What is the absorbed dose of radiation?

This article is devoted to the topic of absorbed radiation dose (ionization), ionizing radiation and their types. It contains information on diversity, nature, sources, methods of calculation, units of absorbed radiation dose, and much more.

The concept of absorbed dose of radiation

The dose of radiation is a value that is used by such sciences as physics and radiobiology in order to assess the extent to which radiation of ionizing type affects the tissues of living organisms, processes of their vital activity, and also substances. What is called the absorbed dose of radiation, what is its significance, form of influence and variety of forms? It is mainly represented in the form of interaction between the medium and ionizing radiation, but is called the ionization effect.

The absorbed dose of radiation has its own methods and units of measurement, and the complexity and diversity of processes under the influence of radiation give rise to a certain species diversity in the forms of the absorbed dose.

Ionizing form of radiation

Ionizing radiation is a stream of different types of elementary particles, photons or fragments formed as a result of atomic fission and capable of causing ionization in matter. Ultraviolet radiation, like the visible form of light, does not apply to this kind of radiation, nor does it include infrared radiation and radio frequencies, which is due to their small amount of energy, which is not enough to create atomic and molecular ionization in the ground state.

Ionizing form of radiation, its nature and sources

The absorbed dose of ionizing radiation can be measured in different SI units, and depends on the nature of the radiation. The most significant types of radiation: gamma radiation, beta particles of positrons and electrons, neutron, ionic (including alpha particles), X-ray, electromagnetic with short waves (high-energy photons) and muonic.

The nature of the sources of ionizing radiation can be very diverse, for example: spontaneous radionuclide decay, thermonuclear reactions, cosmic rays, artificially created radionuclides, nuclear-type reactors, particle accelerators, and even an X-ray apparatus.

How does exposure to ionizing radiation

Depending on the mechanism by which the substance interacts with ionizing radiation, it is possible to distinguish the direct flow of particles of a charged type and the radiation that acts indirectly, in other words, the photon or proton flux, of the neutral particles of the flow. The formation device makes it possible to isolate the primary and secondary form of ionizing radiation. The power of the absorbed radiation dose is determined according to the type of radiation to which the substance is exposed, for example, the force of the effective dose of rays from space on the earth's surface, outside the shelter, is 0.036 μSv / h. It is also worth noting that the type of measurement of the dose of radiation and its index depend on the sum of a number of factors, speaking of cosmic rays, it also depends on the latitude of the geomagnetic form and the position of the cycle of eleven-year activity of the sun.

The energy range of ionizing particles is in the range of values from a couple of hundred electron volts and reaches the values of 10 ^15-20 electron volts. The length of the run and the ability to penetrate can vary greatly, and lie within a few micrometers, up to thousands or more kilometers.

Acquaintance with the exposure dose

The ionization effect is considered to be the main characteristic of the form of interaction of radiation with the medium. At the initial period of the formation of radiation dosimetry, the study was mainly studied, the electromagnetic waves of which were within the limits of the parameters between ultraviolet and gamma radiation, because it is widespread in the air. Therefore, the quantitative measure of the radiation for the field was the level of air ionization. Such a measure became the basis for creating an exposure dose, determined by the ionization of air under conditions of normal atmospheric pressure, while the air itself must be dry.

The exposition absorbed dose of radiation serves as a means of determining the ionizing possibilities of X-ray and gamma-ray radiation, shows the radiated energy that, having undergone the transformation, has become the kinetic energy of charged particles in the proportion of atmospheric air mass.

The unit of measurement of the absorbed radiation dose for the exposure type is a pendant, a component of the SI system divided by kg (Cl / kg). Type of non-system unit of measure - X-ray (P). One pendant / kg corresponds to 3876 roentgens.

Absorbed amount

Absorbed dose, as a clear definition, became necessary for a person due to the variety of possible forms of exposure of a radiation to the tissues of living beings and even non-living structures. Expanding, a certain range of ionizing species of energy, showed that the degree of influence and impact can be the most diverse and not subject to the usual definition. Only a specific amount of absorbed radiation energy of ionizing type can give rise to chemical and physical changes in tissues and substances subjected to irradiation. The very number necessary to trigger such changes depends on the type of radiation already. The absorbed dose of i-tion arose precisely for this reason. In fact, it is an energy value that has been absorbed by a unit of matter and corresponds to a ratio of the energy of the ionizing type that was absorbed and the mass of the subject or object absorbing radiation.

Measure the absorbed dose with a unit of gray (Gy) - an integral part of the C system. One gray is the dose that can transmit one joule of ionizing radiation to 1 kilogram of mass. Rad is an off-system unit of measure, with a value of 1 Gy corresponds to 100 rad.

Absorbed dose in biology

Artificial irradiation of tissues of animal and vegetable origin clearly demonstrated that different types of radiation, being in the same absorbed dose, can in different ways influence the organism and all the biological and chemical processes taking place in it. This is due to the difference in the amount of ions produced by lighter and heavier particles. For the same path along the tissue, the proton can create ions more than the electron. The more closely the particles are collected as a result of ionization, the more damaging the radiation will be to the organism, under the conditions of the same absorbed dose. It was in accordance with this phenomenon, the difference in the strength of the effect of various types of radiation on the tissue, that the designation of an equivalent dose of radiation was introduced into use. The equivalent dose of absorbed radiation is the data on the radiation received by the body, calculated by multiplying the absorbed dose rate and the special coefficient, which is called the relative biological efficiency factor (RBE). But it is also often referred to as a quality factor.

Units of absorbed radiation dose of equivalent type are measured in SI, namely in sievert (Sv). One Sv is equal to the corresponding dose of any radiation that is absorbed by one kilogram of tissue of biological origin and causes an effect equal to 1 Gy of photon-type radiation. Baer - is used as an off-system measuring indicator of the biological (equivalent) absorbed dose. 1 Sv corresponds to one hundred beers.

Effective dosage form

The effective dose is an indicator of the magnitude that is used as a measure of the risk of long-term effects of human exposure, its individual parts of the body from tissues to organs. This takes into account his individual radiosensitivity. The absorbed dose of radiation is equal to the product of the biological dose in parts of the body for a certain weighted coefficient.

Different human tissues and organs have a different radiation susceptibility. Some organs may, at a single value of the equivalent absorbed dose rate, be more likely to develop cancer than others, for example, the chance of such a disease in the thyroid is less than in the lungs. Therefore, a person uses the created coefficient of radiation risk. CRC is a tool for determining the dose of i-tion affecting the organs or tissues. The total indicator of the degree of effect on the body of the effective dose is calculated by multiplying the number of the corresponding biological dose in the CRC of a particular organ, tissue.

The concept of a collective dose

There is the notion of a group dose of absorption, which is the sum of the individual set of effective dose values in a particular group of subjects over a certain time interval. Calculations can be made for any settlements, including states or whole continents. To do this, multiply the average effective dose and the total number of subjects exposed to radiation. Measure such an indicator of the absorbed dose with the help of man-sievert (chel-Sv.).

In addition to the above-mentioned forms of absorbed doses, the following are distinguished: a committal, threshold, collective, preventable, maximum permissible biological dose of gamma-neutron radiation, lethal-minimal.

The force of the dose and unit of measure

The indicator of the intensity of irradiation is the substitution of a specific dose for the influence of a certain radiation for a time measuring unit. This value is inherent in the difference in the dose (equivalent, absorbed, etc.) divided by the unit of time. There are many specially created units.

The absorbed dose of radiation is determined by a formula suitable for a particular radiation and the type of absorbed amount of radiation (biological, absorbed, exposure, etc.). There are many ways to calculate them based on different mathematical principles, and different measuring units are used. Examples of measuring units are:

1. The integral view is a gray-kilogram in SI, outside the system it is measured in rad grams.
2. The equivalent form is a sievert in the SI, outside the system it is measured - in peers.
3. The exposition view is a pendant-kilogram in SI, outside the system it is measured in x-rays.

There are other measuring units corresponding to other forms of absorbed radiation dose.

conclusions

Analyzing these articles, we can conclude that there are many types, both the ionizing ionization itself, and the forms of its effect on substances of living and inanimate nature. All of them are measured, as a rule, in the system of SI units, and each type corresponds to a certain system and non-system measuring unit. Their source can be the most diverse, both natural and artificial, and the radiation itself plays an important biological role.