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Your search keyword '"Konstantinopoulos, T."' showing total 6 results
Start Over Author "Konstantinopoulos, T." Topic nuclear theory
6 results on '"Konstantinopoulos, T."'

1. High-resolution spectroscopy of neutron-rich Br isotopes and signatures for a prolate-to-oblate shape transition at N=56

Author

Dudouet, J., Colombi, G., Tello, D. Reygadas, Michelagnoli, C., Dao, D. D., Nowacki, F., Abushawish, M., Clément, E., Costache, C., Duchêne, G., Kandzia, F., Lemasson, A., Marginean, N., Marginean, R., Mihai, C., Pascu, S., Rejmund, M., Rezynkina, K., Stezowski, O., Turturica, A., Ujeniuc, S., Astier, A., de Angelis, G., de France, G., Delafosse, C., Deloncle, I., Gadea, A., Gottardo, A., Jones, P., Konstantinopoulos, T., Kuti, I., Blanc, F. Le, Lenzi, S. M., Lozeva, R., Million, B., Pérez-Vidal, R. M., Petrache, C. M., Ralet, D., Redon, N., Schmitt, C., Sohler, D., and Verney, D.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The first systematic experimental study of the neutron-rich Br isotopes with two complementary state-of-the-art techniques is presented. These isotopes have been populated in the fission process at two different facilities, GANIL and ILL. New spectroscopic information has been obtained for odd-even $^{87-93}$Br isotopes and the experimental results have been compared with state-of-the-art Large-Scale Shell-Model and DNO Shell-Model calculations. As a result of such theoretical approaches, a transition from prolate ($^{87,89}$Br) to oblate ($^{91,93}$Br) shapes is obtained from the subtle balance between proton and neutron quadrupole deformations, as a clear signature of pseudo-SU3 quadrupole regime., Comment: 17 pages, 24 figures, 5 tables

Published
2024
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2. Excitations of the magic N=50 neutron-core revealed in Ga 81

Author

Dudouet, J., Lemasson, A., Maquart, G., Nowacki, F., Verney, D., Rejmund, M., Duchêne, G., Stezowski, O., Clément, E., Michelagnoli, C., Korichi, A., Andreoiu, C., Astier, A., De Angelis, G., De France, G., Delafosse, C., Deloncle, I., Didierjean, F., Dombrádi, Zs., Ducoin, C., Gadea, Andrés, Gottardo, A., Guinet, D., Jacquot, B., Jones, P., Konstantinopoulos, T., Kuti, I., Le Blanc, F., Lenzi, Silvia M., Li, G., Lozeva, R., Million, B., Napoli, D.R., Navin, A., Pérez-Vidal, R. M., Petrache, C.M., Ralet, D., Ramdhane, M., Redon, N., Schmitt, C., Sohler, D., Ministerio de Economía y Competitividad (España), and Ministerio de Ciencia, Innovación y Universidades (España)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Physics::Atomic and Molecular Clusters, Nuclear Experiment
Abstract

The high-spin states of the neutron-rich Ga81, with three valence protons outside a Ni78 core, were measured. The measurement involved prompt γ-ray spectroscopy of fission fragments isotopically identified using the combination of the variable mode spectrometer (VAMOS++) and the advanced gamma tracking array (AGATA). The new γ-ray transitions, observed in coincidence with Ga81 ions, and the corresponding level scheme do not confirm the high-spin levels reported earlier. The newly observed high-spin states in Ga81 are interpreted using the results of state-of-the-art large-scale shell model (LSSM) calculations. The lower excitation energy levels are understood as resulting from the recoupling of three valence protons to the closed doubly magic core, while the highest excitation energy levels correspond to excitations of the magic N=50 neutron core. These results support the doubly magic character of Ni78 and the persistence of the N=50 shell closure but also highlight the presence of strong proton-neutron correlations associated with the promotion of neutrons across the magic N=50 shell gap, only few nucleons away from Ni78.

Published
2019

3. Excitations of the magic $N=50$ neutron-core revealed in $^{81}$Ga

Author

Dudouet, J., Lemasson, A., Maquart, G., Nowacki, F., Verney, D., Rejmund, M., Duchêne, G., Stezowski, O., Clément, E., Michelagnoli, C., Korichi, A., Andreoiu, C., Astier, A., De Angelis, G., De France, G., Delafosse, C., Deloncle, I., Didierjean, F., Dombradi, Z., Ducoin, C., Gadea, A., Gottardo, A., Guinet, D., Jacquot, B., Jones, P., Konstantinopoulos, T., Kuti, I., Le Blanc, F., Lenzi, S.M., Li, G., Lozeva, R., Million, B., Napoli, D.R., Navin, A., Pérez-Vidal, R.M., Petrache, C.M., Ralet, D., Ramdhane, M., Redon, N., Schmitt, C., Sohler, D., Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Physics::Atomic and Molecular Clusters, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Nuclear Structure
Abstract

International audience; The high-spin states of the neutron-rich Ga81, with three valence protons outside a Ni78 core, were measured. The measurement involved prompt γ-ray spectroscopy of fission fragments isotopically identified using the combination of the variable mode spectrometer (VAMOS++) and the advanced gamma tracking array (AGATA). The new γ-ray transitions, observed in coincidence with Ga81 ions, and the corresponding level scheme do not confirm the high-spin levels reported earlier. The newly observed high-spin states in Ga81 are interpreted using the results of state-of-the-art large-scale shell model (LSSM) calculations. The lower excitation energy levels are understood as resulting from the recoupling of three valence protons to the closed doubly magic core, while the highest excitation energy levels correspond to excitations of the magic N=50 neutron core. These results support the doubly magic character of Ni78 and the persistence of the N=50 shell closure but also highlight the presence of strong proton-neutron correlations associated with the promotion of neutrons across the magic N=50 shell gap, only few nucleons away from Ni78.

Published
2019
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4. Anomalies in the Charge Yields of Fission Fragments from the U(n,f)238 Reaction

Author

Wilson, J. N., Lebois, M., Qi, L., Amador-Celdran, P., Bleuel, D., Briz, J. A., Carroll, R., Catford, Wilton, De Witte, H., Doherty, D. T., Eloirdi, R., Georgiev, G., Gottardo, A., Goasduff, A., Hadyńska-Klęk, K., Hauschild, K., Hess, H., Ingeberg, V., Konstantinopoulos, T., Ljungvall, J., Lopez-Martens, A., Lorusso, G., Lozeva, R., Lutter, R., Marini, P., Matea, I., Materna, T., Mathieu, L., Oberstedt, A., Oberstedt, S., Panebianco, S., Podolyak, Zsolt, Porta, A., Regan, Patrick, Reiter, P., Rezynkina, K., Rose, S. J., Sahin, E., Seidlitz, M., Serot, O., Shearman, Robert, Siebeck, B., Siem, S., Smith, A. G., Tveten, G. M., Verney, D., Warr, N., Zeiser, F., and Zielinska, M.

Subjects
Nuclear Theory, Physics::Atomic and Molecular Clusters, Nuclear Experiment
Abstract

Fast-neutron-induced fission of 238U at an energy just above the fission threshold is studied with a novel technique which involves the coupling of a high-efficiency γ-ray spectrometer (MINIBALL) to an inverse-kinematics neutron source (LICORNE) to extract charge yields of fission fragments via γ−γ coincidence spectroscopy. Experimental data and fission models are compared and found to be in reasonable agreement for many nuclei; however, significant discrepancies of up to 600% are observed, particularly for isotopes of Sn and Mo. This indicates that these models significantly overestimate the standard 1 fission mode and suggests that spherical shell effects in the nascent fission fragments are less important for low-energy fast-neutron-induced fission than for thermal neutron-induced fission. This has consequences for understanding and modeling the fission process, for experimental nuclear structure studies of the most neutron-rich nuclei, for future energy applications (e.g., Generation IV reactors which use fast-neutron spectra), and for the reactor antineutrino anomaly.

Published
2017

5. STUDY OF OCTUPOLE COLLECTIVITY IN Nd-146 AND Sm-148 USING THE NEW COULOMB EXCITATION SET-UP AT ALTO

Author

Komorowska, M, Zielinska, M, Napiorkowski, P, Doherty, T, Wrzosek-Lipska, Kasia, Butler, PA, Prochniak, L, Korten, W, Briselet, R, De Witte, Hilde, Gaffney, Liam, Georgiev, G, Goasduff, A, Gorgen, A, Gottardo, A, Gregor, ET, Hadynska-Klek, K, Hess, H, Klintefjord, M, Konstantinopoulos, T, Ljungvall, J, Lutter, R, Matea, I, Matuszczak, P, O'Neill, GG, Piatek, W, Reiter, P, Rosiak, D, Scheck, M, Seidlitz, M, Siebeck, B, Thuerauf, M, and Warr, N

Subjects
Nuclear Theory
Abstract

For certain combinations of protons and neutrons in atomic nuclei, a rise of a reflection asymmetry is expected. Experimental E3 strengths, which as a function of the neutron number peak at around N ≈ 88 and N ≈ 134, indicate enhanced octupole correlations as predicted by theory. Low-energy Coulomb excitation is a highly successful method for establishing the evolution of nuclear shapes, through the measurement of cross sections, to populate excited states that can be directly related to the static and dynamic moments of the charge distribution of the nucleus. A Coulomb excitation experiment at the ALTO facility, Orsay was performed recently to study collective properties of 146Nd and 148Sm. In particular, the strengths of the ⟨3−||E3||0+⟩ and ⟨1−||E3||4+⟩ matrix elements will provide a clear distinction between octupole vibration and rigid deformation. ispartof: Acta Physica Polonica B vol:47 issue:3 pages:923-928 status: published

Published
2016

6. High-spin structures of La-138(57)81

Author

Astier, A., Konstantinopoulos, T., G. Porquet, M., Houry, M., Lucas, R., Theisen, C., CSNSM SNO, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM)

Subjects
Nuclear Theory, ROTATIONAL BANDS, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, EUROBALL, GE DETECTORS
Abstract

Odd-odd La-138 nuclei have been produced in the C-12+U-238 fusion-fission reaction and their. rays studied with the Euroball array. The high-spin level scheme has been built up to similar to 4.5 MeV excitation energy and spin I similar to 16 similar to from the triple gamma-ray coincidence data. An isomeric state lying at 739-keV excitation energy has been identified. The configurations of the structures are first discussed by analogy with the proton excitations identified in the semimagic La-139(82) nucleus, which involve the three high-j orbits lying above the Z = 50 gap, pi g(7/2), pi(5/2), and pi h(11/2). The competition of these three orbits to produce the yrast line is confirmed by the results of shell-model calculations performed in this work.

Published
2014
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