / L.

A significant component of natural radioactivity is the decay product of radium-226 - radon-222.

Radon is an inert, radioactive gas, colorless and odorless with a half-life of 3.82 days. Alpha emitter. It is 7.5 times heavier than air, therefore it mostly concentrates in cellars, basements, basements of buildings, in mine workings, etc.

It is believed that up to 70% of the exposure of the population to radiation is associated with radon in residential buildings.

The main source of radon intake in residential buildings are (as the importance increases):

• tap water and gas;
• building materials (crushed stone, granite, marble, clay, slags, etc.);
• soil under buildings.

In more detail about radon and a device for measuring it: RADON AND TORON RADIOMETERS.

Professional radon radiometers cost unaffordable money, for household use - we recommend that you pay attention to a household radon and thoron radiometer made in Germany: Radon Scout Home.

What are "black sands" and how dangerous are they?

"Black sands" (the color varies from light yellow to red-brown, brown, there are varieties of white, greenish tint and black) are the mineral monazite - anhydrous phosphate of the elements of the thorium group, mainly cerium and lanthanum (Ce, La) PO 4 which are replaced by thorium. Monazite contains up to 50-60% of oxides of rare-earth elements: yttrium oxide Y 2 O 3 up to 5%, thorium oxide ThO 2 up to 5-10%, sometimes up to 28%. Occurs in pegmatites, sometimes in granites and gneisses. When rocks containing monazite are destroyed, it is collected in placers, which are large deposits.

Placers of monazite sands existing on land, as a rule, do not significantly change the resulting radiation environment. But the deposits of monazite located near the coastal strip of the Sea of ​​Azov (within the Donetsk region), in the Urals (Krasnoufimsk) and other regions create a number of problems associated with the possibility of irradiation.

For example, because of the sea surf during the autumn-spring period on the coast, as a result of natural flotation, a significant amount of "black sand" is accumulated, characterized by a high content of thorium-232 (up to 15-20 thousand Bq / kg and more), which creates in local areas, the levels of gamma radiation are of the order of 3.0 and more μSv / hour. Naturally, it is unsafe to rest in such areas, so this sand is collected every year, warning signs are displayed, and some parts of the coast are closed.

Means for measuring radiation and radioactivity.

To measure the radiation levels and the content of radionuclides in different objects, special measuring instruments are used:

• to measure the exposure dose rate of gamma radiation, X-ray radiation, flux density of alpha and beta radiation, neutrons, dosimeters and search dosimeters-radiometers of various types are used;
• to determine the type of radionuclide and its content in environmental objects, II spectrometers are used, which consist of a radiation detector, an analyzer and personal computer with the corresponding program for processing the radiation spectrum.

Currently, there are a large number of dosimeters of various types for solving various problems of radiation monitoring and having wide capabilities.

For example, dosimeters that are most often used in professional activities:

1. Dosimeter-radiometer MKS-AT1117M(search dosimeter-radiometer) - a professional radiometer is used to search for and identify sources of photon radiation. It has a digital indicator, the ability to set the threshold for the sound signaling device, which greatly facilitates the work when examining territories, checking scrap metal, etc. Remote detection unit. A NaI scintillation crystal is used as a detector. The dosimeter is a versatile solution to various tasks; it is completed with a dozen different detecting units with different technical characteristics. Measuring units allow you to measure alpha, beta, gamma, X-ray and neutron radiation.

   Information about detecting units and their application:

Detection unit name	Measured radiation	Main feature (technical specification)	Application area
	OBD for alpha radiation	Measurement range 3.4 · 10 -3 - 3.4 · 10 3 Bq · cm -2	DB for measuring the flux density of alpha particles from the surface
	OBD for beta radiation	Measurement range 1 - 5 · 10 5 part./ (min · cm 2)	DB for measuring the flux density of beta particles from the surface
	OBD for gamma radiation	Sensitivity 350 cps -1 / μSvh -1 measurement range 0.03 - 300 μSv / h	The best option for price, quality, specifications. It is widely used in the field of gamma radiation measurement. A good search detector for finding radiation sources.
	OBD for gamma radiation	Measurement range 0.05 μSv / h - 10 Sv / h	A detector unit with a very high upper threshold for measuring gamma radiation.
	OBD for gamma radiation	Measurement range 1 mSv / h - 100 Sv / h Sensitivity 900 cps -1 / μSvh -1	An expensive detector with a high measuring range and excellent sensitivity. Used to locate radiation sources with strong radiation.
	X-ray OBD	Energy range 5 - 160 keV	X-ray detection unit. It is widely used in medicine and installations working with the release of low-energy X-rays.
	DB for neutron radiation	measurement range 0.1 - 10 4 neutrons / (s cm 2) Sensitivity 1.5 (cps -1) / (neutron s -1 cm -2)
	OBD for alpha, beta, gamma and X-ray radiation	Sensitivity 6.6 cps -1 / μSv h -1	A universal detector unit that allows you to measure alpha, beta, gamma and X-ray radiation. Low cost and poor sensitivity. I found wide reconciliation in the field of attestation of workplaces (AWP), where it is mainly required to measure a local object.

2. Dosimeter-radiometer DKS-96- designed to measure gamma and X-ray radiation, alpha radiation, beta radiation, neutron radiation.

In many ways it is similar to a dosimeter-radiometer.

• measurement of dose and rate of ambient dose equivalent (hereinafter dose and dose rate) Н * (10) and Н * (10) of continuous and pulsed X-ray and gamma radiation;
• measurement of the flux density of alpha and beta radiation;
• measurement of the dose H * (10) of neutron radiation and the dose rate H * (10) of neutron radiation;
• measurement of the flux density of gamma radiation;
• search, as well as localization of radioactive sources and sources of pollution;
• measurement of flux density and exposure dose rate of gamma radiation in liquid media;
• radiation analysis of the terrain, taking into account geographic coordinates, using GPS;

The two-channel scintillation beta-gamma spectrometer is designed for simultaneous and separate determination of:

• specific activity of 137 Cs, 40 K and 90 Sr in samples from various environments;
• specific effective activity of natural radionuclides 40 K, 226 Ra, 232 Th in building materials.

Allows to provide express analysis of standardized samples of metal heats for the presence of radiation and contamination.

9. HPGe detector based gamma spectrometer Spectrometers based on coaxial detectors made of HPGe (highly pure germanium) are designed to register gamma radiation in the energy range from 40 keV to 3 MeV.

MKS-AT1315 beta and gamma radiation spectrometer



NaI PAK Lead Shielded Spectrometer



Portable NaI spectrometer MKS-AT6101





Wearable HPGe spectrometer Eco PAK



Portable HPGe spectrometer Eco PAK



Automotive NaI PAK spectrometer



Spectrometer MKS-AT6102



Eco PAK spectrometer with electromachine cooling



Handheld PPD spectrometer Eco PAK

Explore other measuring instruments to measure ionizing radiation, you can on our website:

• when carrying out dosimetric measurements, if they are meant to be carried out frequently in order to monitor the radiation situation, it is necessary to strictly observe the geometry and measurement technique;
• to increase the reliability of dosimetric control, it is necessary to carry out several measurements (but not less than 3), then calculate the arithmetic mean;
• when measuring the background of the dosimeter on the ground, select areas that are 40 m away from buildings and structures;
• measurements on the ground are carried out at two levels: at a height of 0.1 (search) and 1.0 m (measurement for the protocol - in this case, the sensor should be rotated in order to determine the maximum value on the display) from the ground surface;
• when measuring in residential and public premises, measurements are taken at a height of 1.0 m from the floor, preferably at five points by the "envelope" method. At first glance, it is difficult to understand what is happening in the photograph. A giant mushroom seemed to grow from under the floor, and ghostly people in helmets seemed to be working next to it ...

  At first glance, it is difficult to understand what is happening in the photograph. A giant mushroom seemed to grow from under the floor, and ghostly people in helmets seemed to be working next to it ...

  There is something inexplicably creepy about this scene, and for a reason. This is the largest accumulation of possibly the most toxic substance ever created by man. This is nuclear lava or corium.

  In the days and weeks after the Chernobyl nuclear power plant disaster on April 26, 1986, simply walking into a room with the same pile of radioactive material - she was somberly nicknamed "elephant's leg" - meant certain death in a few minutes. Even a decade later, when this photograph was taken, the film was probably behaving strangely due to radiation, which manifested itself in a characteristic grain structure. The person in the photo, Artur Korneev, most likely visited this room more often than anyone else, so he was exposed, perhaps, to the maximum dose of radiation.

  Surprisingly, in all likelihood, he is still alive. The story of how the United States took possession of a unique photograph of a person in the presence of incredibly toxic material is shrouded in mystery in itself - as well as the reasons why someone would need to take a selfie next to a hump of molten radioactive lava.

  The photograph first came to America in the late 90s, when the new government of newly independent Ukraine took control of the Chernobyl nuclear power plant and opened the Chernobyl Center for Nuclear Safety, Radioactive Waste and Radioecology. Soon, the Chernobyl Center invited other countries to cooperate in nuclear safety projects. The US Department of Energy has ordered assistance by sending an order to Pacific Northwest National Laboratories (PNNL), a crowded research facility in Richland, PA. Washington.

  At the time, Tim Ledbetter was one of the newcomers to PNNL's IT department, and was tasked with creating a digital photo library for the DOE Nuclear Security Project, that is, to show the photographs to the American public (more precisely, for that tiny part of the public, which then had access to the Internet). He asked the project participants to take photographs during their trips to Ukraine, hired a freelance photographer, and also asked for materials from Ukrainian colleagues at the Chernobyl Center. Among hundreds of photographs of clumsy handshakes of officials and people in lab coats, however, there are a dozen photographs of the ruins inside the fourth power unit, where a decade earlier, on April 26, 1986, an explosion occurred during a test of a turbine generator.

  As radioactive smoke rose above the village, poisoning the surrounding land, rods liquefied from below, melting through the walls of the reactor and forming a substance called corium.

  When radioactive smoke rose above the village, poisoning the surrounding land, rods liquefied from below, melting through the walls of the reactor and forming a substance called corium .

  Corium has formed outside research laboratories at least five times, says Mitchell Farmer, a lead nuclear engineer at Argonne National Laboratory, another US Department of Energy facility near Chicago. A corium once formed at the Three Mile Island reactor in Pennsylvania in 1979, once in Chernobyl, and three times during the meltdown of the Fukushima reactor in 2011. In his laboratory, Farmer created modified versions of the corium to better understand how to avoid similar incidents in the future. The study of the substance showed, in particular, that watering with water after the formation of the corium in reality prevents the decay of some elements and the formation of more dangerous isotopes.

  Of the five cases of corium formation, only in Chernobyl nuclear lava was able to escape from the reactor. Without a cooling system, the radioactive mass crawled through the power unit for a week after the accident, absorbing molten concrete and sand, which were mixed with molecules of uranium (fuel) and zirconium (coating). This poisonous lava flowed downward, eventually melting the floor of the building. When inspectors finally entered the power unit a few months after the accident, they found an 11-ton, three-meter-long landslide in the corner of the steam distribution corridor below. Then it was called "elephant's leg". Over the next years, the "elephant leg" was cooled and crushed. But even today, its remnants are still several degrees warmer than the environment, as the decay of radioactive elements continues.

  Ledbetter cannot remember exactly where he obtained these photographs. He put together a photo library nearly 20 years ago, and the website where they are hosted is still in good shape; only small copies of images were lost. (Ledbetter, still at PNNL, was surprised to learn that the photos are still available online.) But he remembers for sure that he did not send anyone to photograph the "elephant's leg", so it was most likely sent by one of his Ukrainian colleagues.

  The photo began to circulate on other sites, and in 2013 Kyle Hill came across it when he was writing an article about the "elephant's leg" for Nautilus magazine. He traced her origins back to the PNNL lab. A long-lost description of the photo was found on the site: "Artur Korneev, deputy director of the Shelter, is studying nuclear lava" elephant's leg ", Chernobyl. Photographer: unknown. Autumn 1996". Ledbetter confirmed that the description matched the photograph.

  Arthur Korneev- an inspector from Kazakhstan, who was engaged in the education of employees, telling and protecting them from the "elephant's leg" since its formation after the explosion at the Chernobyl nuclear power plant in 1986, a gloomy joke lover. Most likely, the last to speak to him was the NY Times reporter in 2014 in Slavutich, a city specially built for evacuated personnel from Pripyat (Chernobyl).

  The photo was probably taken with a slower shutter speed than other photos to allow the photographer to appear in the frame, which explains the effect of movement and why the headlamp looks like lightning. The graininess in the photo is probably caused by radiation.

  For Korneev, this particular visit to the power unit was one of several hundred dangerous trips to the core since his first day of operation in the days following the explosion. His first assignment was to detect fuel deposits and help measure radiation levels (the "elephant's leg" initially "glowed" at more than 10,000 roentgens per hour, which kills a person at a distance of a meter in less than two minutes). Shortly thereafter, he led a clean-up operation, when whole chunks of nuclear fuel sometimes had to be removed from the path. More than 30 people died from acute radiation sickness during the cleaning of the power unit. Despite the incredible dose of radiation received, Korneev himself continued to return to the hastily constructed concrete sarcophagus again and again, often with journalists to shield them from danger.

  In 2001, he took an Associated Press reporter to the core, where radiation levels were 800 roentgens per hour. In 2009, renowned fictional writer Marcel Theroux wrote an article for Travel + Leisure about his trip to the sarcophagus and about a crazy escort without a gas mask who mocked Teru’s fears and said it was "pure psychology." Although Theroux referred to him as Viktor Korneev, Arthur was in all likelihood the person, since he dropped the same black jokes a few years later with a journalist from the NY Times.

  His current occupation is unknown. When the Times found Korneev a year and a half ago, he was helping build the vault for the sarcophagus, a $ 1.5 billion project due to be completed in 2017. It is planned that the vault will completely close the Vault and prevent isotope leakage. In his 60-something years, Korneev looked sickly, suffered from cataracts, and was banned from visiting the sarcophagus after repeated exposure in previous decades.

  However, Korneev's sense of humor remained unchanged... He seems to have no regrets about his life's work: "Soviet radiation," he jokes, "is the best radiation in the world." .

  
  

Radioactive (or ionizing) radiation is energy that is released by atoms in the form of particles or waves of an electromagnetic nature. A person is exposed to such an impact both through natural and through anthropogenic sources.

The beneficial properties of radiation made it possible to successfully use it in industry, medicine, scientific experiments and research, agriculture and other fields. However, with the spread of the use of this phenomenon, a threat to human health has arisen. A small dose of radioactive radiation can increase the risk of acquiring serious diseases.

The difference between radiation and radioactivity

Radiation, in a broad sense, means radiation, that is, the propagation of energy in the form of waves or particles. Radioactive radiation is divided into three types:

• alpha radiation - flux of helium-4 nuclei;
• beta radiation - electron flow;
• gamma radiation - a stream of high-energy photons.

The characterization of radioactive emissions is based on their energy, transmission properties and the type of emitted particles.

Alpha radiation, which is a flux of positively charged particles, can be trapped by air or clothing. This species practically does not penetrate the skin, but when it enters the body, for example, through cuts, it is very dangerous and has a detrimental effect on internal organs.

Beta radiation has more energy - electrons move at high speed, and their size is small. Therefore, this type of radiation penetrates through thin clothing and skin deep into the tissues. Beta radiation can be shielded with a few millimeters of aluminum or a thick wooden board.

Gamma radiation is a high-energy radiation of an electromagnetic nature that has a strong penetrating power. To protect against it, you need to use a thick layer of concrete or a plate of heavy metals such as platinum and lead.

The phenomenon of radioactivity was discovered in 1896. The discovery was made by the French physicist Becquerel. Radioactivity is the ability of objects, compounds, elements to emit ionizing study, that is, radiation. The reason for the phenomenon lies in the instability of the atomic nucleus, which releases energy during decay. There are three types of radioactivity:

• natural - typical for heavy elements, the ordinal number of which is more than 82;
• artificial - initiated specifically by nuclear reactions;
• directed - characteristic of objects that themselves become a source of radiation if they are strongly irradiated.

Elements with radioactivity are called radionuclides. Each of them is characterized by:

• half-life;
• the type of radiation emitted;
• radiation energy;
• and other properties.

Sources of radiation

The human body is regularly exposed to radioactive radiation. Cosmic rays account for approximately 80% of the amount received annually. Air, water and soil contain 60 radioactive elements that are sources of natural radiation. The main natural source of radiation is considered to be the inert gas radon, which is released from the ground and rocks. Radionuclides also enter the human body with food. Some of the ionizing radiation that humans are exposed to comes from anthropogenic sources, ranging from nuclear power generators and nuclear reactors to radiation used for treatment and diagnosis. Today, common artificial radiation sources are:

• medical equipment (the main anthropogenic source of radiation);
• radiochemical industry (mining, enrichment of nuclear fuel, processing of nuclear waste and their recovery);
• radionuclides used in agriculture, light industry;
• accidents at radiochemical plants, nuclear explosions, radiation releases
• Construction Materials.

Radiation exposure, according to the method of penetration into the body, is divided into two types: internal and external. The latter is typical for radionuclides (aerosol, dust) sprayed into the air. They come into contact with skin or clothing. In this case, the sources of radiation can be removed by rinsing them off. External radiation causes burns to the mucous membranes and skin. In the internal type, the radionuclide enters the bloodstream, for example, by injection into a vein or through wounds, and is removed by excretion or therapy. Such radiation provokes malignant tumors.

The radioactive background significantly depends on the geographic location - in some regions, the radiation level can be hundreds of times higher than the average.

The effect of radiation on human health

Due to its ionizing effect, radioactive radiation leads to the formation of free radicals in the human body - chemically active aggressive molecules that cause damage to cells and their death.

Cells of the gastrointestinal tract, reproductive and hematopoietic systems are especially sensitive to them. Radioactive irradiation disrupts their work and causes nausea, vomiting, stool disturbances, and fever. By acting on the tissues of the eye, it can lead to radiation cataract. The consequences of ionizing radiation also include damage such as vascular sclerosis, impairment of immunity, and a violation of the genetic apparatus.

The system of transmission of hereditary data has a fine organization. Free radicals and their derivatives are capable of disrupting the structure of DNA - the carrier of genetic information. This leads to the emergence of mutations that affect the health of subsequent generations.

The nature of the effect of radioactive radiation on the body is determined by a number of factors:

• type of radiation;
• radiation intensity;
• individual characteristics of the organism.

The results of radiation exposure may not appear immediately. Sometimes its consequences become noticeable after a considerable period of time. Moreover, a large single dose of radiation is more dangerous than long-term exposure to low doses.

The absorbed amount of radiation is characterized by a quantity called Sievert (Sv).

• The normal background radiation does not exceed 0.2 mSv / h, which corresponds to 20 microroentgens per hour. When a tooth is X-rayed, a person receives 0.1 mSv.

• The lethal single dose is 6-7 Sv.

Application of ionizing radiation

Radioactive radiation is widely used in technology, medicine, science, military and nuclear industries and other spheres of human activity. The phenomenon underlies such devices as smoke detectors, power generators, icing alarms, and air ionizers.

In medicine, radioactive radiation is used in radiation therapy for the treatment of cancer. Ionizing radiation has made it possible to create radiopharmaceuticals. With their help, diagnostic examinations are carried out. On the basis of ionizing radiation, devices are arranged for the analysis of the composition of compounds, sterilization.

The discovery of radioactive radiation was without exaggeration revolutionary - the use of this phenomenon brought humanity to a new level of development. However, this also caused a threat to the environment and human health. In this regard, maintaining radiation safety is an important task of our time.