Персона: Грачев, Виктор Михайлович
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Институт ядерной физики и технологий
Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.
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Виктор Михайлович
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- ПубликацияТолько метаданныеAnomaly of the Charge Spectrum of Galactic Cosmic Ray Nuclei in Olivines as Evidence of Meteorite Radiation History(2020) Alexandrov, A. B.; Bagulya, A. V.; Volkov, A. E.; Gippius, A. A.; Grachev, V. M.; Polukhina, N. G.; Грачев, Виктор Михайлович; Полухина, Наталья Геннадьевна© 2020, Allerton Press, Inc.Abstract: A new additional aspect of the analysis of the data of the OLYMPIA experiment on the search for nuclei of heavy cosmic ray components in olivine crystals from stony—iron meteorites is presented. Two groups of crystals with different charge spectra of recorded nuclei are detected. Possible causes of this phenomenon and its effect on the final spectrum are discussed.
- ПубликацияТолько метаданныеStudy of the Pallasite Radiation History by Track Analysis(2019) Alexeev, V. A.; Bagulya, A. V.; Volkov, A. E.; Gippius, A. A.; Grachev, V. M.; Polukhina, N. G.; Грачев, Виктор Михайлович; Полухина, Наталья ГеннадьевнаThis work was performed within the OLYMPIA experiment on the study of tracks of heavy and superheavy cosmic ray nuclei in olivine crystals from Marjalahti and Eagle Station pallasites. Depth distributions of the track formation rate for heavy cosmic ray nuclei in olivine crystals from pallasites of different pre-atmospheric sizes were obtained. The dependences obtained were used to analyze the data on the track density in olivine crystals from the Marjalahti pallasite. In three crystals, the track distribution with a high density gradient was detected, which indicates a complicated radiation history of the meteorite.
- ПубликацияТолько метаданныеMuonography of Large Natural and Industrial Objects(2019) Abiev, A. K.; Bagulya, A. V.; Chernyavsky, M. M.; Dimitrienko, A. A.; Grachev, V. M.; Polukhina, N. G.; Грачев, Виктор Михайлович; Полухина, Наталья Геннадьевна© 2019, Pleiades Publishing, Ltd.Cosmic ray muonography is a novel technique for imaging of the internal structures of large natural and industrial objects. It exploits the capability of high energy muons from cosmic rays to penetrate large thicknesses of large subjects to be studied, in order to obtain a density map. It uses muon flux attenuation and absorption in materials of investigated objects. Nuclear emulsions are tracking detectors well suited to be employed in muonography for investigations of inner structure of large objects up to kilometers size, since emulsions have firstly an excellent angular resolution, they are compact and robust, do not require power supply. The muonography methods are applied to study one of UNESCO world heritage objects, the unusual building in the Naryn-Kala citadel hidden underground. The use of nuclear emulsions as probing radiation detectors provides for a uniquely high resolution capacity of recording instrumentation combined with the potential of modern image analysis methods giving 3D reconstruction of the internal structures of the investigated object.
- ПубликацияТолько метаданныеDetermination of Charges of Superheavy Nuclei in Finding them in Nature(2019) Aleksandrov, A. B.; Alekseev, V. A.; Bagulya, A. V.; Dashkina, A. B.; Grachev, V. M.; Polukhina, N. G.; Грачев, Виктор Михайлович; Полухина, Наталья Геннадьевна© 2019, Allerton Press, Inc.The results of the search for tracks of heavy and superheavy nuclei of galactic cosmic rays in the charge range Z = 26 − 129, identified in olivine crystals from Maryalahti and Eagle Station meteorites are presented. The database including characteristics of 21743 tracks, obtained in the OLIMPIA experiment, is currently the largest one within the charge range under study. It includes three tracks of superheavy nuclei with charge 119−6 +10 and a minimum lifetime estimated as several tens of years, which can be considered as a direct experimental validation of the existence of natural superheavy nuclei from the “stability island”.
- ПубликацияТолько метаданныеSensitivity of the SHiP experiment to light dark matter(2021) Ahdida, C.; Akmete, A.; Albanese, R.; Alexandrov, A.; Atkin, E.; Dmitrenko, V.; Etenko, A.; Filippov, K.; Grachev, V.; Kudenko, Y.; Novikov, A.; Polukhina, N.; Samsonov, V.; Shustov, A.; Skorokhvatov, M.; Smirnov, S.; Teterin, P.; Ulin, S.; Uteshev, Z.; Vlasik, K.; Аткин, Эдуард Викторович; Дмитренко, Валерий Васильевич; Этенко, Александр Владимирович; Грачев, Виктор Михайлович; Куденко, Юрий Григорьевич; Полухина, Наталья Геннадьевна; Шустов, Александр Евгеньевич; Скорохватов, Михаил Дмитриевич; Смирнов, Сергей Юрьевич; Тетерин, Пётр Евгеньевич; Улин, Сергей Евгеньевич; Утешев, Зияэтдин Мухамедович; Власик, Константин Федорович© 2021, The Author(s).Dark matter is a well-established theoretical addition to the Standard Model supported by many observations in modern astrophysics and cosmology. In this context, the existence of weakly interacting massive particles represents an appealing solution to the observed thermal relic in the Universe. Indeed, a large experimental campaign is ongoing for the detection of such particles in the sub-GeV mass range. Adopting the benchmark scenario for light dark matter particles produced in the decay of a dark photon, with αD = 0.1 and mA′ = 3mχ, we study the potential of the SHiP experiment to detect such elusive particles through its Scattering and Neutrino detector (SND). In its 5-years run, corresponding to 2 · 1020 protons on target from the CERN SPS, we find that SHiP will improve the current limits in the mass range for the dark matter from about 1 MeV to 300 MeV. In particular, we show that SHiP will probe the thermal target for Majorana candidates in most of this mass window and even reach the Pseudo-Dirac thermal relic. [Figure not available: see fulltext.]
- ПубликацияТолько метаданныеHistory of heavy r-process elements in galactic cosmic rays from nuclei tracks in meteorite olivine(2022) Alexandrov, A.; Babaev, P.; Bagulya, A.; Chernyavsky, M.; Gippius, A.; Gorbunov, S.; Grachev, V.; Kalinina, G.; Konovalova, N.; Okateva, N.; Polukhina, N.; Грачев, Виктор Михайлович; Полухина, Наталья ГеннадьевнаThe OLIMPIYA project studies tracks of heavy nuclei from Galactic cosmic rays (GCR) in olivine crystals from two meteorites-pallasites of different cosmic-ray exposure ages. The updated data presented is used to analyze the history of local variations in the GCR flux over the past ∼200 Myr. The analysis demonstrates the difference in the abundances of heavy nuclei registered in the meteorites and satellite detectors, as well as in the meteorites themselves. This difference may indicate the influence of at least two rare cosmic sources of r-element nucleosynthesis on GCR fluxes in the vicinity of the Solar System. Two possible sources, namely Supernovae (SN) and asymptotic giant branch stars (AGB) events versus the neutron star mergers or neutron star - black hole mergers (NSM) events, are compared in terms of the yield of r-elements. © 2022 COSPAR
- ПубликацияТолько метаданныеFast simulation of muons produced at the SHiP experiment using Generative Adversarial Networks(2019) Ahdida, C.; Albanese, R. M.; Alexandrov, A.; Anokhina, A.; Atkin, E.; Dmitrenko, V.; Etenko, A.; Filippov, K.; Gavrilov, G.; Grachev, V.; Kudenko, Y.; Novikov, A.; Polukhina, N.; Samsonov, V.; Shustov, A.; Skorokhvatov, M.; Smirnov, S.; Teterin, P.; Ulin, S.; Uteshev, Z.; Vlasik, K.; Аткин, Эдуард Викторович; Дмитренко, Валерий Васильевич; Этенко, Александр Владимирович; Грачев, Виктор Михайлович; Куденко, Юрий Григорьевич; Полухина, Наталья Геннадьевна; Шустов, Александр Евгеньевич; Скорохватов, Михаил Дмитриевич; Смирнов, Сергей Юрьевич; Тетерин, Пётр Евгеньевич; Улин, Сергей Евгеньевич; Утешев, Зияэтдин Мухамедович; Власик, Константин Федорович© 2019 CERN.This paper presents a fast approach to simulating muons produced in interactions of the SPS proton beams with the target of the SHiP experiment. The SHiP experiment will be able to search for new long-lived particles produced in a 400 GeV/c SPS proton beam dump and which travel distances between fifty metres and tens of kilometers. The SHiP detector needs to operate under ultra-low background conditions and requires large simulated samples of muon induced background processes. Through the use of Generative Adversarial Networks it is possible to emulate the simulation of the interaction of 400 GeV/c proton beams with the SHiP target, an otherwise computationally intensive process. For the simulation requirements of the SHiP experiment, generative networks are capable of approximating the full simulation of the dense fixed target, offering a speed increase by a factor of (106). To evaluate the performance of such an approach, comparisons of the distributions of reconstructed muon momenta in SHiP's spectrometer between samples using the full simulation and samples produced through generative models are presented. The methods discussed in this paper can be generalised and applied to modelling any non-discrete multi-dimensional distribution.
- ПубликацияТолько метаданныеInsight into History of GCR Heavy Nuclei Fluxes by Their Tracks in Meteorites(2022) Alexandrov, A. B.; Bagulya, A. V.; Babaev, P. A.; Chernyavsky, M. M.; Gippius, A. A.; Gorbunov, S. A.; Grachev, V. M.; Polukhina, N. G.; Грачев, Виктор Михайлович; Полухина, Наталья ГеннадьевнаAbstract: The OLIMPIYA project investigates tracks of galactic cosmic rays (GCR) in olivine crystals from two meteorites-pallasites of different exposure ages. Extended statistics (up to 21 743 processed tracks) enabled to reveal a difference between the charge spectra of heaviest nuclei registered in these pallasites versus those from detectors mounted on near-Earth orbit satellites, as well as a difference between the GCR spectra registered in the meteorites themselves. Comparison of the r-element abundances in these spectra points that GCR fluxes from at least two rare cosmic nucleosynthesis events with enhanced production of these elements reached the Solar System during the exposition age of the older meteorite. Correlations of the experimental results with parameters of supernovae, asymptotic giant branches stars and neutron star mergers (NSM) are also discussed. © 2022, Pleiades Publishing, Ltd.
- ПубликацияТолько метаданныеThe SHiP experiment at the proposed CERN SPS Beam Dump Facility(2022) Ahdida, C.; Akmete, A.; Albanese, R.; Alt, J.; Atkin, E.; Dmitrenko, V.; Etenko, A.; Fillipov, K.; Grachev, V.; Kudenko, Y.; Polukhina, N.; Samsonov, V.; Shustov, A.; Skorokhvatov, M.; Smirnov, S.; Teterin, P.; Ulin, S.; Uteshev, Z.; Vlasik, K.; Аткин, Эдуард Викторович; Дмитренко, Валерий Васильевич; Этенко, Александр Владимирович; Грачев, Виктор Михайлович; Куденко, Юрий Григорьевич; Полухина, Наталья Геннадьевна; Шустов, Александр Евгеньевич; Скорохватов, Михаил Дмитриевич; Смирнов, Сергей Юрьевич; Тетерин, Пётр Евгеньевич; Улин, Сергей Евгеньевич; Утешев, Зияэтдин Мухамедович; Власик, Константин Федорович© 2022, The Author(s).The Search for Hidden Particles (SHiP) Collaboration has proposed a general-purpose experimental facility operating in beam-dump mode at the CERN SPS accelerator to search for light, feebly interacting particles. In the baseline configuration, the SHiP experiment incorporates two complementary detectors. The upstream detector is designed for recoil signatures of light dark matter (LDM) scattering and for neutrino physics, in particular with tau neutrinos. It consists of a spectrometer magnet housing a layered detector system with high-density LDM/neutrino target plates, emulsion-film technology and electronic high-precision tracking. The total detector target mass amounts to about eight tonnes. The downstream detector system aims at measuring visible decays of feebly interacting particles to both fully reconstructed final states and to partially reconstructed final states with neutrinos, in a nearly background-free environment. The detector consists of a 50m long decay volume under vacuum followed by a spectrometer and particle identification system with a rectangular acceptance of 5 m in width and 10 m in height. Using the high-intensity beam of 400GeV protons, the experiment aims at profiting from the 4 × 10 19 protons per year that are currently unexploited at the SPS, over a period of 5–10 years. This allows probing dark photons, dark scalars and pseudo-scalars, and heavy neutral leptons with GeV-scale masses in the direct searches at sensitivities that largely exceed those of existing and projected experiments. The sensitivity to light dark matter through scattering reaches well below the dark matter relic density limits in the range from a few MeV/c2 up to 100 MeV-scale masses, and it will be possible to study tau neutrino interactions with unprecedented statistics. This paper describes the SHiP experiment baseline setup and the detector systems, together with performance results from prototypes in test beams, as it was prepared for the 2020 Update of the European Strategy for Particle Physics. The expected detector performance from simulation is summarised at the end.
- ПубликацияТолько метаданныеTrack reconstruction and matching between emulsion and silicon pixel detectors for the SHiP-charm experiment(2022) Ahdida, C.; Akmete, A.; Albanese, R.; Alt, J.; Atkin, E.; Dmitrenko, V.; Etenko, A.; Fillipov, K.; Grachev, V.; Kudenko, Y.; Polukhina, N.; Samsonov, V.; Shustov, A.; Skorokhvatov, M.; Smirnov, S.; Teterin, P.; Ulin, S.; Uteshev, Z.; Vlasik, K.; Аткин, Эдуард Викторович; Дмитренко, Валерий Васильевич; Этенко, Александр Владимирович; Грачев, Виктор Михайлович; Куденко, Юрий Григорьевич; Полухина, Наталья Геннадьевна; Шустов, Александр Евгеньевич; Скорохватов, Михаил Дмитриевич; Смирнов, Сергей Юрьевич; Тетерин, Пётр Евгеньевич; Улин, Сергей Евгеньевич; Утешев, Зияэтдин Мухамедович; Власик, Константин Федорович© 2022 CERN.In July 2018 an optimization run for the proposed charm cross section measurement for SHiP was performed at the CERN SPS. A heavy, moving target instrumented with nuclear emulsion films followed by a silicon pixel tracker was installed in front of the Goliath magnet at the H4 proton beam-line. Behind the magnet, scintillating-fibre, drift-tube and RPC detectors were placed. The purpose of this run was to validate the measurement's feasibility, to develop the required analysis tools and fine-tune the detector layout. In this paper, we present the track reconstruction in the pixel tracker and the track matching with the moving emulsion detector. The pixel detector performed as expected and it is shown that, after proper alignment, a vertex matching rate of 87% is achieved.