Персона:
Белогуров, Сергей Геннадьевич

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Научная группа

Организационные подразделения

Организационная единица

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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Белогуров

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Сергей Геннадьевич

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Теперь показываю 1 - 10 из 25

Только метаданные
Characterization of 30 Ge-76 enriched Broad Energy Ge detectors for GERDA Phase II
(2019) Agostini, M.; Bakalyarov, A. M.; Andreotti, E.; Balata, M.; Belogurov, S.; Белогуров, Сергей Геннадьевич
The GERmanium Detector Array (Gerda) is a low background experiment located at the Laboratori Nazionali del Gran Sasso in Italy, which searches for neutrinoless double-beta decay of 76Se+2e-. Gerda has been conceived in two phases. Phase II, which started in December 2015, features several novelties including 30 new Ge-76 enriched detectors. These were manufactured according to the Broad Energy Germanium (BEGe) detector design that has a better background discrimination capability and energy resolution compared to formerly widely-used types. Prior to their installation, the new BEGe detectors were mounted in vacuum cryostats and characterized in detail in the Hades underground laboratory in Belgium. This paper describes the properties and the overall performance of these detectors during operation in vacuum. The characterization campaign provided not only direct input for Gerda Phase II data collection and analyses, but also allowed to study detector phenomena, detector correlations as well as to test the accuracy of pulse shape simulation codes.
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The First Experiments with the New ACCULINNA-2 Fragment Separator
(2019) Fomichev, A. S.; Bezbakh, A. A.; Wolski, R.; Gazeeva, E. M.; Belogurov, S. G.; Grigorenko, L. V.; Белогуров, Сергей Геннадьевич; Григоренко, Леонид Валентинович
© 2019, Allerton Press, Inc.Abstract: Characteristics of a new separator of radioactive ion beams (RIBs) are described. It was recently commissioned at the Flerov Laboratory of Nuclear Reactions (FLNR JINR) and is in operation at the primary beam line of the U-400M heavy ion cyclotron providing RIBs in energy range of 10–50 MeV/nucleon. Preliminary results obtained in the first experiments performed with this separator in 2018 are presented. A medium-term program of scientific research is discussed.
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Resonant states in H 7: Experimental studies of the H 2 (He 8, He 3) reaction
(2021) Muzalevskii, I. A.; Bezbakh, A. A.; Nikolskii, E. Yu.; Chudoba, V.; Belogurov, S. G.; Grigorenko, L. V.; Белогуров, Сергей Геннадьевич; Григоренко, Леонид Валентинович
© 2021 American Physical Society.The extremely neutron-rich system H7 was studied in the direct H2(He8,He3)H7 transfer reaction with a 26 AMeV secondary He8 beam [Bezbakh et al., Phys. Rev. Lett. 124, 022502 (2020)PRLTAO0031-900710.1103/PhysRevLett.124.022502]. The missing mass spectrum and center-of-mass angular distributions of H7, as well as the momentum distribution of the H3 fragment in the H7 frame, were constructed. In addition, we carried out another experiment with the same beam but a modified setup, which was cross-checked by the study of the H2(Be10,He3)Li9 reaction. A solid experimental evidence is provided that two resonant states of H7 are located in its spectrum at 2.2(5) and 5.5(3)MeV relative to the H3+4n decay threshold. Also, there are indications that the resonant states at 7.5(3) and 11.0(3)MeV are present in the measured H7 spectrum. Based on the energy and angular distributions, obtained for the studied H2(He8,He3)H7 reaction, the weakly populated 2.2(5)-MeV peak is ascribed to the H7 ground state. It is highly plausible that the firmly ascertained 5.5(3)-MeV state is the 5/2+ member of the H7 excitation 5/2+-3/2+ doublet, built on the 2+ configuration of valence neutrons. The supposed 7.5-MeV state can be another member of this doublet, which could not be resolved in Bezbakh et al. [Phys. Rev. Lett. 124, 022502 (2020)PRLTAO0031-900710.1103/PhysRevLett.124.022502]. Consequently, the two doublet members appeared in the spectrum of H7 in the work mentioned above as a single broad 6.5-MeV peak.
Только метаданные
Calibration of the Gerda experiment
(2021) Agostini, M.; Araujo, G.; Bakalyarov, A. M.; Balata, M.; Belogurov, S.; Белогуров, Сергей Геннадьевич
© 2021, The Author(s).The GERmanium Detector Array (Gerda) collaboration searched for neutrinoless double-β decay in 76Ge with an array of about 40 high-purity isotopically-enriched germanium detectors. The experimental signature of the decay is a monoenergetic signal at Qββ= 2039.061 (7) keV in the measured summed energy spectrum of the two emitted electrons. Both the energy reconstruction and resolution of the germanium detectors are crucial to separate a potential signal from various backgrounds, such as neutrino-accompanied double-β decays allowed by the Standard Model. The energy resolution and stability were determined and monitored as a function of time using data from regular 228Th calibrations. In this work, we describe the calibration process and associated data analysis of the full Gerda dataset, tailored to preserve the excellent resolution of the individual germanium detectors when combining data over several years.
Только метаданные
Characterization of inverted coaxial 76 Ge detectors in GERDA for future double- β decay experiments
(2021) Agostini, M.; Araujo, G.; Bakalyarov, A. M.; Balata, M.; Belogurov, S.; Kornoukhov, V. N.; Белогуров, Сергей Геннадьевич; Корноухов, Василий Николаевич
© 2021, The Author(s).Neutrinoless double-β decay of 76Ge is searched for with germanium detectors where source and detector of the decay are identical. For the success of future experiments it is important to increase the mass of the detectors. We report here on the characterization and testing of five prototype detectors manufactured in inverted coaxial (IC) geometry from material enriched to 88% in 76Ge. IC detectors combine the large mass of the traditional semi-coaxial Ge detectors with the superior resolution and pulse shape discrimination power of point contact detectors which exhibited so far much lower mass. Their performance has been found to be satisfactory both when operated in vacuum cryostat and bare in liquid argon within the Gerda setup. The measured resolutions at the Q-value for double-β decay of 76Ge (Qββ = 2039 keV) are about 2.1 keV full width at half maximum in vacuum cryostat. After 18 months of operation within the ultra-low background environment of the GERmanium Detector Array (Gerda) experiment and an accumulated exposure of 8.5 kg· year, the background index after analysis cuts is measured to be 4.9-3.4+7.3×10-4counts/(keV·kg·year) around Qββ. This work confirms the feasibility of IC detectors for the next-generation experiment Legend.
Только метаданные
H 6 states studied in the H 2 (He 8, He 4) reaction and evidence of an extremely correlated character of the H 5 ground state
(2022) Nikolskii, E. Yu.; Muzalevskii, I. A.; Bezbakh, A. A.; Chudoba, V.; Belogurov, S. G.; Grigorenko, L. V.; Белогуров, Сергей Геннадьевич; Григоренко, Леонид Валентинович
© 2022 American Physical Society.The extremely neutron-rich system H6 was studied in the direct H2(He8,He4)H6 transfer reaction with a 26A MeV secondary He8 beam. The measured missing mass spectrum shows a broad bump at ≈4-8 MeV above the H3+3n decay threshold. This bump can be interpreted as a broad resonant state in H6 at 6.8(5) MeV. The population cross section of such a presumably p-wave state (or it may be few overlapping states) in the energy range from 4 to 8 MeV is dσ/dωc.m.≃190-80+40μb/sr in the angular range 5°<θc.m.<16°. The obtained missing mass spectrum is practically free of H6 events below 3.5 MeV (dσ/dωc.m. 5μb/sr in the same angular range). The steep rise of the H6 missing mass spectrum at ≈3 MeV allows us to derive the lower limit for the possible resonant-state energy in H6 to be 4.5(3) MeV. According to the paring energy estimates, such a 4.5(3) MeV resonance is a realistic candidate for the H6 ground state (g.s.). The obtained results confirm that the decay mechanism of the H7 g.s. (located at 2.2 MeV above the H3+4n threshold) is the "true"(or simultaneous) 4n emission. The resonance energy profiles and the momentum distributions of fragments of the sequential H6→H5(g.s.)+n→H3+3n decay were analyzed by the theoretically updated direct four-body-decay and sequential-emission mechanisms. The measured momentum distributions of the H3 fragments in the H6 rest frame indicate very strong "dineutron-type"correlations in the H5 ground state decay.
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Search for exotic physics in double-,Q decays with GERDA Phase II
(2022) Agostini, M.; Alexander, A.; Araujo, G.; Bakalyarov, A. M.; Belogurov, S.; Белогуров, Сергей Геннадьевич
A search for Beyond the Standard Model double-/3 decay modes of 76Ge has been performed with data collected during the Phase II of the GERmanium Detector Array (GERDA) experiment, located at the Laboratori Nazionali del Gran Sasso of INFN (Italy). Improved limits on the decays involving Majorons have been obtained, compared to previous experiments with 76Ge, with half-life values on the order of 1023 yr. For the first time with 76Ge, limits on Lorentz invariance violation effects in double-/3 decay have been obtained. The isotropic coefficient a(3) of , which embeds Lorentz violation in double-/3 decay, has been constrained at the order of 10-6 GeV. We also set the first experimental limits on the search for light exotic fermions in double-/3 decay, including sterile neutrinos.
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Searches for new physics below twice the electron mass with GERDA
(2024) Agostini, M.; Alexander, A.; Araujo, G.; Belogurov, S.; Kornoukhov, V. N.; Белогуров, Сергей Геннадьевич; Корноухов, Василий Николаевич
A search for full energy depositions from bosonic keV-scale dark matter candidates of masses between 65 and 1021 keV has been performed with data collected during Phase II of the GERmanium Detector Array (Gerda) experiment. Our analysis includes direct dark matter absorption as well as dark Compton scattering. With a total exposure of 105.5 kg years, no evidence for a signal above the background has been observed. The resulting exclusion limits deduced with either Bayesian or Frequentist statistics are the most stringent direct constraints in the major part of the 140-1021 keV mass range. As an example, at a mass of 150 keV the dimensionless coupling of dark photons and axion-like particles to electrons has been constrained to
Только метаданные
Pulse shape analysis in GERDA Phase II
(2022) Agostini, M.; Araujo, G.; Bakalyarov, A. M.; Balata, M.; Belogurov, S.; Белогуров, Сергей Геннадьевич
The GERmanium Detector Array (GERDA) collaboration searched for neutrinoless double-beta decay in Ge-76 using isotopically enriched high purity germanium detectors at the Laboratori Nazionali del Gran Sasso of INFN. After Phase I (2011-2013), the experiment benefited from several upgrades, including an additional active veto based on LAr instrumentation and a significant increase of mass by point-contact germanium detectors that improved the halflife sensitivity of Phase II (2015-2019) by an order of magnitude. At the core of the background mitigation strategy, the analysis of the time profile of individual pulses provides a powerful topological discrimination of signal-like and background-like events. Data from regular Th-228 calibrations and physics data were both considered in the evaluation of the pulse shape discrimination performance. In this work, we describe the various methods applied to the data collected in GERDA Phase II corresponding to an exposure of 103.7 kg year. These methods suppress the background by a factor of about 5 in the region of interest around Q(beta beta) = 2039 keV, while preserving (81 +/- 3)% of the signal. In addition, an exhaustive list of parameters is provided which were used in the final data analysis.
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Final Results of GERDA on the Search for Neutrinoless Double-beta Decay
(2020) Agostini, M.; Araujo, G. R.; Bakalyarov, A. M.; Balata, M.; Belogurov, S.; Белогуров, Сергей Геннадьевич
The GERmanium Detector Array (GERDA) experiment searched for the lepton-number-violating neutrinoless double-beta (0 nu beta beta) decay of Ge-76, whose discovery would have far-reaching implications in cosmology and particle physics. By operating bare germanium diodes, enriched in Ge-76, in an active liquid argon shield, GERDA achieved an unprecedently low background index of 5.2 x 10(-4) counts/(keV kg yr) in the signal region and met the design goal to collect an exposure of 100 kg yr in a background-free regime. When combined with the result of Phase I, no signal is observed after 127.2 kg yr of total exposure. A limit on the half-life of 0 nu beta beta decay in Ge-76 is set at T-1/2 > 1.8 x 10(26) yr at 90% C.L., which coincides with the sensitivity assuming no signal.