Персона:
Григоренко, Леонид Валентинович

Организационные подразделения

Организационная единица

Институт лазерных и плазменных технологий

Стратегическая цель Института ЛаПлаз – стать ведущей научной школой и ядром развития инноваций по лазерным, плазменным, радиационным и ускорительным технологиям, с уникальными образовательными программами, востребованными на российском и мировом рынке образовательных услуг.

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Григоренко

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Леонид Валентинович

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Теперь показываю 1 - 10 из 19

Только метаданные
Validity of Quasi-classical Approaches to True Three-Body Decays
(2020) Sukhareva, O. M.; Kostyleva, D. A.; Zhukov, M. V.; Grigorenko, L. V.; Григоренко, Леонид Валентинович
© Springer Nature Switzerland AG 2020.Within the hyperspherical harmonics (HH) method the three-body problem is reduced to a motion of one effective particle in a “strongly deformed” field, which is described in the coupled-channel formalism. This method is well suited to studies of so-called true three-body decays. The reduction of the hyperspherical equations set to a single-channel approximation provides the basis of standard quasi-classical (QC) expression for width evaluation. We demonstrate that by itself the quasi-classical approach is quite precise in application to typical three-body effective potentials. However, the reduction to a single channel leads to a significant overestimation of the width.
Только метаданные
Towards the Limits of Existence of Nuclear Structure: Observation and First Spectroscopy of the Isotope K-31 by Measuring Its Three-Proton Decay
(2019) Kostyleva, D.; Mukha, I.; Acosta, L.; Casarejos, E.; Grigorenko, L. V.; Григоренко, Леонид Валентинович
The most remote isotope from the proton dripline (by 4 atomic mass units) has been observed: K-31. It is unbound with respect to three-proton (3p) emission, and its decays have been detected in flight by measuring the trajectories of all decay products using microstrip detectors. The 3p emission processes have been studied by the means of angular correlations of S-28 + 3p and the respective decay vertices. The energies of the previously unknown ground and excited states of K-31 have been determined. This provides its 3p separation energy value S-3p of -4.6(2) MeV. Upper half-life limits of 10 ps of the observed K-31 states have been derived from distributions of the measured decay vertices.
Только метаданные
Detailed Study of External Correlations in the Low-Energy Spectrum of Beryllium-6
(2019) Chudoba, V.; Fomichev, A. S.; Bezbakh, A. A.; Egorova, I. A.; Grigorenko, L. V.; Григоренко, Леонид Валентинович
© 2019, Allerton Press, Inc.Abstract: Three-body continuum p-p-α for the charge exchange reaction 1H(6Li,6Be)n is studied in detail. The data are obtained with a high volume of statistics (approximately 4.7 million events), making it possible to analyze three-particle correlations. Detailed information about the structure of 6Ве and the reaction is obtained as a result.
Только метаданные
Pauli-principle Driven Correlations in Four-neutron Nuclear Decays
(2019) Sharov, P. G.; Ismailova, A. N.; Zhukov, M. V.; Grigorenko, L. V.; Григоренко, Леонид Валентинович
© 2019, Pleiades Publishing, Inc.Mechanism of simultaneous non-sequential four-neutron (4n) emission (or “true” 4n-decay) has been considered in phenomenological five-body approach. This approach is analogous to the model of the direct decay to the continuum often applied to 2n-and 2p-decays. It is demonstrated that 4n-decay fragments should have specific energy and angular correlations reflecting strong spatial correlations of “valence” nucleons orbiting in their 4n-precursors. Due to the Pauli exclusion principle, the valence neutrons are pushed to the symmetry-allowed configurations in the 4n-precursor structure, which causes a “Pauli focusing” effect. Prospects of the observation of the Pauli focusing have been considered for the 4n-precursors 7Hand 28 O. Fingerprints of their nuclear structure or/and decay dynamics are predicted.
Только метаданные
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.
Только метаданные
Scientific program of DERICA-prospective accelerator and storage ring facility for radioactive ion beam research
(2019) Grigorenko, L. V.; Sharkov, B. Y.; Fomichev, A. S.; Barabanov, A. L.; Barth, W.; Polozov, S. M.; Yaramyshev, S.; Григоренко, Леонид Валентинович; Полозов, Сергей Маркович
Studies of radioactive ions (RIs) are the most thriving field of low-energy nuclear physics. In this paper, the concept and the scientific agenda of the prospective accelerator and storage ring facility for RI beam (RIB) research are proposed for a large-scale international project based at the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research. The motivation for the new facility is discussed and its characteristics are briefly presented and shown to be comparable to those of advanced world centers, the so-called "RIB factories". In the project, the emphasis is made on studies with short-lived RIBs in storage rings. Aunique feature of the project is the possibility of studying electron-RI interactions in a collider experiment to determine the fundamental properties of nuclear matter, in particular, electromagnetic form factors of exotic nuclei.
Только метаданные
Beam Dynamics Simulation in the LINAC-100 Accelerator Driver for the DERICA Project
(2019) Fomichev, A. S.; Lozeeva, T. A.; Lozeev, Y. Y.; Polozov, S. M.; Samoshin, A. V.; Grigorenko, L. V.; Barth, W.; Yaramyshev, S.; Лозеева, Татьяна Андреевна; Лозеев, Юрий Юрьевич; Полозов, Сергей Маркович; Самошин, Александр Вячеславович; Григоренко, Леонид Валентинович
© 2019, Pleiades Publishing, Ltd.The results of uranium ion beam dynamics simulation in front-end and superconducting sections of the accelerator-driver LINAC-100 for the new rare isotope facility DERICA (JINR, Dubna) are presented. The optimum parameters are chosen for the buncher accelerator with radiofrequency quadrupole focusing (RFQ) for uranium ion beam acceleration from the ion source up to the energy of 570 keV/nucleon. LINAC-100 modular superconducting part layout for uranium beam acceleration from 3 to 100 MeV/nucleon is obtained. The energies for the stripper section installation are chosen.
Только метаданные
DERICA Project and Strategies of the Development of Low-Energy Nuclear Physics
(2021) Kropachev, G. N.; Kulevoy, T. V.; Meshkov, I. N.; Fomichev, A. S.; Grigorenko, L. V.; Polozov, S. M.; Sharkov, B. Y.; Григоренко, Леонид Валентинович; Полозов, Сергей Маркович; Шарков, Борис Юрьевич
© 2021, Pleiades Publishing, Ltd.Abstract: Possible strategies of the development of low-energy nuclear physics in Russian Federation on the basis of the DERICA (Dubna Electron–Rare Isotope Collider fAcility) project is examined. DERICA is a multiuser multipurpose facility for the production and study of radioactive isotopes (RI). In the research program of DERICA, emphasis is placed on studying RI in collector rings, but a stage-by-stage implementation of the program of DERICA would make it possible to address a wide range of fundamental problems at each stage of its development at the cutting-edge level. The ambitious goal of creating an electron–radioactive ion collider for studying basic properties of RI in electron–ion scattering is proposed for the final stage of development of DERICA.
Только метаданные
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
Mass measurements of As, Se, and Br nuclei, and their implication on the proton-neutron interaction strength toward the N=Z line
(2021) Mardor, I.; Andres, S. A. S.; Dickel, T.; Amanbayev, D.; Grigorenko, L. V.; Григоренко, Леонид Валентинович
©2021 American Physical Society.Mass measurements of the nuclides As69,Se70,71, and Br71, produced via fragmentation of a Xe124 primary beam at the Fragment Separator (FRS) at GSI, have been performed with the multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) of the FRS Ion Catcher with an unprecedented mass resolving power of almost 1000000. Such high resolving power is the only way to achieve accurate results and resolve overlapping peaks of short-lived exotic nuclei, whose total number of accumulated events is always limited. For the nuclide As69, this is the first direct mass measurement. A mass uncertainty of 22 keV was achieved with only ten events. For the nuclide Se70, a mass uncertainty of 2.6 keV was obtained, corresponding to a relative accuracy of dm/m=4.0×10-8, with less than 500 events. The masses of the nuclides Se71 and Br71 have been measured with an uncertainty of 23 and 16 keV, respectively. Our results for the nuclides Se70,71 and Br71 are in good agreement with the 2016 Atomic Mass Evaluation, and our result for the nuclide As69 resolves the discrepancy between the previous indirect measurements. We measured also the mass of the molecule N14N15Ar40 (A=69) with a relative accuracy of dm/m=1.7×10-8, the highest yet achieved with an MR-TOF-MS. Our results show that the measured restrengthening of the proton-neutron interaction (dVpn) for odd-odd nuclei along the N=Z line above Z=29 (recently extended to Z=37) is hardly evident at the N-Z=2 line, and not evident at the N-Z=4 line. Nevertheless, detailed structure of dVpn along the N-Z=2 and N-Z=4 lines, confirmed by our mass measurements, may provide a hint regarding the ongoing ˜500 keV discrepancy in the mass value of the nuclide Br70, which prevents including it in the world average of Ft value for superallowed 0+?0+ ß decays. The reported work sets the stage for mass measurements with the FRS Ion Catcher of nuclei at and beyond the N=Z line in the same region of the nuclear chart, including the nuclide Br70.