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- Priming coating: "glowing" dosimeter tablets will detect dangerous radiation
Priming coating: "glowing" dosimeter tablets will detect dangerous radiation
A new generation of high-precision dosimeters has been created in Russia. They are based on "pills" equivalent to human tissues in terms of the intensity of radiation dose accumulation. They glow when heated, depending on the intensity of the radiation. The devices can work independently for five days and are equipped with wireless charging. The devices are also resistant to falling and protected from erroneous registration of mechanical influences (for example, when rubbing against clothing). In addition, the developers have designed a reader that makes it possible to simultaneously process data from 50 dosimeters. The devices are superior to their foreign counterparts in terms of performance and cheaper in price.
How is the accumulated radiation dose measured?
A new generation of personal dosimeters has been developed in Russia, which make it possible to measure with high accuracy the dose of occupational exposure of employees of nuclear power plants and other radiation-hazardous facilities. The development was carried out by engineers from the Specialized Scientific Research Institute of Instrument Engineering (SNIIP, part of the Rosatom State Corporation).
As the experts explained, the accumulated dose is the amount of ionizing radiation energy that is absorbed by a substance or material over a certain period of time. For employees of nuclear power plants, the norm is no more than 20 mSv (millisieverts) per year, and for the population — up to 1 mSv. For comparison, with an accumulation of a dose of 1000 mSv, radiation sickness can occur, and with 4000-5000 mSv— death.
— The development is a device that every employee carries with him while staying at a nuclear facility. Its main element is phosphor detectors in the form of tablets, created on the basis of magnesium and boron compounds," Andrey Gordeev, chief designer of SNIP, told Izvestia.
He explained that the pills are equivalent to human tissues in terms of the intensity of radiation dose accumulation. They accumulate ionizing radiation, and then, when placed in a reader and heated to 350 ° C, they convert it into light. The brighter the pills "burn", the greater the dose of accumulated radiation. The light flow is captured by photomultiplier sensors, and the electronics convert the data into the amount of the accumulated dose.
As the designer noted, one of the advantages of dosimeters is that the annealing of the detector tablets is carried out in normal "room" conditions. In contrast, foreign analogues require an inert atmosphere, which is maintained by pumping nitrogen, a gas that almost does not react with other substances. However, this requires special equipment, which complicates and increases the cost of the process.
How to prevent breakdowns and false alarms
Domestic dosimeters are characterized by increased resistance to extreme factors, said Andrey Gordeev. In particular, they are designed for operation at temperatures from -50 °C to +60 °C, which allows them to be used in various climatic conditions where Russian—designed nuclear power plants are being built, from equatorial latitudes to the Arctic.
The developers paid special attention to the stability of the material characteristics of the detector tablet, for which they conducted large-scale and long-term tests, he added. As a result, it was possible to realize the possibility of using tablets for about 500 cycles. In addition, the devices do not need to be calibrated, and the entire cycle of production processes (from reagent synthesis to assembly of dosimeters) is concentrated in one place. This reduces the risks of incorrect operation of the devices.
— About 50,000 dosimeters are used in Russia, but the market is dominated by foreign companies, as it happened historically. In the coming years, Russia will have to completely upgrade its radio measuring equipment, since 10% of foreign dosimeters fail every year, and no new ones are supplied," said Andrey Gordeev.
It is assumed that, complete with individual dosimeters, specialized devices that take instrument readings will be supplied to enterprises. They are also developed by SNIP specialists. Such readers have the ability to automatically load detectors into the signal removal area, he added.
Where dosimeters are used
— Russian dosimeters are not inferior to foreign ones, and in many cases surpass them. The so—called tablets are a special kind of cumulative dosimeters that should react to radiation in much the same way as human living tissue. There is even such a term as tissue equivalent analogues," Alexey Ozerov, a test engineer at the Radar Design Bureau, explained to Izvestia.
According to him, the introduction of the development into serial production and operation at nuclear power plants may face difficulties, since the devices are related to human safety. At the same time, tissue equivalent dosimeters are in demand not only at nuclear power plants, but also in medicine, charged particle accelerators, and other branches of science and industry, the expert added.
High—precision portable storage dosimeters of the new generation are necessary and in demand devices, said Olga Tarasova, co-author of the Nasha Lab project and a member of the Coordinating Council for Youth in the Scientific and Educational Fields of the Presidential Council for Science and Education.
In particular, batches of devices may be required to monitor accumulated doses by the population in cases of man-made disasters related to radiation leakage, she stressed. In the near future, they will be useful for classes on the basics of life safety.
— The main difficulties in introducing such devices into mass operation arise from the need to include them in the state register of measuring instruments. Without this, the device cannot be used in serious enterprises. If this issue is resolved, then marketing specific to laboratory and measuring equipment will come into play," explained Tatiana Kulagina, Doctor of Technical Sciences, Professor, Head of the Department of Technosphere and Environmental Safety at Siberian Federal University.
The presented development, in addition to nuclear facilities, will be able to find application in educational and research laboratories, as well as in irradiation and testing facilities, the expert concluded.
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