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The upcoming GAMMA-400 experiment will be implemented aboard the Russian astrophysical space observatory, which will be operating in a highly elliptical orbit over a period of 7 years to provide new data on gamma-ray emissions and cosmic-ray electron + positron fluxes, mainly from the galactic plane, the Galactic Center, and the Sun. The main observation mode will be a continuous point-source mode, with a duration of up to ~100 days. The GAMMA-400 gamma-ray telescope will study high-energy gamma-ray emissions of up to several TeV and cosmic-ray electrons + positrons up to 20 TeV. The GAMMA-400 telescope will have a high angular resolution, high energy and time resolutions, and a very good separation efficiency for separating gamma rays from the cosmic-ray background and the electrons + positrons from protons. A distinctive feature of the GAMMA-400 gamma-ray telescope is its wonderful angular resolution for energies of >30 GeV (0.01° for Eγ = 100 GeV), which exceeds the resolutions of space-based and ground-based gamma-ray telescopes by a factor of 5–10. GAMMA-400 studies can reveal gamma-ray emissions from dark matter particles' annihilation or decay, identify many unassociated, discrete sources, explore the extended sources' structures, and improve the cosmic-ray electron + positron spectra data for energies of >30 GeV. [ABSTRACT FROM AUTHOR]

The GAMMA-400 gamma-ray telescope is the successor of Soviet and Russian gamma-ray telescopes. GAMMA-400 is being developed for cosmophysical research in accordance with the Russian Federal Space Program 2016–2025. The GAMMA-400 experiment will be implemented aboard the Russian astrophysical space observatory in a highly elliptic orbit during 7 years to provide new data on gamma-ray emission mainly from the Galactic plane, Galactic Center, the Sun and cosmic-ray electron positron fluxes. The main mode of observations will be the continuous point-source mode with the duration of up to 100 days. The GAMMA-400 gamma-ray telescope will study high-energy gamma-ray emission up to several TeV and cosmic-ray electrons positrons up to 20 TeV. GAMMA-400 will have the never-achieved angular resolution, the high-energy and time resolutions, as well as very good separation efficiency of gamma rays from cosmic-ray background and of electrons positrons from protons. The distinctive features of GAMMA-400 are the excellent angular resolution of at GeV that exceeds resolutions of the space-based and ground-based gamma-ray telescopes by a factor of 5–10, as well as high-energy resolution of at GeV. GAMMA-400 studies can discover gamma-ray emission from annihilation or decay of dark matter particles, identify many unassociated discrete sources, explore the structure of extended sources, search for gamma-ray bursts and solar gamma-ray flares, improve the data on cosmic-ray electron positron spectra for energies of >50 GeV. [ABSTRACT FROM AUTHOR]

The space observatory GAMMA-400 is processed currently in accordance with the Federal Space Program of the Russian Federation for 2016–2025. The observatory includes a gamma-ray telescope for experimental studies of gamma rays in the energy range from ~20 MeV to ~1 TeV with high angular and energy resolution, as well as for research of electrons + positrons at energies above 100 GeV in both the main (top-down), and lateral apertures. At present time, there are experimental indications concerning the possibility of existing of spectrum break in electrons + positrons intensities about TeV energies. This point stimulates several speculations to explain such phenomena. In this paper we examined capabilities of GAMMA-400 telescope to explore this problem. The methods for electron detection in the energy range from 100 GeV up to 10 TeV from the lateral aperture of a gamma-ray telescope are presented. Also, the results of calculation for proton rejection factor and for electron acceptance are revealed. [ABSTRACT FROM AUTHOR]

The future space-based GAMMA-400 -ray telescope will operate onboard the Russian astrophysical observatory in a highly elliptic orbit during 7 years. Observing -ray sources from Galactic plane, -ray bursts, -ray diffuse emission, rays from the Sun, and rays from dark matter particles will be performed uninterruptedly for a long time ( 100 days) in point-source mode in contrast to scanning mode for Fermi-LAT and other space- and ground-based instruments. GAMMA-400 will measure rays in the energy range from 20 MeV to several TeV units, have the unprecedented angular ( at GeV) and energy ( at GeV) resolutions better than for Fermi-LAT, as well as ground-based -ray facilities, by a factor of 5–10, and perfectly separate rays from cosmic-ray background. [ABSTRACT FROM AUTHOR]

The GAMMA-400 gamma-ray telescope is planned for the launch at the end of 2026 on the Navigator service platform designed by Lavochkin Association on an elliptical orbit with following initial parameters: an apogee 300 000, a perigee 500 km, a rotation period 7 days and inclination of 51.4 . The apparatus is expected to operate for more than 5 years, reaching an unprecedented sensitivity for the search of dark matter signatures and the study of the unresolved and so far unidentified gamma-ray sources. The segmented anticoincidence counters surround the converter-tracker and calorimeter of the telescope with the purpose of vetoing to assure a clean track reconstruction and charged particle background suppression. The anticoincidence detector prototype based on long BC-408 scintillator with silicon photomultipliers readout was tested using 300-MeV positron beam of synchrotron C-25P "PAKHRA" of Lebedev Physical Institute. The measurement setup, design concepts for the prototype detector together with test results are discussed. [ABSTRACT FROM AUTHOR]

The space-based GAMMA-400 gamma-ray telescope will measure the fluxes of gamma rays in the energy range from ∼20 MeV to several TeV and cosmic-ray electrons and positrons in the energy range from several GeV to several TeV to investigate the origin of gamma-ray sources, sources and propagation of the Galactic cosmic rays and signatures of dark matter. The instrument consists of an anticoincidence system, a converter-tracker (thickness one radiation length, 1 X0), a time-of-flight system, an imaging calorimeter (2 X0) with tracker, a top shower scintillator detector, an electromagnetic calorimeter from CsI(Tl) crystals (16 X0) with four lateral scintillation detectors and a bottom shower scintillator detector. In this paper, the capability of the GAMMA-400 gamma-ray telescope for electron and positron measurements is analyzed. The bulk of cosmic rays are protons, whereas the contribution of the leptonic component to the total flux is ∼10−3 at high energy. The special methods for Monte Carlo simulations are proposed to distinguish electrons and positrons from proton background in the GAMMA-400 gamma-ray telescope. The contribution to the proton rejection from each detector system of the instrument is studied separately. The use of the combined information from all detectors allows us to reach a proton rejection of up to ∼1 × 104. [ABSTRACT FROM AUTHOR]

The GAMMA-400 (Gamma Astronomical Multifunctional Modular Apparatus) will be a new generation satellite gamma-observatory. The gamma-ray telescope GAMMA-400 consists of the anticoincidence system (top and lateral sections—ACtop and AClat), the converter-tracker (C), the time-of-flight system TOF (two sections S1 and S2), the position-sensitive and electromagnetic calorimeters (CC1 and CC2), the scintillation detectors of the calorimeter (S3 and S4) and lateral anticoincidence detectors of the calorimeter LD. Two apertures used for observation of transient events do not require the best angular resolution as for the gamma-ray bursts and solar flares from both upper and lateral directions. Additional aperture allows the particle registering from upper direction, which do not interact with converter-tracker and do not form a TOF signal. The lateral aperture allows registering of γ-quanta in perpendicular direction with respect to main axis of GAMMA-400 due to CC2, LD, S3, and S4. The thickness of CC2 in this direction is ∼44 X0 and this allows detection of gammas, electrons and positrons with energies up to 10 TeV. The results of calculation of the fractal dimension of temporal profiles of additional aperture prototype of GAMMA-400 during its calibration using secondary positron beam of the synchrotron C-25P "PAKHRA" of Lebedev Physical Institute confirm the absence of any correlation between the AC and CC1 characteristics and correspondence of additional aperture background to Poisson statistics or Erlang one with shape parameter up to 10. [ABSTRACT FROM AUTHOR]

The GAMMA-400 space project is one of the new generation of space observatories designed to search for signs of dark matter in the cosmic gamma emission, and to measure the characteristics of diffuse gamma-ray emission and gamma-rays from the Sun during periods of solar activity; gamma-ray bursts; extended and point gamma-ray sources; and electron, positron, and cosmic-ray nuclei fluxes with energies in the TeV ranges. The GAMMA-400 γ-ray telescope constitutes the core of the scientific instrumentation. The nature of the intended experiments imposes stringent requirements on the gamma telescope's system of trigger signal formation, now being developed using the state-of-the-art logic devices and fast data links. The design concept of the system is discussed, along with the chosen engineering solutions and some experimental results obtained during the operation of the system prototype using a positron beam with energies of 100–300 MeV from the PAKHRA S-25R synchrotron at the Lebedev Physical Institute. [ABSTRACT FROM AUTHOR]

The MONICA satellite-based experiment is described. In this experiment, fluxes of cosmic-ray ions from H to Ni are investigated near the Earth in the energy range of 10-300 MeV/nucleon. The main scientific objectives of the MONICA experiment are to measure the ion and isotope compositions and the energy spectra of solar cosmic rays for individual solar events and to study the evolution of these characteristics over time. The MONICA experiment will help to investigate the ion and isotope composition of the anomalous component of cosmic rays, galactic cosmic rays, and nuclear fluxes in the Earth’s radiation belt. Observations of ion fluxes will be carried out using the MONICA high-aperture multilayer semiconductor spectrometer-telescope installed on board a spacecraft with a low-Earth circular polar orbit at a height of approximately 600 km. This orbit will make it possible to perform the method for measuring the charge of ions with energies above 10 MeV/nucleon, which is based on the use of the Earth’s magnetic field as a particle- charge separator. The geometric factor of the instrument is 100 cm2 sr and the angular resolution is 1°. [ABSTRACT FROM AUTHOR]

The GAMMA-400 γ-ray telescope installed at the Russian space observatory is intended for precision measurements in the energy range of 20 MeV-1000 GeV of γ-ray emission (with the angular and energy resolutions several times better than that of current γ-ray telescopes) from discrete sources; measurement of the energy spectra of Galactic and extragalactic diffuse γ-ray emission; studies of γ-ray emission from the active Sun; and measurements of fluxes of γ-ray emission and electron-positron cosmicray component, which are probably associated with the annihilation or decay of dark-matter particles. [ABSTRACT FROM AUTHOR]

The future space-based γ-ray telescope GAMMA-400 will be installed on the Navigator platform of the Russian astrophysical observatory. A highly elliptical orbit will allow prolonged (~100 days) continuous observations of many regions of the celestial sphere for 7–10 years. GAMMA-400 will measure fluxes of γ‑ray emission in the energy range of ~20 MeV to several TeV and electrons + positrons to ~20 TeV. The γ-ray telescope will have excellent separation of γ-ray emissions against the background of cosmic rays and electrons + positrons from protons, along with unprecedented angular (~0.01° at Eγ = 100 GeV) and energy (~1% at Eγ = 100 GeV) resolutions 5–10 times better than for the Fermi-LAT and ground-based γ-ray telescopes. GAMMA-400 observations will provide fundamentally new data on discrete sources and spectra of γ-ray emissions and electrons + positrons. [ABSTRACT FROM AUTHOR]

An array of scintillation detectors of the MONICA Spectrometer, whis is aimed at investigating fluxes of cosmic-ray ions (from H to Ni) in the extraterrestrial space within the energy range from 10 to 300 MeV per nucleon, is considered. The basic goal of the MONICA experiment is the measurement of the ionic and isotopic composition of cosmic rays of the galactic and solar origin, as well as the measurement of their energy spectrum. This problem was intensely studied by numerous investigators [1-10]; nevertheless, a lot of questions remain unsolved up to now, in this field of science. The array of scintillation detectors plays the important role in achieving the goals of the MONICA experiment. The composition of the array, tuning procedure, and characteristics of scintillation detectors are discussed in detail. [ABSTRACT FROM AUTHOR]

The current status of the MONICA experiment to study fluxes of cosmic ray ions from H to Ni in the energy range of 10-300 MeV in the vicinity of the Earth is described. The main scientific objective of the MONICA experiment is to measure the ionic and isotope compositions and energy spectra of solar cosmic rays for individual solar events, and to study the time evolution of these characteristics. The MONICA experiment will also allow us to investigate the ionic and isotope compositions of the anomalous cosmic ray component, galactic cosmic rays, and fluxes of nuclei in the Earth's radiation belt. Ion fluxes will be observed using the MONICA large-aperture multilayer semiconductor spectrometer telescope on board a spacecraft in a circumterrestrial polar orbit with an altitude on the order of 600 km. This will enable us to measure the charges of ions with energies over 10 MeV/nucleon by using the Earth's magnetic field as a charge separator. The geometric factor of the instrument is 100 cm sr; its angular resolution is 1°. [ABSTRACT FROM AUTHOR]

We discuss the results of comparison and optimization of (Δ E − E) methods for identifying nuclei with the aid of a multilayer Si detector that will be used in the MONICA satellite-based experiment aimed at studying the nuclear component of cosmic rays from hydrogen to nickel in the energy range of 10–300 MeV/nucleon. The residual-range and Bethe-Bloch curve approximation methods are considered. Using the GEANT4 simulation, it is shown that the Bethe-Bloch curve approximation method not only ensures a better mass resolution (which is particularly important for identification of heavy nuclei), but also provides a means for identifying “drift” nuclei with satisfactory charge (<0.3) and energy (<3%) resolutions. The results can be used to prepare new experiments in which (Δ E − E) nuclear identification methods are expected to be employed. [ABSTRACT FROM AUTHOR]

We discuss the guidelines used in the design of the vessels of WWER-1000 (water-cooled water-moderated) nuclear reactors. The characteristic specific features of the structure of the reactor vessel are discussed, and the subsequent steps of improvement of its design aimed at the increase in its operating safety and designed service life up to 60 years are proposed. [ABSTRACT FROM AUTHOR]

The article discusses the ARINA satellite experiment in Russia which studied seismic effects in the high-energy particle fluxes in the magnetosphere of the Earth. The measurement of particle fluxes was conducted onboard the low-orbit Resurs-DK-1 spacecraft using a multi-layer scintillation detector. The study found that the detector demonstrated reliability for use in various space physics studies.

Results of calibration of the PAMELA instrument at the CERN facilities are discussed. In September, 2003, the calibration of the Neutron Detector together with the Calorimeter was performed with the CERN beams of electrons and protons with energies of 20 – 180 GeV. The implementation of the Neutron Detector increases a rejection factor of hadrons from electrons about ten times. The results of calibration are in agreement with calculations. [ABSTRACT FROM AUTHOR]

PAMELA is a satellite-borne experiment that will study the antiproton and positron fluxes in cosmic rays in a wide range of energy (from 80 MeV up to 190 GeV for antiprotons and from 50 MeV up to 270 GeV for positrons) and with high statistics, and that will measure the antihelium/helium ratio with a sensitivity of the order of 10-8. The detector will fly on-board a polar orbiting Resurs DK1 satellite, which will be launched into space by a Soyuz rocket in 2004 from Baikonur cosmodrome in Kazakhstan, for a 3-year-long mission. Particle identification and energy measurements are performed in the PAMELA apparatus using the following subdetectors: a magnetic spectrometer made up of a permanent magnet equipped with double-sided microstrip silicon detectors, an electromagnetic imaging calorimeter composed of layers of tungsten absorber and silicon detectors planes. a transition radiation detector made of straw tubes interleaved with carbon fiber radiators, a plastic scintillator time-of-flight and trigger system, a set of anticounter plastic scintillator detectors, and a neutron detector. The features of the detectors and the main results obtained in beam test sessions are presented. [ABSTRACT FROM AUTHOR]

Based on the available experimental data and the results of calculations carried out in this paper, cross sections are estimated for single-electron stripping of O[sup z+] (Z = 1-7) ions with energies in the range E = 0.5-200 MeV/u due to collisions with H, He, N, O, or Ar atoms. Analytical approximations of the cross sections are presented. [ABSTRACT FROM AUTHOR]

We described an approach suitable for obtaining an analytical expression for the energy of an antiphase boundary in an ordered alloy in the hard sphere model using pair interatomic interaction potentials. Depending on the orientation of the antiphase boundary, the crystal is subdivided into two-dimensional monatomic packings parallel to the defect, and its energy is determined by the sum of the energies of the two-dimensional packings. The results of the calculations for antiphase boundaries of different orientations are given in the form of matrix expressions for each of the considered superstructures. [ABSTRACT FROM AUTHOR]

The results from observing bursts of high-energy charged particle fluxes in near-Earth space, caused by local disturbances of the radiation belt and particles precipitating from it, in the ARINA (on board the RESURS-DKI satellite since 2006) and VSPLESK (on board the International Space Station since 2008) satellite experiments are presented. New features were revealed in the geographic distribution of particle bursts, indicating that most high-energy electron bursts are interrelated with thunderstorm and seismic activities, at that some bursts are observed in regions of tectonic faults. Results from observing high-energy electron precipitation from the radiation belt over Japan during the powerful seismic event that began on March 11, 2011, are analyzed. [ABSTRACT FROM AUTHOR]

New results are presented on the observations of bursts and variations in high-energy charged-particle fluxes in the near-Earth space by the ARINA instrument operated onboard the Resurs-DK1 satellite since 2006. [ABSTRACT FROM AUTHOR]