Applied Physics Researches Division (APRD)

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New publication in peer-reviewed journal

Posted by on Apr 20, 2018

Our new paper has been published in “The Journal of Electronic Materials” monthly peer-reviewed scientific journal (Impact factor: 1.579 (2016))  and is available for downloading: Yeritsyan et al., 2018, Journal of Electronic Materials   Abstract This paper reports the formation of structural defects in the lattice of silicon (n-Si) single crystals, as a result of irradiation by different intensities and pulses of electrons. The samples were studied by means of Hall effect measurements of electro-physical parameters (specifically the concentration of the main charge carriers) as a function of temperature and radiation dose. The role of the radiation current density (pulse height) is discussed, which gives rise to a peculiar behavior in the electrical-physical properties of n-Si. In particular, thermal processes are found not to develop, due to the ultrafast (pulse duration in the range 10−12–10−13s) nature of the incident radiation, which causes an almost “pure” energy interaction to occur between the radiation and the atoms within the crystal, and the formation of cluster defects. A scheme for the time-scale of the formation of these radiation defects is presented. From the dose and temperature dependences of the concentration of main charge carriers, the radiation defects introduction rates were...

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Setting for measuring of the lifetime minority charge carriers of semiconductors

Posted by on Apr 13, 2018

Setting for measuring of the lifetime  minority charge carriers of semiconductors

The lifetime of the minority charge carriers of semiconductors is determined by the method of measuring the decay time constant of the signal of the recombination process of nonequilibrium charge carriers in a semiconductor. Nonequilibrium charge carriers are generated by illumination of a sample with a radiation length of 1.05 μm (for Si), the decay process is detected by microwave absorption at a frequency of 12 GHz and recorded on an oscilloscope. The accuracy of the measurement is ± 10%, the msmeasurement time interval is is from 1μs to 10 μs, the sample size is 10x4x1 mm-3. This is the only method of completely non-destructive non-contact measurement of the lifetime of minority charge carriers of...

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Project: ISTC A-2133p (2015-2017)

Posted by on Apr 5, 2018

Annual Technical Report A-2133, 2016 Final Technical report...

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Project: ISTC A-1605

Posted by on Apr 5, 2018

Project: ISTC  A-1605

Development of High-Efficient Filter Systems on the Basis of Super-Thin Basalt Fiber for Radioactive Aerosols Purification and Creation of a Work Circle for Filters Manufacturing with the Purpose of Their Operation at Nuclear Power Plants  ( ISTC  A-1605) At present, creation of highly effective energy- and resource- saving low-waste and safe technologies for cleaning of environment from radioactive emissions of nuclear-powered industrial enterprises, nuclear power plants and thermonuclear facilities presents undoubtedly an actual problem. Number of participants: 27 Number of publications related to the Project: 10 Number of conferences: 8 (Germany, Moscow, Kiev, Almaaty, Sevastopol, Sochi. Patent: АМ 20110016 The Project implementation has allowed creating of highly efficient filtering system for cleaning radioactive aerosols at nuclear power plants. For this purpose: A new method for obtaining of modified sorbents on the basis of super-thin basalt fiber with significantly enhanced sorption characteristics was offered. A pilot lot of new filters for cleaning of ventilation air from finely dispersed radioactive emissions was manufactured and installed in V2 ventilating system of the Armenian nuclear power plant. Their cleaning efficiency makes 98.4 to 99.6 %, which is comparable to efficiency of the IAEA standards for regular filtering blocks. A technological process of manufacturing filters from super-thin basalt fibers was developed. A technology of regeneration for the used filters after their withdrawal from service was developed.   The offered filters, manufacture of which is based on local raw materials, are economic and two times cheaper than others used till now at the Armenian NPP. It is intended to use, starting from the next 2014 year, the developed modified super-thin basalt fibers for air cleaning from radioactive isotopes in normal operation regime of Armenian NPP.   Success Story At present, one of global environmental problems is creation of highly effective enterprises and devices for processing, recycling and burial places for wastes, life-support equipment. All of them demand new hybrid technologies, which, in turn, demand creation of new functional and constructional materials with rather specific properties. Therefore creation of highly effective energy- and resource-saving low-waste and safe technologies for cleaning of environment from radioactive emissions of nuclear-powered industrial enterprises, nuclear power plants and thermonuclear facilities presents undoubtedly an actual problem. Under the financial auspices of the International scientific and technical centre, significant contribution is made in solution of this problem.             Research of highly effective filtering systems of protection of the population and environment from radioactive emissions from the Armenian nuclear power plant, conducted in A.I. Alikhanian National scientific laboratory (former Yerevan Physical Institute) and in the Research Center For The Problem Of The Non Proliferation Of Mass Destruction Weapons, was supported within the framework of ISTC A-1605 Project financed by Canada. The Project activities were begun in January 2009 in close cooperation with foreign collaborators from AMEC NSS Limited, 700 University Avenue, Toronto, Ontario, Canada. The Project collaborators were recognized leaders in the field of filtering systems, and their participation guaranteed continuity of methodology and technical approach to the Project tasks.             Super-thin basalt fibers...

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New experimental device at Optics and spectroscopy laboratory

Posted by on Nov 6, 2017

New experimental device at Optics and spectroscopy laboratory

Experimental procedure. To carry out one or another type of studies on the effects of solar radiation and the experimental determination of the effectiveness of solar energy concentrators, you need, above all, a source of radiation which spectrum is close to the sun spectrum in outer space or near the Earth’s surface. Therefore, one of the most important components of system test stations is a solar simulator. As is known, considerable remoteness of Sun from Earth leads to the fact that solar rays incident on the objects in cosmic space or on the Earth’s surface in parallel, while the artificial radiation sources are located at relatively short distances from the surface of the test product. Solar simulator (SS) designed to simulate solar radiation. An important requirement of the SS is its minimum impact on the simulation of temperature and humidity regimes in the measuring chamber. SS includes light sources (lamps), forming optical devices (FOD), devices for radiation input into the chamber, reflecting mirror systems, power supplies for lamps, filters, measuring and control devices for simulator and its individual systems, as well as other auxiliary systems. The luminescent properties of the samples were tested using the newly developed experimental installation, LUMEN. The installation (Figure 2) provides ample opportunities for research in the field of fluorescent UV-visible spectroscopy with energy resolution at different temperatures.   Fig. 2.  LUMEN laboratory installation Figure 3 shows the scheme of optical measurements using LUMEN installation. The installation was mounted using standard serial equipment has been collected on the basis of equipment from serial production and two monochromators. To excite luminescence, a primary monochromator was used. In order to eliminate higher orders of diffraction gratings, quartz or LiF filters were arranged on the output window of the primary monochromator. Optical scheme of the primary monochromator provided UV radiation spot size 2 х 0.15 мм2 on the sample. The second monochromator was used for the registration of luminescence in UV and visible spectral regions. At the exit of the monochromator, a solar-blind photomultiplier was arranged to measure luminescence spectra. LUMEN installation operations, regimes of temperature and measurement range selection, were computer controlled, and processing of luminescence spectra was carried using special software. Fig.3 The scheme of LUMEN experimental installation. As a light source, DKsEL 1000-5 ultra-high pressure xenon lamp was used. For this xenon lamp, a high-aperture illuminator was specially made from KU quartz glass. The power of the xenon lamp radiation spectrum (240 nm to 360 nm) was 1,000 kW. The samples under investigation were placed within the working chamber on a copper crystal holder of a blow nitrogen cryostat that provided high vacuum not worse than 2·10– 6 Torr to guarantee the needed purity of the crystal surface at low temperature experiments. The registration system made it possible to measure the luminescence spectra in different spectral points at the selective photoexcitation to 3.5 eV, as well as the luminescence spectra within the range of 1.2 -3.5...

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