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The objectives and scientific tasks of the planned space experiment “Solntse-Terahertz” to be performed onboard the ISS Russian Segment are briefly described in the paper. In particular, the aim of the experiment is to study uninvestigated solar electromagnetic emission in the terahertz domain, in ~ 1012 – 1013 Hz (300-30 µm) frequency range. It is expected to obtain new data on solar active region emission including solar flare emission. These data are necessary to clarify the nature of solar activity and construct physical model of charged particle acceleration in active regions during solar flares and other astrophysical objects. We focus on the telescope optical system design and evaluation of main characteristics of this system. Results of simulations and comparison with the experimental verification of obtained characteristics are presented. A close correlation of the estimations and experimental results was obtained. As a result, main parameters of the telescope optical system of experimental hardware “Solntse-Terahertz” were determined. Key words: Sun, solar flares, terahertz emission, optical system.

Aim To study features of diagnosis and treatment of acute myocardial infarction (AMI) in Russian hospitals, results of the treatment, and early and late outcomes (6 and 12 months after AMI diagnosis); to evaluate the consistence of the treatment with clinical guidelines; and to evaluate patients’ compliance with the treatment.Material and methods The program was designed for 3 years, including 24 months for recruitment of patients to the study. The study will include 10, 000 patients hospitalized with a confirmed diagnosis (I21 according to ICD-10) of ST segment elevation acute myocardial infarction (MI) (STEMI) or non-ST segment elevation MI (NSTEMI) based on criteria of the European Society of Cardiology Guidelines on Forth Universal Definition of Myocardial Infarction (2018). The follow-up period was divided into three stages: observation during the stay in the hospital and at 6 and 12 months following inclusion into the registry. The primary endpoint included cardiac death, nonfatal MI during the hospitalization and after one-year follow-up. Secondary endpoints were 6-months and one-year incidence of repeated MI, heart failure, ischemic stroke, clinically significant hemorrhage, unscheduled revascularization after discharge from the hospital, and the proportion of patients who continue on statins, antiplatelet drugs, and drugs of other groups for 6 months and 1 year.Results The inclusion of patients into the registry started in 2020 and will continue for 24 months. By the time of the article publication (June, 2021), more than 2,000 patients will be included.Conclusion REGION-MI (Russian rEGIstry Of acute myocardial iNfarction) is a multicenter, retrospective and prospective observational cohort study that excludes any interference with the clinical practice. Results of the registry will help to analyze a real picture of medical care provided to patients with myocardial infarction and to schedule ways to improve the situation.

The description and technical characteristics of the gamma-spectrometer installation for the detection of cosmic rays, as designed at the Dolgoprudny scientific station of the Lebedev Physical Institute in cooperation with the Mackenzie University (Sao Paulo, Brazil), are presented. This installation has operated continuously in the CASLEO astronomical complex since 2015. The detector modules of the setup are based on the NaJ (Tl) scintillator, which is 76.2 mm × 76.2 mm high, a Hamamatsu R1307 photomultiplier tube, a high voltage power supply, and a preamplifier. The technique of the experimental calibration of the spectrometer is also presented.

This paper provides a brief description individual elements that can be included in the Solntse–Terahertz scientific apparatus that was designed for the first time to carry out an extra-atmospheric experiment onboard the International Space Station. Its purpose is to measure terahertz electromagnetic radiation both from the quiet Sun and during active processes on the Sun (solar flares, coronal mass ejections, etc.), which is necessary to establish the physical nature of solar activity and solar flares. The possibility is discussed of using optoacoustic converters (Golay cells) as receivers of terahertz radiation, the sensitivity, stability, and response time of which were determined in the course of preliminary laboratory studies under terrestrial conditions.

The optimization of the optical structure of the NICA Collider is presented. The Collider optics settings are given for a working point of 9.44/9.44 and a bare gold nuclei beam with energies of 1, 3, and 4.5 GeV/u. The dynamic aperture simulation and optimization results are given. The tolerance of the magnetic field errors for the Collider structural elements and the closed orbit adjustment precision are discussed.

—This paper presents a description of the new CARPET facility for detecting the charged component of cosmic rays, as well as its technical characteristics; it was designed and installed at the Dolgoprudny Scientific Station of the Lebedev Physical Institute (DNS of the Lebedev Physical Institute). The detecting base of the CARPET facility consists of STS-6 gas-discharge counters combined in 12 units with ten counters in each. The upper counter layer is separated from the lower counter layer by an aluminum filter with a thickness of 7 mm. The integration time of these counters is 1 ms. Continuous monitoring of meteorological data and data on the state of the supply voltage of the facility occur. The results of determining the barometric coefficient for the CARPET and analysis of the first experimental data are also presented.

The article is devoted to the study of digital image quality at different levels of daylight. The quality of the digital image was evaluated by the resolution and contrast of the image in three spectral zones: blue, green and red. The test object for photographing was a white sheet of 594X841mm format with line targets, color scales and an image of an optical step wedge located on it. Line targets were located over the entire area of the sheet, which made it possible to study the image quality over all its area. Digital photography was performed by a NIKON SLR camera and was accompanied by measurements of illumination in the plane of the test object with the measurement of the height of the sun by theodolite. The resolution of the digital camera was measured during the day interval from 3:00 to 22:00. For each hour of shooting resolution was determined by 9 line targets, 8 of which were located on the perimeter of the sheet and one in the center. Spectral profiles on color scales were also obtained for each ur, and the value of contrast on the image of the optical wedge was determined. As a result of the study, an effective daily interval was determined to perform digital shooting from unmanned aircraft for the Moscow region (55°45′07″ W).

The thyroid cancer is the most prevalent oncologic disease of endocrine organs, characterized by multi factorial risk of development. The purpose of the study was to analyze dynamics of indices of thyroid cancer morbidity of population of the Russian Federation, considering gender and age differences in 2008-2018. The increase of "rough" indicator of thyroid cancer morbidity of male population made up to 56.6%, and of female population - 48.3%. The dynamics of standardized indicator in gender contingents was characterized by increasing up to 48.7% in males and up to 43.9% in females. There is an increasing of thyroid cancer morbidity with age and prevalence of the morbidity in females as compared with males in all age categories. The highest morbidity was established in male population aged 65-69 years (8.3 per 100,000 population) and in females aged 55-64 years (27.3 per 100,000 population). In the territories of the Russian Federation, in the gender aspect, variations in thyroid cancer morbidity were established. both in male and female populations, maximal thyroid cancer morbidity was established in the North Western and Siberian Federal Okrugs, and morbidity below national level was registered in the Privolzhskiy and North Caucasian Federal Okrugs. It is necessary to take into account differentiation of the territories of the Russian Federation in terms of the thyroid cancer morbidity in different gender and age groups for development of rational measures of early identification of risk factors, diagnosis and treatment of patients.

Programs for the pre-processing of photographs of beam images on the mask based on Wolfram Mathematica and Origin software are described. Angles of rotation around the axis and in the vertical plane are taken into account in the generation of the file with image coordinates. Results of the emittance calculation by the Pep_emit program written in Visual Basic using the generated file in the test mode are presented.

Crohn's disease is a severe relapsing disease that requires the coordinated work of doctors of various specialties — gastroenterologists, surgeons, radiologists, and endoscopists. The strategy of a multidisciplinary team is economically and clinically viable. The main principles of work in the multidisciplinary team are a recognized need and availability of specialists for each other, regular joint meetings, and presence of local standards and common approaches. The joint work of experts helps to develop an individual plan for the management of patients according to the severity and form of the disease, as well as to prevent complications and new relapses. The article presents a clinical example of the management of a patient with Crohn's disease complicated by perianal lesions. The implementation of the multidisciplinary team concept has prevented the disability of the child.

In this paper the description and technical characteristics of the new instrument for detection of the charged secondary component of cosmic rays named CARPET-ASTANA, designed in the Dolgoprudny Scientific Station of the P.N. Lebedev Physical Institute are presented. This instrument is installed at L. N. Gumilyov Eurasian National University (Nur-Sultan, Republic of Kazakhstan) at the end of 2015. The detectors of the CARPET-ASTANA instrument are gas-discharge counters of the STS-6 type, combined in 12 blocks of 10 counters in each. Each block has two layers. The upper counter layer has separated from the lower counter layer by an aluminum filter with a thickness of 7 mm. The results of determining the barometric coefficient for the CARPET-ASTANA instrument and analysis of the first experimental data are presented in this paper. The issue of detection accuracy is also discussed.

A compact new neutron detector based on SNM-18 neutron counters is described. The first results obtained in ground-based neutron flux measurements are discussed. An array of several such detectors can provide experimental data for investigating high-energy phenomena on the Sun and dynamic processes in the Earth’s atmosphere.

The science projects growth, changing of the efficiency criteria during the project implementation require not only increasing of the management specialization level but also pose the problem of selecting the effective planning methods, monitoring of deadlines and interaction of participants involved in research projects. This paper is devoted to choosing the project management information system for the new heavy-ion collider NICA (Nuclotron based Ion Collider fAcility). We formulate the requirements for the project management information system with taking into account the specifics of the Joint Institute for Nuclear Research (JINR, Dubna, Russia) as an international intergovernmental research organization, which is developed on the basis of a flexible and effective information system for the NICA project management.

The application of plastic cards has been widely increasing in various fields of life, business and education. They have already become up-to-date and convenient attribute of our daily life. There are emerging more and more areas where they can be used in a convenient and practical way. Contactless smart cards can be used in access control in the educational systems. This article gives an overview of existing standards dealing with contactless identification smart-cards. All standards covered in this article are developed by the Federal State Unitary Enterprise VNIINMASH jointly with TC 22 «Information Technology» based on their own authentic Russian translation of international standards.

In the first part of this article we review the challenges associated with erbium–ytterbium doped fibre amplifiers and the design considerations to scale-up the output power and energy using cladding-pumped large-core fibre amplifiers in master-oscillator power-amplifier (MOPA) configuration. Previous results are also given to illustrate this rather successful approach. The second part consists of our latest experimental results with improvements in terms of linewidth and peak power using shorter pulses. Sub-hundred nanosecond pulses with millijoule energy and narrow linewidth were obtained using cascaded fibre amplifiers with large-core fibres. The energy level obtained with such short pulse duration and narrow spectral linewidth is the highest ever reported. System limitations and potential routes for further improvement are also discussed. To cite this article: C. Codemard et al., C. R. Physique 7 (2006).

A tunable high-power cladding-pumped neodymium-doped aluminosilicate fiber laser is demonstrated. The maximum power reached was 2.4 W with a slope efficiency of 41% and a threshold pump power of 1.68 W, both with respect to launched pump power, when cladding pumped by two 808-nm diode pump sources at both fiber ends. The dependence of the tuning range on the fiber length is investigated. The tuning range changed from 922 to 942 nm for a 25-m-long fiber to 908-938 nm with a 14-m-long fiber, because of reabsorption effects. The output linewidth was 0.26 nm in a diffraction-limited beam. Operation on the challenging 0.9-/spl mu/m three-level transition in neodymium-doped double-clad fiber laser was facilitated by a W-type core refractive index profile. This filtered out the unwanted and competing strong transition at 1.06 /spl mu/m while guidance of 0.9 /spl mu/m remained intact.

The results of optimization of the atomic and electronic structure of strained silicon clusters Si51 on a germanium substrate are presented. The interaction of boundary nanocluster atoms with the substrate is studied. The effect of strain and impurities on the distribution of electronic states is analyzed.

Fibre lasers are thin, light-guiding strands of glass only a few times the thickness of a hair which have a tiny core doped with rare-earth materials to absorb the pump radiation and release the stimulated emission at the signal wavelength. Fibre lasers provide unheard of attributes in the laser world – low maintenance, high efficiency, and excellent beam control, and are compact and all-solid-state. Their low cost of ownership will enable industrial laser applications, such as material processing, micro-machining, marking, printing, medicine, etc., which were hitherto thought impractical.

We discuss the dramatic development of high-power fiber laser technology in recent years and the prospects of kilowatt-class-single-frequency fiber sources. We describe experimental results from an ytterbium-doped fiber-based multi-hundred-watt single-frequency, single-mode, plane-polarized master-oscillator power amplifier (MOPA) operating at 1060 nm and a similar source with 0.5 kW of output power, albeit with a degraded beam quality (M2 = 1.6) and not linearly polarized. Experiments and simulations aimed at predicting the Brillouin limit of single-frequency system with athermally broadened Brillouin gain are presented. These suggest that single-frequency MOPAs with over 1 kW of output power are possible. In addition, the power scalability of a simple single-strand fiber laser to 10 kW is discussed

Narrow-linewidth high power pulsed "eye-safe" erbium-ytterbium doped fiber lasers and amplifiers (EYDFA) are ideal source for LIDAR systems, nonlinear optical conversion, and remote sensing thanks to their compactness, versatility and efficiency. However although recent progress has been made, scaling of the energy and peak power of narrow-linewidth pulses presents many challenges. Stimulated Brillouin scattering (SBS) is the major impediment for "single-frequency" pulses. Here, in order to avoid this nonlinear effect, we use a fiber with increased core size and reduced length, which allows us to reach a pulse energy of over 1 mJ in 88 ns long pulses. The drawbacks are that the core size increase leads to a transverse multimode output and in addition increases the amplified spontaneous emission (ASE) which limits energy extraction.

We report a narrow-linewidth (Δλ = 0.4 nm) optical pulsed MOPA (master oscillator - power amplifier) source emitting 0.41 mJ pulses (1.5 kW peak power) in the eye-safe range (λ = 1548 nm). Pulse duration and repetition rate were 90 ns and 5 kHz respectively.

We review the recent rapid progress in the area of high-power fibre lasers and amplifiers in 1.1 and 1.5 /spl mu/m spectral ranges. This progress is represented by a 610 W Yb-doped fibre laser, for example.

We calculate the modal power distribution of a randomly and linearly polarized (LP) multimode beam inside a cylindrical fiber core from knowledge of spatial-intensity profiles of a beam emitted from the fiber. We provide an exact analysis with rigorous proofs that forms the basis for our calculations. The beam from the fiber end is collimated by a spherical lens with a specific focal length. The original LP-mode basis is transformed by the spherical lens and forms another orthogonal basis that describes the free-space beam. By using this basis, we calculate the modal power distribution from the mutual-intensity profile. This is acquired by adopting a well-known mutual-intensity-profile-retrieving technique based on measurements of the intensity patterns several times after two orthogonal cylindrical lenses with varying separation. The feasibility of our decomposition algorithm is demonstrated with simulations.

High power pulsed fiber lasers and amplifiers based on Er or Er-Yb fibers have received much attention in recent years due to advantages such as compactness, efficiency, relative eye safety, high brightness, and compatibility with telecom components at 1550 nm. Applications such as lidar also benefit from a low weight. A seed source, followed by a cascade of erbium-doped fiber amplifiers, are an attractive means to this end, providing for a compact, reliable, and versatile system. So far, however, pulse energies achieved with such amplifier cascades have been significantly less than 1 mJ.Here, we report a MOPA (master oscillator-power amplifier) optical fiber source with a record pulse energy of 1.15 mJ at low repetition rates in a high-brightness beam (M2 = 1.6). Maximum average output power was 2.2 W. The wavelength of operation was 1562 nm and the repetition rate was 0.8-10 kHz. The pulse duration varied between 50 and 500 ns. Our fiber MOPA source consisted of an actively Q-switched erbium-ytterbium codoped fiber ring laser spliced to a high-power cladding-pumped multimode Er-Yb co-doped fiber amplifier. High-brightness operation (with suppression of unwanted modes) was obtained through spatial mode-selection. Additional results with different seed sources and at higher powers will be presented at the conference.

Passive Q-switching of fiber lasers with saturable absorbers have attracted attention because of simplicity and high efficiency. However, the number of known materials which can be used as a saturable absorber is relatively limited due to the features of fiber lasers. While liquefying gallium mirror, semiconductor structures (SESAM), as well as Co2+:ZnSe and Co2+:ZnS crystals are recent examples of saturable absorbers that have been used in Q-switched fiber lasers, any new material which can be used for this is still very interesting.Here we report, for the first time to our knowledge, a cladding-pumped passively Q-switched Er-Yb codoped fiber laser with Cr2+:ZnSe and Co2+:MgAl2O4 as saturable absorbers.The fiber laser configuration consists of a 5m circular double-clad Er-Yb codoped fiber and an external cavity. Pump light at 915nm was coupled into the fiber through a perpendicularly cleaved fiber end facet. This also serves as a 4% reflecting, outcoupling, cavity mirror. In the other end of the cavity a lens system and a high-reflection (1550 nm) mirror provided external feedback. The lens system had an intermediate focus, where the saturable absorber was located. The intermediate focus waist diameter was typically 20 µm. We used the same laser configuration for both the Cr2+:ZnSe and the Co2+:MgAl2O4 crystals. The maximum average output power for both crystals was 1.4 W, for 6.5 W of absorbed pump power. The maximum obtained pulse energy was 18 pJ (45W peak power) with Cr2+:ZnSe saturable absorber. Typical pulse duration was 370 - 700 ns. The repetition rate was varied between 20 and 85 kHz.The maximum pulse energy was 22 pJ (60W peak power) with Co2+:MgAl2O4 saturable absorber. The pulse duration was 370 - 600 ns. The repetition rate was varied between 15 and 65kHz.Further details and comparisons of fiber lasers passively Q-switched with Cr2+:ZnSe and Co2+:MgAl2O4 crystals will be presented.

A cladding pumped jacketed-air-clad ytterbium-doped fiber amplifier operating at 977 nm produced 4.3 W of single-mode output power with 300 mW of input power from a diode seed laser. The small-signal gain was 19 dB.

We demonstrate a high power erbium-ytterbium co-doped large-core fiber laser with narrow linewidth, an M2 value of 1.7 and a broad tuning range. The fiber was cladding-pumped by a diode stack emitting at 975 nm. The laser had a linewidth around 0.16 nm and was tuned from 1533 nm to 1566 nm by compression-tuning a fiber Bragg grating. Output powers in excess of 30 W were obtained over the entire laser tuning range which was limited by the low gain at wavelengths shorter than 1533 nm and by the grating fabrication wavelength at 1566 nm. The laser slope efficiency was ~30% and the threshold ~3.3 W. Our results underline the capability for efficient, broad-band, high-power operation of large-core Er-Yb doped fibers and demonstrate compatibility with telecom components like standard single-mode fibers and fiber Bragg gratings.

A continuous-wave (CW) master oscillator-power amplifier (MOPA) fiber source, tunable around 978 nm, was frequency-doubled to 488.7 nm. Both the laser and the amplifier were made with cladding-pumped jacketed air-clad Yb-doped fibers. The MOPA generated up to 2.7 W of power in an output beam with an M/sup 2/ value of 1.8. This was frequency-doubled in a periodically poled potassium titanyl phosphate crystal at room temperature, in a single-pass configuration. The generated blue light had a CW power of 18.1 mW, a nearly Gaussian spatial intensity profile, and an M/sup 2/ value of 1.7.

We will review recent progress on cladding-pumped fiber devices with output powers up to the kilowatt level and broad wavelength tunability in the 1 - 2 µm wavelength regime where silica fibers work well.

Over 1 kW of output power has now been reached with nearly diffraction-limited ytterbium-doped fiber lasers. Amplifiers can reach comparable powers, even with single-frequency beams. We review these and other recent results and discuss the possibilities for further progress.

An Er:Yb codoped fiber amplifier chain for the generation of pulses for coherent lidar applications at a wavelength near 1.5 microm is reported. The final 1.8-m-long power amplification stage had a 50-microm core diameter and yielded a 23-dB energy gain, resulting in 0.29-mJ, 100-ns pulses at a repetition rate of 4 kHz with no Brillouin scattering and an M2 of 2.1.