Physico-Technical Institute Research Articles

Ausferritic (bainitic) cast iron: Harmonization of international standard ISO 17804 in application to the conditions of Belarus

The experience of the Physico-technical Institute (PhTI) of the National Acdemy of Sciences of Belarus in the harmonization of international standard ISO 17804 (Founding – Ausferritic spheroidal graphite cast irons – Classification) and development of the Belorussian analogue STB ISO is described. The reasons for the choice of austempered ductile iron (ADI) as an object for standard harmonization are presented: it is the most promising cast iron in comparison with gray and classical ductile iron. The work procedure on harmonization is described: how to include the task into the State Plan on standardization, specificity of translation of the text, peculiarities of with state organizations responsible for approbation of standards such as Belorussian Institute for Standardization and Certification (BelGISS) and State Committee on Standards (Gosstandart), writing a summary of external reviews, working with critical comments from potential users. It is outlined that any foreign standard does not exists independently but is closely connected with at least 10 to 20 other standards. Thus, harmonization necessitates coordination with other standards and sometimes even with handbooks by adding annexes to the main text. The importance of a proper choice of the standard status is outlined: identical (ID) or modified (MOD). Developing an identical standard is prestigious but difficult because is requires harmonization of all the referenced standards, which is a very labor-consuming procedure. It is argued that the most suitable is ‘intermediate’ variant: adopting the authentic text of the international standard (in high-quality translation) but with annexes reflecting national specificity in this area. As a result, a harmonized standard is developed which, for the first time in Belarus, standardize the tensile strength of 800 MPa in combination with the elongation of 10 % and the tensile strength of 1400 MPa in combination with the elongation of 1 % for cast irons.The annual demand for ADI in Belarus is estimated as about 10,000 ton. It is shown that in Belarus, where about 60 industrial enterprises have a foundry and almost every engineering plant has a heat-treatment shop, austempered ductile cast (ADI), which features a high strength, can successfully compete with rolled steel in certain applications.

60 Years of neutral particle analysis: from early tokamaks to ITER

Academician A. D. Sakharov’s idea concerning the emission of atomic flux from hot plasma (1951) inspired scientists of A. F. Ioffe Physico-Technical Institute to create the first in the world instrument called Neutral Atom Analyzer in 1960 and then in 1961 to use it successfully on the Alpha device (USSR, 1958–1963). Now the analysis of fluxes of fast atoms referred to as Neutral Particle Analysis (NPA) is one of the main diagnostic methods for the ion component of plasma in tokamaks, stellarators, and other devices. NPA provides a unique opportunity for studying the ion distribution functions, ion temperatures and hydrogen isotope ratio in hot plasma. Neutral particle analyzers developed at the Ioffe Institute were widely used in the USSR until the late 1970s, and afterwards began to be employed worldwide. Since then, most of the information on the ion distribution functions and the behavior of fast ions in fusion plasma is obtained from NPA measurements on all leading magnetic confinement fusion systems worldwide. The specialized complex of atom analyzers currently being created at the Ioffe Institute is included in the primary list of ITER diagnostics. The integration of this complex on ITER is expected to begin in 2025.

Founders. Our Compatriots. Academician Viktor Grygorovych Baryakhtar (Curriculum Vitae)

Academician of the National Academy of Sciences of Ukraine Viktor Grygorovych Baryakhtar was one of the first students of Academician Alexander Ilyich Akhiezer. He has made his career from a junior researcher at the Kharkiv Physico-Technical Institute to the first Vice-President of the National Academy of Sciences of Ukraine. The Kharkiv Physico-Technical Institute is the basis of his scientific school, which was further developed in Donetsk and Kyiv. V.G. Baryakhtar is our countryman belonging to a cohort of famous scientists who embody a selfless service for the good of Ukraine.

Chronology of the Ioffe Institute’s Century in Documents from the Archive of the Ioffe Physico-Technical Institute. The Beginning

Chronology of the Ioffe Institute’s Century in Documents from the Archive of the Ioffe Physico-Technical Institute. The Beginning

It's Worth Remembering: "This Never Was Not in The USSR". - Ukraine, Kharkov, UPTI

On the eve of the 90th anniversary of the National Scientific Center Kharkov Institute of Physics and Technology (hereinafter referred to as NSC KIPT) it seems appropriate to recall both its background and pay tribute to the legendary founders of the Ukrainian Physicotechnical Institute (hereinafter - UFTI), who in the 30 years of the last century laid the cornerstone in the foundation of the world fame of the UFTI - NSC KIPT.

Prospects for solar energy in Russia

Solar energy is one of the most promising industries of renewable power engineering. In Russia, the large-scale development of solar engineering is related to the launch of the production of thin-film solar modules based on amorphous silicon at Hevel LLC in February 2015. This company is qualified to create a full-fledged high-tech solar energy industry as an alternative to traditional power sources. Its activity is aimed at improving the efficiency, reducing the production cost, and expanding the scope of application of solar modules. In order to support and develop this industry, the Research and Development Center for Thin-Film Technologies started to operate under the Ioffe Physicotechnical Institute in 2012, its main goal being to improve the key parameters of solar modules based on amorphous silicon in the interests of Hevel LLC.

The Blue LED Nobel Prize: Historical context, current scientific understanding, human benefit

The Blue LED Nobel Prize: Historical context, current scientific understanding, human benefit

Tailoring the Fulde‐Ferrell‐Larkin‐Ovchinnikov state

–to80mmtimes7mm,andcor-respondingly its thickness to 10 nm,and you have an idea about the pre-cision and control necessary to cre-ate thinfilmsin experimentslike theone published recently in Annalender Physik by Jan-Michael Kehrleand co-workers [1]. The motivationforcreatingsuchextraordinarilythinfilms over comparatively large areaswas a prediction that if a thin layerof a conventional superconductor issandwiched between two ferromag-netic films, then the superconduct-ing transition temperature of thistrilayer structure, after initially be-ing suppressed, would show a re-entrance behaviour when the thick-ness of one or both of the ferromag-neticlayers isvaried.The mechanism for such a re-entrant behaviour of the supercon-ducting critical temperature can ul-timately be traced back to the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO)effect. Peter Fulde and Richard Fer-rell, working at the time at the Uni-versity of Maryland, published theirarticle in August 1964 in Physical Re-view B (Ref. 3 in [1]). Independently,working at the Moscow Physico-Technical Institute, Anatoly Larkinand Yuri Ovchinnikov published inSeptember1964anarticleaboutsim-ilar effects in Zhurnal Eksperimen-tal’noi i Teoricheskoi Fiziki (whichappeared translated in March 1965in SovietPhysics JETP) (Ref.4 in[1]).Figure (online color at: www.ann-phys.org) IllustrationoftheFulde-Ferrell-Larkin-Ovchinnikov effect, leading tospatial oscillations as well as to singlet-tripletmixingofthesuperconductingpairamplitudesinaferromagnet.The main physical mechanismof the FFLO effect is described inFig. 1 (modified after [2]). Considersuperconductivity in a weakly spin-polarised ferromagnetic material.Electronic spin bands are shiftedwith respect to each other by anamount 2

Benchmark of coupling codes (ALOHA, TOPLHA and GRILL3D) with ITER-relevant Lower Hybrid antenna

In order to assist the design of the future ITER Lower Hybrid launcher, coupling codes ALOHA, from CEA/IRFM, TOPLHA, from Politecnico di Torino, and GRILL3D, developed by Dr. Mikhail Irzak (A.F. Ioffe Physico-Technical Institute, St. Petersburg, Russia) and operated by ENEA Frascati, have been compared with the updated (six modules with four active waveguides per module) Passive-Active Multi-junction (PAM) Lower Hybrid antennas. Both ALOHA and GRILL3D formulate the problem in terms of rectangular waveguides modes, while TOPLHA is based on boundary-value problem with the adoption of a triangular cell-mesh to represent the relevant waveguides surfaces. Several plasma profiles, with varying edge density and density increase, have been adopted to provide a complete description of the simulated launcher in terms of reflection coefficient, computed at the beginning of each LH module, and of power spectra. Good agreement can be observed among codes for all the simulated profiles.

Measurement of the single-shot pulse energy of a free electron laser using a cryogenic radiometer

The absolute single-shot pulse energy of the SPring 8 extreme ultraviolet (EUV) free electron laser (FEL) was measured using a cryogenic radiometer with a relative standard uncertainty of 3%. The temperature change of the cavity in the cryogenic radiometer caused by an incident FEL pulse was determined using a lock-in amplifier and an ac Wheatstone bridge. The measured pulse energies were compared with a gas-monitor detector developed by Physikalisch-Technische Bundesanstalt/Deutsches Elektronen-Synchrotron/Ioffe Physico-Technical Institute (Ioffe) at a wavelength of 51.3 nm at the SPring-8 EUV-FEL in a shot-to-shot mode. The pulse energies measured using the two detectors agree within 2.0%.

A 16 × 16 hybrid matrix array detector for visualizing XUV plasma radiation

A prototype of a hybrid matrix detector for ultrafast plasma visualization is designed. It uses silicon XUV photodiodes made by the unique technology of the Ioffe Physicotechnical Institute, Russian Academy of Sciences. The principal 16 × 16-format hybrid module consists of eight submodules with 2 × 16-format linear matrices integrated with a 32-channel preamplifier and four fast multiplexers with eight channels. The module is designed to ensure the possibility of integrating into large-format matrices. The data acquisition system consists of eight synchronous 12-bit 4-channel analog-to-digital converter modules with a 40-MHz maximal digitization frequency and reads a complete frame for <1 μs. Each channel has a 64-Mb vehicle-borne memory limiting the data accumulation period to a 0.8-s value, when the rate is at maximum.

Preliminary characterization of semiconductor detectors in the soft X-ray range using synchrotron radiation from the VEPP-4 storage ring

A photodiode developed at the Ioffe Physico-Tech nical Institute (St. Petersburg) and referred to in the literature as the SPD has been preliminarily calibrated by the primary-detector-based method. The possibility of application of SPD photodiodes as radiometric detectors has been investigated. The AXUV-100 photodiode (IRD Inc., United States) was used as a primary detector. The radiation strength of both detectors has been tested. It was revealed that, being more radiation-resistant, the SPD had radiometry characteristics that were not worse than those of the AXUIV-100.

Radiometric comparison for measuring the absolute radiant power of a free-electron laser in the extreme ultraviolet

At the new SPring-8 extreme ultraviolet free-electron laser in Japan, a radiometric comparison between a gas-monitor detector from Physikalisch-Technische Bundesanstalt/Deutsches Elektronen-Synchrotron/Ioffe Physico-Technical Institute (Ioffe) and a cryogenic radiometer from National Institute of Advanced Industrial Science and Technology was carried out. Radiant power in the range between 30 µW and 350 µW was measured at the wavelengths of 51.3 nm, 56.1 nm and 61.2 nm. The results obtained with the two different detectors agree within 2.6%, which is well below their combined relative standard uncertainty, which varies from 4.1% to 5.5%.

Variations in the atomic oxygen 630 nm emission intensity related to orography

The spatial variations in the emission intensity, related to internal gravity waves (IGWs) generated in the troposphere when the air flows around the Kopet Dagh mountain range, and the regularities of these variations have been detected for the first time based on the photometric measurements of the spatial distribution of the atomic oxygen 630 nm emission intensity, performed in 1967 at Vannovskii station of the Physicotechnical Institute, Academy of Sciences of the Turkmen SSR.

Neutral atom analyzers for diagnosing hot plasmas: A review of research at the ioffe physicotechnical institute

Research on neutral particle diagnostics of thermonuclear plasmas that has been carried out in recent years at the Ioffe Physicotechnical Institute of the Russian Academy of Sciences (St. Petersburg, Russia) is reviewed. Work on the creation and improvement of neutral atom analyzers was done in two directions: for potential applications (in particular, on the International Thermonuclear Experimental Reactor, which is now under construction at Cadarache in France) and for investigation of the ion plasma component in various devices (in particular, in the largest tokamaks, such as JET, TFTR, and JT-60). Neutral atom analyzers are the main tool for studying the behavior of hydrogen ions and isotopes in magnetic confinement systems. They make it possible to determine energy spectra, to perform the isotope analysis of atom fluxes from the plasma, to measure the absolute intensity of the fluxes, and to record how these parameters vary with time. A comparative description of the analyzers developed in recent years at the Ioffe Institute is given. These are ACORD-12/24 analyzers for recording 0.2–100-keV hydrogen and deuterium atoms with a tunable range of simultaneously measured energies, CNPA compact analyzers for a fixed energy gain in the ranges 80–1000 eV and 0.8–100 keV, an ISEP analyzer for simultaneously recording the atoms of all the three hydrogen isotopes (H, D, and T) in the energy range 5–700 keV, and GEMMA analyzers for recording atom fluxes of hydrogen and helium isotopes in the range 0.1–4 MeV. The scintillating detectors of the ISEP and GEMMA analyzers have a lowered sensitivity to neutrons and thus can operate without additional shielding in neutron fields of up to 109 n/(cm2 s). These two types of analyzers, intended to operate under deuterium-tritium plasma conditions, are prototypes of atom analyzers created at the Ioffe Institute for use in the International Thermonuclear Experimental Reactor. With these analyzers, a number of new results have been obtained in recent years in various devices. Some results are presented from investigation of ions in the Globus-M spherical tokamak, the W7-AS stellarator, and the JET tokamak by means of the analyzers developed at the Ioffe Institute. Challenges and opportunities for applying these diagnostics in the International Thermonuclear Experimental Reactor project are discussed.

Experimental and numerical investigation into the supersonic flow of a weakly ionized plasma around a dihedral angle: Magnetohydrodynamic control of the flow pattern and heat fluxes toward the wall

The results of experimental and numerical investigations into magnetohydrodynamic actions on the supersonic flow of a weakly ionized xenon plasma around a wedge are presented. The conditions of numerical simulation correspond to the conditions of experiments carried out on the Bol’shaya shock tube at the Ioffe Physicotechnical Institute.

Holographic diagnostics of the plasma: A review

A review of works concerning holographic diagnostics of the plasma that have been conducted in the laboratory of plasma optics at the Ioffe Physico-Technical Institute since 1966 is presented. The potential and features of holographic diagnostics as applied to different plasma objects are discussed. The results of investigations into the laser-induced spark in gases and current sheets forming in 2D and 3D magnetic fields with X lines are reported.

Развитие в ННЦ «ХФТИ» методов направленного изменения структуры и свойств конструкционных материалов при активизации релаксационных процессов: обзор, посвященный 80-летию Национального научного центра «Харьковский физико-технический институт»

Развитие в ННЦ «ХФТИ» методов направленного изменения структуры и свойств конструкционных материалов при активизации релаксационных процессов: обзор, посвященный 80-летию Национального научного центра «Харьковский физико-технический институт»

Development of a technique for high-speed γ-ray spectrometry

A technique for high-speed γ-ray spectrometry was developed for γ-ray diagnostic experiments on the ITER tokamak and tested at the Ioffe Physico-Technical Institute on the cyclotron and the GLOBUS-M and TUMAN-3M tokamaks. This technique was used to upgrade the γ-ray diagnostic system of the JET tokamak. It was shown by the tests that the new technique compares favorably to the traditional one in that it allows the limiting counting rate of the spectrometer to be increased by at least an order of magnitude without noticeable deterioration of its energy resolution.

Testing the neutron attenuator based on 6LiH for γ-ray diagnostics of plasmas in the JET tokamak

A 6LiH attenuator of a neutron flux incident on a detector is used to reduce the γ-ray background induced by neutrons in the detector material. This attenuator has been tested during experiments with deuterium (DD) plasmas on the JET tokamak. A specimen of the neutron attenuator with dimensions of ⊘30 × 300 mm has been developed by the Russian Academy of Sciences’ Ioffe Physico-Technical Institute and inserted into a vertical collimator used for γ spectrometry of plasmas. To compare γ-ray spectra recorded with and without the 6LiH attenuator being mounted, identical discharges with heating of the DD plasma by a neutral particle beam have been selected. For γ rays with energies of 3 MeV can be attributed to the transparency of the 6LiH attenuator for γ rays. This portion of the spectrum is due to γ radiation of the plasma and γ rays induced by neutrons in the constructional materials of the tokamak. To estimate the efficiency of the 6LiH attenuators as a mandatory component of the ITER γ-ray diagnostic system, it is necessary that measurements be taken in deuterium-tritium (DT) discharges.