From the middle of the last century, a new science camethe word is radiation. Its discovery made a revolution in the minds of physicists around the world and allowed us to discard some Newtonian theories and make bold assumptions about the structure of the Universe, its formation and our place in it. But this is all for specialists. The philistines only sigh and try to put together such scattered knowledge about this subject. Complicating the process is the fact that there are quite a few units of radiation, and all of them are valid.
Первый термин, с которым стоит познакомиться, – this is, in fact, radiation. So called the process of radiation of a substance of the smallest particles, such as electrons, protons, neutrons, helium atoms and others. Depending on the type of particle, the radiation properties differ from each other. Radiation is observed either during the decomposition of substances into simpler ones, or during their synthesis.
Radiation Units - these are conditional terms that indicatehow many elementary particles are released from a substance. At the moment, physics operates with seven different units and their combinations. This allows you to describe the various processes occurring with matter.
Radioactive decay - an arbitrary change in the structure of unstable atomic nuclei by the release of microparticles.
Constant decay - This is a statistical concept that predicts the probability of the destruction of an atom for a certain period of time.
Half life - This is the time interval for which half of the total amount of a substance disintegrates. For some elements it is calculated in minutes, and in others for years, even decades.
Units of measurement of radiation are not the only ones that are used to evaluate the properties of radioactive materials. In addition, they use such quantities as:
- activity of the radiation source;
- flux density (number of ionizing particles per unit area).
In addition, there is a difference in describing the effects of radiation on living and nonliving objects. So, if the substance is inanimate, then the following concepts apply:
- absorbed dose;
- Exposure dose.
If the radiation affected the living tissue, then use the following terms:
- equivalent dose;
- effective equivalent dose;
- dose rate.
Units of measurement of radiation are, as alreadyas mentioned above, the conditional numerical values adopted by scientists to facilitate calculations and the construction of hypotheses and theories. Perhaps that is why there is no single generally accepted unit of measurement.
One of the units of measurement of radiation is curie.It does not belong to the system (does not belong to the SI system). In Russia, it is used in nuclear physics and medicine. The activity of a substance will be equal to one curie if in one second 3.7 billion radioactive decays occur. That is, it can be said that one curie is equal to three billion seven hundred million becquerels.
This number was due to the fact that MaryCurie (who introduced this term to science) conducted her experiments on radium and based on its decay rate. But over time, physicists decided that the numerical value of this unit should be tied to another - Becquerel. This allowed to avoid some errors in mathematical calculations.
In addition to the curie, you can often find multiple or long units, such as:
- megacurie (equal to 3.7 per 10 to 16 degrees of becquerel);
- kilcurie (3.7 thousand billion becquerels);
- millicurie (37 million becquerels);
- microcuries (37 thousand Becquerels).
With the help of this unit one can express the volume, surface or specific activity of a substance.
Единица измерения дозы радиации беккерель is a system and is part of the International System of Units (SI). It is the simplest, because radiation activity in one Becquerel means that only one radioactive decay takes place in a substance per second.
It got its name in honor of Antoine HenriBecquerel, a French physicist. The name was approved at the end of the last century and is still used. Since this is a rather small unit, decimal prefixes are used to denote activity: kilo-, milli-, micro-, and others.
Recently, along with Becquerel steelused non-system units such as Curie and Rutherford. One Rutherford equals one million becquerels. In the description of the volume or surface activity can be found the designation Becquerel per kilogram, Becquerel per meter (square or cubic) and their various derivatives.
Radiation unit x-ray is also notis systemic, although it is used everywhere to denote the exposure dose of gamma radiation. One X-ray is equal to a dose of radiation at which one cubic centimeter of air at a standard atmospheric pressure and zero temperature carries a charge equal to 3.3 * (10 * -10). This is equal to two million pairs of ions.
Despite the fact that according to the legislation of the Russian Federationmost non-system units are prohibited; x-rays are used in the labeling of dosimeters. But they will soon cease to be used, since it turned out to be more practical to record and calculate everything in gray and sivert.
Radiation unit of measure rad is outthe SI system is equal to the amount of radiation at which one millionth of a joule of energy is transferred to one gram of substance. That is one happy - this is 0.01 joule per kilogram of matter.
A material that absorbs energy can beas living tissue, and other organic and inorganic substances and substances: soil, water, air. As an independent unit, rad was introduced in 1953 and in Russia has the right to be used in physics and medicine.
This is another measure of the level of radiation,which is recognized by the International System of Units. It reflects the absorbed dose of radiation. It is believed that the substance received a dose of one gray, if the energy that is transmitted with radiation is equal to one joule per kilogram.
This unit got its name in honor ofEnglish scientist Lewis Gray and was officially introduced to science in 1975. According to the rules, the full name of the unit is written with a small letter, but its short designation - with a large one. One gray is equal to a hundred radam. In addition to simple units, in science they use multiple and long-term equivalents of them, such as kilogrey, megagrey, decigree, centigray, microgray, and others.
Radiation unit sievert is usedto designate effective and equivalent radiation doses and also enters the SI system, like gray and becquerel. Used in science since 1978. One sievert is equal to the energy absorbed by a kilogram of tissue after exposure to a single warming of gamma rays. The name of its unit was in honor of Rolf Sievert, a scientist from Sweden.
Судя по определению, зиверты и греи равны, то there are equivalent and absorbed doses have the same size. But the difference between them is still there. In determining the equivalent dose, it is necessary to take into account not only the quantity, but also other radiation properties, such as wavelength, amplitude, and which particles represent it. Therefore, the numerical value of the absorbed dose is multiplied by the coefficient of radiation quality.
So, for example, with all other things being equalThe absorbed effect of alpha particles will be twenty times stronger than the same dose of gamma radiation. In addition, it is necessary to take into account the tissue coefficient, which shows how organs react to radiation. Therefore, the equivalent dose is used in radiobiology, and the effective dose is used in occupational health (to normalize the effects of radiation).
There is a theory that life on our planetappeared thanks to solar radiation. Units of radiation from a star are calories and watts divided by a unit of time. This was decided because the amount of radiation from the Sun is determined by the amount of heat that objects receive and the intensity with which it comes. The Earth reaches only half a millionth of the total amount of energy emitted.
Radiation from stars is distributed in space withthe speed of light and in our atmosphere will fall in the form of rays. The spectrum of this radiation is quite wide - from "white noise", that is, radio waves, to x-rays. Particles that also fall together with radiation are protons, but sometimes there can be electrons (if the energy release was large).
The radiation received from the sun isthe driving force behind all living processes on the planet. The amount of energy we receive depends on the time of year, the position of the star above the horizon and the transparency of the atmosphere.
If living characteristics are the sameIf tissues are irradiated with different types of radiation (in the same dose and intensity), the results will vary. Therefore, to determine the consequences, only an absorbed or exposure dose is small, as is the case with non-living objects. Units of measurement of penetrating radiation appear on the scene, such as Sievers of Rem and Gray, which indicate an equivalent dose of radiation.
Equivalent is called the dose absorbed by the livingtissue and multiplied by the conditional (tabular) coefficient, which takes into account how dangerous this or that type of radiation. Most often, a sievert is used to measure it. One sievert equals one hundred rams. The greater the coefficient, respectively, the more dangerous the radiation. So, for photons it is a unit, and for neutrons and alpha particles - twenty.
Since the accident at the Chernobyl nuclear power plant in Russia andother CIS countries began to pay special attention to the level of radiation exposure on humans. The equivalent dose from natural sources of radiation should not be higher than five millisievert per year.
Радиоактивные частицы несут в себе заряд энергии, which they transmit to the substance when they encounter it. And the more particles in contact with a certain amount of substance on its path, the more energy it will receive. Its quantity is estimated in doses.
