Dosimetry is an applied branch of nuclear physics. He is engaged in the study of ionizing radiation, as well as the moments associated with them - the strength of penetration, protection, evaluation methods. This is a very important area that deals with safety issues when working with nuclear elements.
Introduction
Dosimetry is an activity aimed at studying radiation, its power, the accumulation of results in organisms and objects, as well as the consequences. This topic is very broad. Of greatest interest is the amount of ionizing radiation energy that is absorbed by a unit mass of the irradiated medium. The numerical value that allows you to display the scale of the process is called briefly - the dose. Its power is the amount of radiation that occurs per unit of time. The main task that dosimetry is designed to perform is to determine the value of the amount of ionizing radiation energy interacting with various media and tissues of a living organism. Applied value of thissection of nuclear physics can be characterized in the following paragraphs:
- Allows quantitative and qualitative assessment of the biological effect of external and / or internal irradiation of the body for various doses of ionizing radiation.
- Makes it possible to form the basis for taking measures to ensure an adequate level of radiation safety in the case of work with radioactive substances.
- Used to detect the source of radiation, determine its type, amount of energy, degree of impact on surrounding objects.
Definition
Dosimetry is a tool for tracking the ability of elementary nuclear particles to make spontaneous transitions between different states or even into other atoms. After all, it is in this case that the emission of particles (electromagnetic waves) is observed. Different types of process produce different results. The generated radiation can differ in its penetrating ability, as well as the specifics of the effect on the human body. Moreover, it should be noted that this is usually meant in a negative way.
How is research done?
Dosimetry methods involve the use of specialized equipment. Alas, people do not have any organs that would allow us to talk about the problematic nature of certain places. And if a person begins to guess about something by external signs, then, very likely, this knowledge is already too late. Equipment used - indicators,dosimeters, radiometers, spectrometers - allows you to get a complete picture of the current situation within the framework of your goals. After all, it is always necessary to know what exactly is being measured - beta, gamma or neutron radiation. Alpha can be discounted as it has low penetration, other species will be able to kill a human before any significant damage is done to them.
Norma
If we talk about the recommended rates, they are only 20 microroentgens per hour. Although it should be noted that people can easily live for decades even where the radiation background is thousands of microR/h! This situation is due to the fact that the human body has good indicators of resistance and removal of radionuclides. But if you increase the dose, radiation, then the amount of damage increases. Already starting with a dose of 100 Rad, a person earns mild radiation sickness. As you increase, the amount of damage received increases. And upon reaching the range of 500-1000 Rad, the person quickly dies. A dose over one thousand provides instant death.
Calculation of values
And what are these indicators? To determine radioactivity, ionizing radiation dosimetry uses quite a few non/system units. What does it look like in practice? To characterize radioactivity directly, the number of decays of the atomic nucleus per unit time is used. Measured in becquerels. 1 Bq is equal to one decay ingive me a sec. But in practice, it is more convenient to use the non-systemic unit of curie, which is equal to 37 billion becquerels. They are used to determine the concentration of nuclides in air, soil, water or the volume of a substance. To calculate the absorbed dose, indicators such as grays are used. They show how much energy has been absorbed by a certain substance or living organism. The off-system analogue of this unit is the above-mentioned glad. Roughly speaking, they are related as follows: 1 Gy=100 R. The absorbed dose rate is measured in grays (rads) per second. But this is not all the parameters that you need to know when calculating. The number of charges (the total electronic value of ions) that have arisen during irradiation in the environment is called the exposure dose. It is expressed in coulombs per kilogram. Radiation dosimetry provides for the presence of an off-system unit in this case as well. This is the X-ray already mentioned above and its multiple marching (milli- and micro-). They are related as 1 P=2.58 x 107 C / kg. And the last one is the equivalent dose. This value is used to represent the biological effect that occurs when radiation occurs in a living organism. The sievert and its marching ones are used as a system unit. The use of rem is also common. 1 Sv=100 rem. By the way, 100 R is also equal to 1 Sv.
Let's say a word about protection
The basics of dosimetry would be incomplete without considering protection options. There are a number of basic approaches:
- Shielding. One of the main ways to prevent the processirradiation. Based on the use of effective materials that trap radioactive particles.
- Distance. Moving away from the radiation source is the best remedy. When choosing a specific distance, it is necessary to focus on intensity, terrain and climatic conditions.
- Time. This is not so much protection as a reduction in influence and derivative consequences. The less time a person spends near the source, the better his affairs will be.
- Special funds. Materials and preparations (water / food / medicines) that reduce the impact on the body. The latter also contribute to the removal of radionuclides.
Here, in general terms, and all that a person needs to know.
