| 1. |
- Aad, G, et al.
(author)
-
- 2015
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swepub:Mat__t
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| 2. |
- Reifarth, R., et al.
(author)
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Nuclear astrophysics with radioactive ions at FAIR
- 2016
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In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 665:1
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Conference paper (peer-reviewed)abstract
- The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process beta-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.
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| 3. |
- Antonov, A. N., et al.
(author)
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The electron-ion scattering experiment ELISe at the International Facility for Antiproton and Ion Research (FAIR)-A conceptual design study
- 2011
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In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002 .- 0167-5087. ; 637:1, s. 60-76
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Journal article (peer-reviewed)abstract
- The electron-ion scattering experiment ELISe is part of the installations envisaged at the new experimental storage ring at the International Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany. It offers an unique opportunity to use electrons as probe in investigations of the structure of exotic nuclei. The conceptual design and the scientific challenges of ELISe are presented. (C) 2011 Elsevier B.V. All rights reserved.
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| 4. |
- Grigorenko, L, et al.
(author)
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Scientific program of DERICA-prospective accelerator and storage ring facility for radioactive ion beam research
- 2019
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In: Physics-Uspekhi. - 1468-4780 .- 1063-7869. ; 62:7, s. 675-690
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Journal article (peer-reviewed)abstract
- 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. A unique 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.
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| 5. |
- Fomichev, A. S., et al.
(author)
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Recent results related to excited states of 6Be and 10He
- 2012
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In: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 38, s. Art. no. 15002-
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Conference paper (peer-reviewed)abstract
- The 1H(6Li,6Be)n charge-exchange reaction and the 3H(8He, p)10He two-neutron transfer reaction were recently carried out at the ACCULINNA fragment separator (FLNR, Dubna) to populate the ground and excited states of 6Be and 10He nuclei, respectively. The 6Be ET spectrum (ET is the 6Be energy above its 4He+p+p decay threshold) was obtained with high statistics and described by the well-known 0+ ground state of 6Be at ET = 1.37 MeV, the 2+ state at ET = 3.05 MeV and a broad structure extending from 4 to 16 MeV which could be interpreted as the isovector soft dipole mode associated with the 6Li ground state. In the 10He case the 0+ ground state was found at about 2.1(2) MeV (T ∼ 2 MeV) above the 8He+n+n breakup threshold. Angular correlations observed for 10He decay products show prominent interference patterns allowing to draw conclusions about the structure of low-energy excited states: 1- (E T ∼ 5 MeV) and 2+ (ET > 6 MeV).
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| 6. |
- Chudoba, V., et al.
(author)
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Three-body correlations in direct reactions: Example of Be 6 populated in the (p,n) reaction
- 2018
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In: Physical Review C. - 2469-9993 .- 2469-9985. ; 98:5
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Journal article (peer-reviewed)abstract
- The Be6 continuum states were populated in the charge-exchange reaction H1(Li6,Be6)n collecting very high statistics data (∼5×106 events) on the three-body α+p+p correlations. The Be6 excitation energy region below ∼3MeV is considered, where the data are dominated by contributions from the 0+ and 2+ states. It is demonstrated how the high-statistics few-body correlation data can be used to extract detailed information on the reaction mechanism. Such a derivation is based on the fact that highly spin-aligned states are typically populated in the direct reactions.
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| 7. |
- Fomichev, A. S., et al.
(author)
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Isovector soft dipole mode in Be-6
- 2012
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 708:1-2, s. 6-13
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Journal article (peer-reviewed)abstract
- By using the H-1(Li-6,Be-6)n charge-exchange reaction, population of continuum states in Be-6 was observed up to E-T = 16 MeV, E-T being the Be-6 energy above its three-body decay threshold. In kinematically complete measurements performed by detecting alpha + p + p coincidences, an E-T spectrum of high statistics was obtained, containing approximately similar to 5 x 10(6) events. The spectrum provides detailed correlation information about the well-known 0(+) ground state of Be-6 at E-T = 1.37 MeV and its 2(+) state at E-T = 3.05 MeV. Moreover, a broad structure extending from 4 to 16 MeV was observed. It contains negative parity states populated by Delta L = 1 angular momentum transfer without other significant contributions. This structure can be interpreted as a novel phenomenon, i.e. the isovector soft dipole mode associated with the Li-6 ground state. The population of this mode in the charge-exchange reaction is a dominant phenomenon for this reaction, being responsible for about 60% of the cross-section obtained in the measured energy range.
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| 8. |
- Fomichev, A. S., et al.
(author)
-
Long range plan with radioactive beams at Dubna
- 2010
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In: 3rd International Conference on Current Problems in Nuclear Physics and Atomic Energy, NPAE 2010; Kyiv; Ukraine; 7 June 2010 through 12 June 2010. ; , s. 64-69
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Conference paper (peer-reviewed)abstract
- A program for upgrade of existing radioactive ion beams facilities at Flerov Laboratory of Nuclear Reactions, JINR Dubna is presented. A project of a new in-flight fragment separator ACCULINNA-2 is proposed. It is expected the new instrument will be more universal and powerful than the existing nowadays. The beam intensity should be increased by factor 10-15, its optical quality greatly improved and the range of the accessible secondary radioactive beams broadened up to Z∼20. Main ion-optical characteristics, operating principles and a tentative plan for the project realization are included. An extensive research program based on local experiments made so far and international proposals for these equipments is discussed.
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| 9. |
- Fomichev, A. S., et al.
(author)
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Status of the ACCULINNA-2 project at FLNR
- 2012
-
In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 337:1, s. Art. no. 012025-
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Conference paper (peer-reviewed)abstract
- The project of a new and more powerful in-flight fragment separator ACCULINNA-2 at U-400M cyclotron in FLNR, JINR planned to build in addition to the existing separator ACCULINNA is presented. The new separator will provide high intensity RIBs in the lowest energy range (5÷50 MeV/nucleon) which is attainable for in-flight separators. The possibilities for the astrophysics studies at the proposed device are presented. ACCULINNA-2 separator is planned to be constructed in the years 2010-2015. The current status of the project is reported.
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| 10. |
- Fomichev, A. S., et al.
(author)
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The Suggested New Fragment Separator ACCULINNA-2
- 2010
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In: Acta Physica Polonica, Series B.. - 1509-5770 .- 0587-4254. ; 41:2, s. 475-480
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Journal article (peer-reviewed)abstract
- We present new project of fragment separator ACCULINNA-2 that is being planned to be constructed in Flerov Laboratory of Nuclear Reaction, JINR. The ACCULINNA-2 facility is not, intended to compete with the, new large in-flight RIB facilities. It, should complement the existing/constructed facilities in certain fields. Namely, ACCULINNA-2 should provide high intensity RIBs in the lowest energy range attainable for in-flight separators.
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| 11. |
- Krupko, S. A., et al.
(author)
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Fragment separator ACCULINNA-2
- 2010
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In: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. - 9780735407688 ; 1224, s. 516-521
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Conference paper (other academic/artistic)
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| 12. |
- Krupko, S. A., et al.
(author)
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The status of new fragment separator ACCULINNA-2 project and the first day experiments
- 2014
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In: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 66
-
Conference paper (peer-reviewed)abstract
- The new facility fragment separator ACCULINNA-2 will be put into operation at the beginning of 2015 in FLNR JINR. The new separator is destined to add considerably to the studies of drip-line nuclei performed with the use of variety of direct reactions known to be distinctive to the 15 - 50 MeV/amu exotic secondary RIBs. Intense beams provided by the U-400M cyclotron will ensure the achievement of this objective. In addition to the RIB separation accomplished by means of the dipole-wedge-dipole selection, the addition of a zero-degree dipole magnet setup is foreseen. A long (13 m) straight section will provide precise time-of-flight measurements. © Owned by the authors, published by EDP Sciences, 2014.
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| 13. |
- Chudoba, V., et al.
(author)
-
Detailed Study of External Correlations in the Low-Energy Spectrum of Beryllium-6
- 2019
-
In: Bulletin of the Russian Academy of Sciences: Physics. - 1062-8738 .- 1934-9432. ; 83:4, s. 392-398
-
Journal article (peer-reviewed)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.
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| 14. |
- Sørensen, Lasse K., et al.
(author)
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Thermal degradation of optical resonances in plasmonic nanoparticles
- 2022
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In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 14:2, s. 433-447
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Journal article (peer-reviewed)abstract
- The dependence of plasmon resonance excitations in ultrafine (3-7 nm) gold nanoparticles on heating and melting is investigated. An integrated approach is adopted, where molecular dynamics simulations of the spatial and temporal development of the atoms constituting the nanoparticles generate trajectories out of which system conformations are sampled and extracted for calculations of plasmonic excitation cross sections which then are averaged over the sample configurations for the final result. The calculations of the plasmonic excitations, which take into account the temperature- and size-dependent relaxation of the plasmons, are carried out with a newly developed Extended Discrete Interaction Model (Ex-DIM) and complemented by multilayered Mie theory. The integrated approach clearly demonstrates the conditions for suppression of the plasmons starting at temperatures well below the melting point. We have found a strong inhomogeneous dependence of the atom mobility in the particle crystal lattice increasing from the center to its surface upon the temperature growth. The plasmon resonance suppression is associated with an increase of the mobility and in the amplitude of phonon vibrations of the lattice atoms accompanied by electron-phonon scattering. This leads to an increase in the relaxation constant impeding the plasmon excitation as the major source of the suppression, while the direct contribution from the increase in the lattice constant and its chaotization at melting is found to be minor. Experimental verification of the suppression of surface plasmon resonance is demonstrated for gold nanoparticles on a quartz substrate heated up to the melting temperature and above.
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| 15. |
- Ershov, A. E., et al.
(author)
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Thermal limiting effects in optical plasmonic waveguides
- 2017
-
In: Journal of Quantitative Spectroscopy and Radiative Transfer. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0022-4073 .- 1879-1352. ; 191, s. 1-6
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Journal article (peer-reviewed)abstract
- We have studied thermal effects occurring during excitation of optical plasmonic waveguide (OPW) in the form of linear chain of spherical Ag nanoparticles by pulsed laser radiation. It was shown that heating and subsequent melting of the first irradiated particle in a chain can significantly deteriorate the transmission efficiency of OPW that is the crucial and limiting factor and continuous operation of OPW requires cooling devices. This effect is caused by suppression of particle's surface plasmon resonance due to reaching the melting point temperature. We have determined optimal excitation parameters which do not significantly affect the transmission efficiency of OPW.
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| 16. |
- Gerasimov, V. S., et al.
(author)
-
Suppression of surface plasmon resonance in Au nanoparticles upon transition to the liquid state
- 2016
-
In: Optics Express. - : OPTICAL SOC AMER. - 1094-4087. ; 24:23, s. 26851-26856
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Journal article (peer-reviewed)abstract
- Significant suppression of resonant properties of single gold nanoparticles at the surface plasmon frequency during heating and subsequent transition to the liquid state has been demonstrated experimentally and explained for the first time. The results for plasmonic absorption of the nanoparticles have been analyzed by means of Mie theory using experimental values of the optical constants for the liquid and solid metal. The good qualitative agreement between calculated and experimental spectra support the idea that the process of melting is accompanied by an abrupt increase of the relaxation constants, which depends, beside electron-phonon coupling, on electron scattering at a rising number of lattice defects in a particle upon growth of its temperature, and subsequent melting as a major cause for the observed plasmonic suppression. It is emphasized that observed effect is fully reversible and may underlie nonlinear optical responses of nanocolloids and composite materials containing plasmonic nanoparticles and their aggregates in conditions of local heating and in general, manifest itself in a wide range of plasmonics phenomena associated with strong heating of nanoparticles.
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| 17. |
- Gerasimov, V. S., et al.
(author)
-
Thermal effects in systems of colloidal plasmonic nanoparticles in high-intensity pulsed laser fields [Invited]
- 2017
-
In: Optical Materials Express. - : OSA - The Optical Society. - 2159-3930 .- 2159-3930. ; 7:2, s. 555-568
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Journal article (peer-reviewed)abstract
- We have studied light induced processes in nanocolloids and composite materials containing ordered and disordered aggregates of plasmonic nanoparticles accompanied by their strong heating. A universal comprehensive physical model that combines mechanical, electrodynamical, and thermal interactions at nanoscale has been developed as a tool for investigations. This model was used to gain deep insight on phenomena that take place in nanoparticle aggregates under high-intensity pulsed laser radiation resulting in the suppression of nanoparticle resonant properties. Verification of the model was carried out with single colloidal Au and Ag nanoparticles and their aggregates.
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| 18. |
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| 19. |
- Sørensen, Lasse K., et al.
(author)
-
Medium dependent optical response in ultra-fine plasmonic nanoparticles
- 2022
-
In: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 24:39, s. 24062-24075
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Journal article (peer-reviewed)abstract
- We study the influence of media on the interaction of ultra-fine plasmonic nanoparticles (≤ 8 nm) with radiation. The important role of the surface layer of the nanoparticles, with properties that differ from the ones in the inner part, is established. Using an atomistic representation of the nanoparticle material and its interaction with light, we find a highly inhomogeneous distribution of the electric field inside and around the particles. It is predicted that with an increase in the refractive index of the ambient medium, the extension of the surface layer of atoms increases, something that also is accompanied by an enhanced red shift of the plasmon resonance band compared to large particles in which the influence of this layer and its relative volume is reduced. It is shown that the physical origin for the formation of a surface layer of atoms near the nanoparticle boundary is related to the anisotropy of the local environment of atoms in this layer which changes the conditions for the interaction of neighboring atoms with each other and with the incident radiation. It is shown that a growth of the refractive index of the ambient medium results in an increase in the local field in the dielectric cavity in which a plasmonic nanoparticle is embedded and which is accompanied by a growth of the amplitude of the plasmon resonance. We predict that in the ultra-fine regime the refractive index sensitivity shows a decreasing trend with respect to size which is opposite to that for larger particles. With the applied atomistic model this work demonstrates close relations between field distributions and properties of ultra-fine nanoparticles.
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| 20. |
- Utyushev, A. D., et al.
(author)
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Engineering novel tunable optical high-Q nanoparticle array filters for a wide range of wavelengths
- 2020
-
In: Optics Express. - : Optical Society of America. - 1094-4087. ; 28:2, s. 1426-1438
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Journal article (peer-reviewed)abstract
- The interaction of non-monochromatic radiation with arrays comprising plasmonic and dielectric nanoparticles has been studied using the finite-difference time-domain electrodynamics method. It is shown that LiNbO3, TiO2, GaAs, Si, and Ge all-dielectric nanoparticle arrays can provide a complete selective reflection of an incident plane wave within a narrow spectral line of collective lattice resonance with a Q-factor of 103 or larger at various spectral ranges, while plasmonic refractory TiN and chemically stable Au nanoparticle arrays provide high-Q resonances with moderate reflectivity. Arrays with fixed dimensional parameters make it possible to fine-tune the position of a selected resonant spectral line by tilting the array relative to the direction of the incident radiation. These effects provide grounds for engineering novel selective tunable optical high-Q filters in a wide range of wavelengths, from visible to middle-IR.
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| 21. |
- Zakomirnyi, Vadim, et al.
(author)
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Titanium nitride nanoparticles as an alternative platform for plasmonic waveguides in the visible and telecommunication wavelength ranges
- 2018
-
In: Photonics and Nanostructures - Fundamentals and Applications. - : Elsevier. - 1569-4410. ; 30, s. 50-56
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Journal article (peer-reviewed)abstract
- We propose to utilize titanium nitride (TiN) as an alternative material for linear periodic chains (LPCs) of nanoparticles (NPs) which support surface plasmon polariton (SPP) propagation. Dispersion and transmission properties of LPCs have been examined within the framework of the dipole approximation for NPs with various shapes: spheres, prolate and oblate spheroids. It is shown that LPCs of TiN NPs support high-Q eigenmodes for an SPP attenuation that is comparable with LPCs from conventional plasmonic materials such as Au or Ag, with the advantage that the refractory properties and cheap fabrication of TiN nanostructures are more preferable in practical implementations compared to Au and Ag. We show that the SPP decay in TiN LPCs remains almost the same even at extremely high temperatures which is impossible to reach with conventional plasmonic materials. Finally, we show that the bandwidth of TiN LPCs from non-spherical particles can be tuned from the visible to the telecommunication wavelength range by switching the SPP polarization, which is an attractive feature for integrating these structures into modern photonic devices.
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| 22. |
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| 23. |
- Danilin, B.V., et al.
(author)
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Three-body continuum energy correlations in Borromean halo nuclei. III. Short-range external fields
- 2007
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In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 76, s. 064612-
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Journal article (peer-reviewed)abstract
- Energy correlations in transition from the bound state to the three-body continuum of Borromean halo nuclei are considered. A core+n+n three-body cluster model which reproduces the experimentally known properties of 6He and 11Li has been used to study the low-lying resonances and soft modes. An analysis of the correlated responses in 6He shows that in the case of the narrow 2+ resonance the transition energy correlations are the same as in the intrinsic correlated structure in 3->3 scattering. They differ significantly for wide second 2+ and first 1+ resonances, and also for the soft dipole and monopole modes, where due to the transition operators, the intertwinning of the ground state and the three-body continuum plays a significant role.
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| 24. |
- Ershov, S. N., et al.
(author)
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Binding energy constraint on matter radius and soft dipole excitations of C-22
- 2012
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In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 86:3
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Journal article (peer-reviewed)abstract
- An unusually large value of the C-22 matter radius has recently been extracted from measured reaction cross sections. The giant size can be explained by a very loose binding that is, however, not known experimentally yet. Within the three-body cluster model we have explored the sensitivity of the s-motion-dominated C-22 geometry to the two-neutron separation energy. A low energy of a few tens of keV is required to reach the alleged experimental lower value of the matter radius, while the experimental mean radius requires an extremely tiny binding. The dependence of the C-22 charge radius on the two-neutron separation energy is also presented. The soft dipole mode in C-22 is shown to be strongly affected by the loose binding and should be studied in the process of Coulomb fragmentation.
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| 25. |
- Ershov, S. N., et al.
(author)
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Cluster model with core excitations. The Be-11 example
- 2014
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In: Physics of Atomic Nuclei. - : Pleiades Publishing Ltd. - 1562-692X .- 1063-7788. ; 77:8, s. 989-998
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Journal article (peer-reviewed)abstract
- Bound states and low-lying resonances of the Be-11 one-neutron halo nucleus have been calculated within a two-body cluster model with core excitation. The lowest Be-10 core excited 2(+) state was considered as a quadrupole vibration. Shallow potentials were applied for neutron-core interaction, preventing motion in Pauli forbidden orbits. A good description of available experimental data including dipole excitations of Be-11 was obtained. For the bound 1/2(-) excited state the wave-function component gives the dominant contribution to the structure, which differs from results obtained in cluster models with deep potentials.
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