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1. Search for the γ decay of the narrow near-threshold proton resonance in 11B

Author

S. Bottoni, G. Corbari, S. Leoni, B. Fornal, A. Goasduff, S. Capra, D. Mengoni, E. Albanese, S. Ziliani, G. Benzoni, A.M. Sánchez-Benítez, A. Bracco, D. Brugnara, F. Camera, M. Ciemała, N. Cieplicka-Oryńczak, F.C.L. Crespi, J.A. Dueñas, A. Gadea, F. Galtarossa, E. Gamba, A. Gottardo, A. Gozzelino, J. Ha, Ł.W. Iskra, T. Marchi, R. Menegazzo, B. Million, D.R. Napoli, G. Pasqualato, J. Pellumaj, R.M. Pérez-Vidal, S. Pigliapoco, M. Polettini, C. Porzio, F. Recchia, K. Rezynkina, J.J. Valiente-Dóbon, O. Wieland, I. Zanon, and G. Zhang

Subjects
11B, Near-threshold resonance, γ-ray decay, Continuum shell model, Physics, QC1-999
Abstract

The γ decay of the elusive narrow, near-threshold proton resonance in 11B was investigated at Laboratori Nazionali di Legnaro (INFN) in a particle-γ coincidence experiment, using the 6Li(6Li,pγ) fusion-evaporation reaction and the GALILEO-GALTRACE setup. No clear signature was found for a possible E1 decay to the 1/21−, first-excited state of 11B, predicted by the Shell Model Embedded in the Continuum (SMEC) with a branching of 0.98−69+167×10−3 with respect to the dominant particle-decaying modes. The statistical analysis of the γ-ray spectrum provided an average upper limit of 2.37×10−3 for this γ-ray branching, with a global significance of 5σ. On the other hand, by imposing a global confidence level of 3σ, a significant excess of counts was observed for E=γ9300(20) keV, corresponding to a resonance energy of 11429(20) keV (namely 200(20) keV above the proton separation energy of 11B) and a γ-ray branching of 1.12(35)×10−3. This result is compatible with the SMEC calculations, potentially supporting the existence of a near-threshold proton resonance in 11B.

Published
2024
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2. The decay of the 21.47-MeV stretched resonance in 13C: A precise probe of the open nuclear quantum system description

Author

N. Cieplicka-Oryńczak, Y. Jaganathen, B. Fornal, S. Leoni, M. Płoszajczak, M. Ciemała, S. Ziliani, M. Kmiecik, A. Maj, J. Łukasik, P. Pawłowski, B. Sowicki, B. Wasilewska, M. Ziębliński, P. Bednarczyk, C. Boiano, S. Bottoni, A. Bracco, S. Brambilla, I. Burducea, F. Camera, I. Ciepał, C. Clisu, F.C.L. Crespi, K. Dhanmeher, N. Florea, E. Gamba, J. Grębosz, M.N. Harakeh, D.A. Iancu, Ł.W. Iskra, M. Krzysiek, P. Kulessa, N. Marginean, R. Marginean, I. Matea, M. Matejska-Minda, K. Mazurek, B. Million, W. Parol, M. Sferrazza, L. Stan, and B. Włoch

Subjects
13C, Nuclear structure, Stretched resonance states, Gamow Shell Model, Physics, QC1-999
Abstract

The decay of the 21.47-MeV stretched resonance in 13C, arising from p3/2→d5/2 nucleon excitation coupled to maximum spin, was investigated in a (p,p′) experiment at 135 MeV proton bombarding energy, performed at the Cyclotron Centre Bronowice (CCB) at IFJ PAN in Krakow. First experimental information on the proton and neutron decay branches from this state was obtained by using coincidence measurement of protons inelastically scattered on a 13C target and γ rays from daughter nuclei, namely, 12B (proton decay) and 12C (neutron decay). The main branches lead to the Jπ=2+, first-excited state at 0.953 MeV in 12B, and to the Jπ=1+, T=1 level at 15.110 MeV in 12C. The results were compared with predictions from the Gamow Shell Model (GSM), which was used to describe the stretched resonance in terms of its energy, width, electromagnetic transition strengths and decay pattern. A very good agreement was obtained between the measured and calculated properties of the 21.47-MeV stretched resonance in 13C, demonstrating the high-quality and precision of the GSM wave function calculations, which include coupling to the resonant and non-resonant particle continuum.

Published
2022
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3. The structure of low-lying 1− states in 90,94Zr from (α,α′γ) and (p,p′γ) reactions

Author

F.C.L. Crespi, A. Bracco, E.G. Lanza, A. Tamii, N. Blasi, F. Camera, O. Wieland, N. Aoi, D.L. Balabanski, S. Bassauer, A.S. Brown, M.P. Carpenter, J.J. Carroll, M. Ciemała, A. Czeszumska, P.J. Davies, V. Derya, L.M. Donaldson, Y.D. Fang, H. Fujita, G. Gey, H.T. Ha, M.N. Harakeh, T. Hashimoto, N. Ichige, E. Ideguchi, A. Inoue, J. Isaak, C. Iwamoto, D.G. Jenkins, T. Klaus, N. Kobayashi, T. Koike, M. Krzysiek, M.K. Raju, M. Liu, A. Maj, L. Morris, P. von Neumann Cosel, S. Noji, H.J. Ong, S.G. Pickstone, N. Pietralla, D. Savran, J.M. Schmitt, M. Spieker, G. Steinhilber, C. Sullivan, B. Wasilewska, M. Weinert, V. Werner, Y. Yamamoto, T. Yamamoto, R.G.T. Zegers, X. Zhou, S. Zhu, and A. Zilges

Subjects
Nuclear structure, Dipole excitation around neutron threshold, Inelastic scattering, Physics, QC1-999
Abstract

The low-lying dipole strength in the 90,94Zr nuclei was investigated via (p,p′γ) at 80 MeV and (α,α′γ) at 130 MeV. The experiments, made at RCNP, used the magnetic spectrometer Grand Raiden for the scattered particles and the array CAGRA with HPGe detectors for the γ-decay. For 94Zr these are the first data for both reactions and for 90Zr these are the first data with (p,p′γ) and the first ones at high resolution for (α,α′γ). The comparison of the present results for the two nuclei with existing (γ,γ′) data shows that both nuclear probes produce an excitation pattern different than that of the electromagnetic probes.DWBA calculations were made using form factors deduced from transition densities, based on RPA calculations, characterized by a strong neutron component at the nuclear surface. A combined analysis of the two reactions was performed for the first time to investigate the isoscalar character of the 1− states in 90,94Zr. The (p,p′γ) cross section was calculated using values for the isoscalar electric dipole energy-weighted sum rule (E1 ISEWSR) obtained from the (α,α′γ) data. The isoscalar strength for 90Zr was found to exhaust 20 ± 2.5% of the EWSR in the energy range up to 12 MeV. In case of 94Zr, a strength of 9 ± 1.1% of the EWSR was found in the range up to 8.5 MeV.Although an overall general description was obtained in the studied energy intervals, not all proton cross sections were well reproduced using the isoscalar strength from (α,α′γ). This might suggest mixing of isoscalar and isovector components and that this mixing and the degree of collectivity are not the same for all the 1− states below the particle binding energy.

Published
2021
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4. Low-lying electric dipole γ-continuum for the unstable 62,64Fe nuclei: Strength evolution with neutron number

Author

R. Avigo, O. Wieland, A. Bracco, F. Camera, F. Ameil, T. Arici, A. Ataç, D. Barrientos, D. Bazzacco, P. Bednarczyk, G. Benzoni, B. Birkenbach, N. Blasi, H.C. Boston, S. Bottoni, S. Brambilla, B. Bruyneel, M. Ciemała, E. Clément, M.L. Cortés, F.C.L. Crespi, D.M. Cullen, D. Curien, F. Didierjean, C. Domingo-Pardo, G. Duchêne, J. Eberth, A. Görgen, A. Gadea, J. Gerl, N. Goel, P. Golubev, V. González, M. Górska, A. Gottardo, E. Gregor, G. Guastalla, T. Habermann, L.J. Harkness-Brennan, A. Jungclaus, M. Kmiecik, I. Kojouharov, W. Korten, N. Kurz, M. Labiche, N. Lalović, S. Leoni, M. Lettmann, A. Maj, R. Menegazzo, D. Mengoni, E. Merchan, B. Million, A.I. Morales, D.R. Napoli, C. Nociforo, J. Nyberg, N. Pietralla, S. Pietri, Zs. Podolyák, V.Yu. Ponomarev, A. Pullia, B. Quintana, G. Rainovski, D. Ralet, F. Recchia, M. Reese, P. Regan, P. Reiter, S. Riboldi, D. Rudolph, M.D. Salsac, E. Sanchis, L.G. Sarmiento, H. Schaffner, J. Simpson, O. Stezowski, J.J. Valiente-Dobón, and H.J. Wollersheim

Subjects
64Fe, 62Fe, Nuclear structure, Dipole excitation around neutron threshold, Physics, QC1-999
Abstract

The γ-ray emission from the nuclei 62,64Fe following Coulomb excitation at bombarding energy of 400-440 AMeV was measured with special focus on E1 transitions in the energy region 4-8 MeV. The unstable neutron-rich nuclei 62,64Fe were produced at the FAIR-GSI laboratories and selected with the FRS spectrometer. The γ decay was detected with AGATA. From the measured γ-ray spectra the summed E1 strength is extracted and compared to microscopic quasi-particle phonon model calculations. The trend of the E1 strength with increasing neutron number is found to be fairly well reproduced with calculations that assume a rather complex structure of the 1− states (three-phonon states) inducing a strong fragmentation of the E1 nuclear response below the neutron binding energy.

Published
2020
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5. M4 Resonances in Light Nuclei Studied at CCB

Author

N. Cieplicka-Oryńczak, B. Fornal, M. Ciemała, M. Kmiecik, A. Maj, J. Łukasik, P. Pawłowski, B. Sowicki, B. Wasilewska, M. Ziębliński, P. Bednarczyk, I. Ciepał, K. Dhanmeher, J. Grębosz, Ł.W. Iskra, M. Krzysiek, M. Matejska-Minda, K. Mazurek, W. Parol, B. Włoch, C. Boiano, S. Brambilla, B. Million, Y. Jaganathen, M. Płoszajczak, I. Burducea, C. Clisu, N. Florea, D.A. Iancu, N. Marginean, R. Marginean, L. Stan, M.N. Harakeh, P. Kulessa, I. Matea, M. Sferrazza, Grand Accélérateur National d'Ions Lourds (GANIL), 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), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], General Physics and Astronomy
Abstract

International audience; M4 resonances in light nuclei result from the p3/2 → d5/2 stretched excitations. Their configurations should be relatively simple, which makes them good benchmarks for the theoretical calculations taking into account the role of continuum couplings. The first experimental studies aiming at tracing the decay of the M4 stretched resonance in 13C, located at 21.47 MeV, were undertaken at the Cyclotron Centre Bronowice at the Institute of Nuclear Physics Polish Academy of Sciences in Kraków, Poland (IFJ PAN). They provided information on the proton and neutron decay channels of this resonance to 12B and 12C daughter nuclei, respectively. These experimental results were then compared with the theoretical calculations based on the Gamow Shell Model approach, in terms of energy, width, and in particular, the decay pattern. Furthermore, the studies of the next cases, namely, 14N and 16O, where several M4 resonances appear at around 20 MeV, have been recently performed at CCB. The new experimental findings will serve as a testing ground for future calculations describing the heavier nuclei in this important region of the nuclear chart.

Published
2022

7. Feeding of the Residual States with GDR gamma Decay Studied by nuBall Coupled with PARIS

Author

M. Ciemała, M. Kmiecik, A. Maj, B. Fornal, P. Bednarczyk, N. Cieplicka-Oryńczak, Ł.W. Iskra, M. Matejska-Minda, K. Mazurek, B. Wasilewska, M. Ziębliński, F.C.L. Crespi, A. Bracco, S. Bottoni, F. Camera, S. Leoni, G. Benzoni, B. Million, O. Wieland, S. Brambilla, J. Wilson, I. Matea, M. Lebois, N. Jovančević, O. Dorvaux, Ch. Schmitt, J. Dudek, S. Kihel, P.J. Napiorkowski, M. Kicińska-Habior, I. Mazumdar, and V. Nanal

Subjects
General Physics and Astronomy
Published
2023

8. γ decay to the ground state from the excitations above the neutron threshold in the Pb208(p,p′γ) reaction at 85 MeV

Author

B. Wasilewska, M. Kmiecik, M. Ciemała, A. Maj, F. C. L. Crespi, A. Bracco, M. N. Harakeh, P. Bednarczyk, S. Bottoni, S. Brambilla, F. Camera, I. Ciepał, N. Cieplicka-Oryńczak, M. Csatlos, B. Fornal, V. Gaudilla, J. Grȩbosz, J. Isaak, Ł. W. Iskra, M. Jeżabek, A. J. Krasznahorkay, S. Kihel, M. Krzysiek, P. Lasko, S. Leoni, M. Lewitowicz, J. Łukasik, M. Matejska-Minda, K. Mazurek, P. J. Napiorkowski, W. Parol, P. Pawłowski, L. Q. Qi, M. Saxena, Ch. Schmitt, Y. Sobolev, B. Sowicki, M. Stanoiu, A. Tamii, O. Wieland, and M. Ziȩbliński

Published
2022

9. $^{178}$Hg and asymmetric fission of neutron-deficient pre-actinides

Author

A. Jhingan, C. Schmitt, A. Lemasson, S. Biswas, Y. H. Kim, D. Ramos, A. N. Andreyev, D. Curien, M. Ciemała, E. Clément, O. Dorvaux, B. De Canditiis, F. Didierjean, G. Duchêne, J. Dudouet, J. Frankland, G. Frémont, J. Goupil, B. Jacquot, C. Raison, D. Ralet, B.-M. Retailleau, L. Stuttgé, I. Tsekhanovich, A. V. Andreev, S. Goriely, S. Hilaire, J.-F. Lemaître, P. Möller, K.-H. Schmidt, Institut Pluridisciplinaire Hubert Curien (IPHC), 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), Grand Accélérateur National d'Ions Lourds (GANIL), 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), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), 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), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Direction des Applications Militaires (DAM), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Nuclear Theory (nucl-th), Nuclear Theory, FOS: Physical sciences, Nuclear Physics - Experiment, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

Fission at low excitation energy is an ideal playground to probe the impact of nuclear structure on nuclear dynamics. While the importance of structural effects in the nascent fragments is well established in the (trans-)actinide region, the observation of asymmetric fission in several neutron-deficient pre-actinides can be explained by various mechanisms. To deepen our insight into that puzzle, an innovative approach based on inverse kinematics and an enhanced version of the VAMOS++ heavy-ion spectrometer was implemented at the GANIL facility, Caen. Fission of $^{178}$Hg was induced by fusion of $^{124}$Xe and $^{54}$Fe. The two fragments were detected in coincidence using VAMOS++ supplemented with a new SEcond Detection arm. For the first time in the pre-actinide region, access to the pre-neutron mass and total kinetic energy distributions, and the simultaneous isotopic identification of one the fission fragment, was achieved. The present work describes the experimental approach, and discusses the pre-neutron observables in the context of an extended asymmetricfission island located southwest of $^{208}$Pb. A comparison with different models is performed, demonstrating the importance of this new asymmetric-fission island for elaborating on driving effects in fission. Fission at low excitation energy is an ideal playground to probe the impact of nuclear structure on nuclear dynamics. While the importance of structural effects in the nascent fragments is well-established in the (trans-)actinide region, the observation of asymmetric fission in several neutron-deficient pre-actinides can be explained by various mechanisms. To deepen our insight into that puzzle, an innovative approach based on inverse kinematics and an enhanced version of the VAMOS++ heavy-ion spectrometer was implemented at the GANIL facility, Caen. Fission of $^{178}$Hg was induced by fusion of $^{124}$Xe and $^{54}$Fe. The two fragments were detected in coincidence using VAMOS++ supplemented with a new SEcond Detection arm. For the first time in the pre-actinide region, access to the pre-neutron mass and total kinetic energy distributions, and the simultaneous isotopic identification of one the fission fragment, was achieved. The present work describes the experimental approach, and discusses the pre-neutron observables in the context of an extended asymmetric-fission island located south-west of $^{208}Pb. A comparison with different models is performed, demonstrating the importance of this "new" asymmetric-fission island for elaborating on driving effects in fission.

Published
2022
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10. Spectroscopy of neutron-rich nitrogen isotopes with Agata+Paris+Vamos

Author

S. Ziliani, M. Ciemała, F.C.L. Crespi, S. Leoni, B. Fornal, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Oryńczak, E. Clément, S. Coelli, O. Dorvaux, S. Erturk, G. de France, C. Fransen, A. Goldkuhle, J. Grębosz, M.N. Harakeh, Ł.W. Iskra, B. Jacquot, A. Karpov, M. Kicińska-Habior, Y. Kim, M. Kmiecik, A. Lemasson, S.M. Lenzi, M. Lewitowicz, H. Li, I. Matea, K. Mazurek, C. Michelagnoli, M. Matejska-Minda, B. Million, C. Müller-Gatermann, V. Nanal, P. Napiorkowski, D.R. Napoli, R. Palit, M. Rejmund, Ch. Schmitt, M. Stanoiu, I. Stefan, E. Vardaci, B. Wasilewska, O. Wieland, M. Ziębliński, M. Zielińska, Ziliani, S., Ciemała, M., Crespi, F. C. L., Leoni, S., Fornal, B., Maj, A., Bednarczyk, P., Benzoni, G., Bracco, A., Boiano, C., Bottoni, S., Brambilla, S., Bast, M., Beckers, M., Braunroth, T., Camera, F., Cieplicka-Orynczak, N., Clément, E., Coelli, S., Dorvaux, O., Erturk, S., de France, G., Fransen, C., Goldkuhle, A., Grebosz, J., Harakeh, M. N., Iskra, Ł. W., Jacquot, B., Karpov, A., Kicinska-Habior, M., Kim, Y., Kmiecik, M., Lemasson, A., Lenzi, S. M., Lewitowicz, M., Li, H., Matea, I., Mazurek, K., Michelagnoli, C., Matejska-Minda, M., Million, B., Müller-Gatermann, C., Nanal, V., Napiorkowski, P., Napoli, D. R., Palit, R., Rejmund, M., Schmitt, Ch., Stanoiu, M., Stefan, I., Vardaci, E., Wasilewska, B., Wieland, O., Zieblinski, M., Zielinska, M., Grand Accélérateur National d'Ions Lourds (GANIL), 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), Institut Pluridisciplinaire Hubert Curien (IPHC), 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), Institut de Physique Nucléaire d'Orsay (IPNO), 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), Institut Laue-Langevin (ILL), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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 National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), 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), ILL, and Research unit Nuclear & Hadron Physics

Subjects
Physics, education.field_of_study, Spectrometer, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Population, Gamma ray, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Excited state, 0103 physical sciences, Neutron, AGATA, 010306 general physics, Spectroscopy, education, Beam (structure)
Abstract

Excited states of 17N, 18N and 19N were investigated through the measurement of gamma rays, following their population via deep-inelastic reactions induced by an 18O beam (7 MeV/u) on a thick 181Ta target. The experimental setup comprised the AGATA+PARIS detection system, coupled to the VAMOS++ magnetic spectrometer. In the 17N nucleus, the analysis of gamma-ray transitions de-exciting two states around 4-5 MeV clearly pointed to discrepancies with the lifetime values reported in literature. Three new gamma rays were observed in 18N at the energies of 1662.3 (3) keV, 2073.4 (8) keV and 2300.9 (8) keV, and hints for other two new transitions around 1566 keV and 1720 keV were found. In addition, a new transition with energy of 2489.7 (8) keV was observed in 19N.

Published
2020

11. Complete set of bound negative-parity states in the neutron-rich nucleus 18N

Author

S. Ziliani, M. Ciemała, F. C. L. Crespi, S. Leoni, B. Fornal, T. Suzuki, T. Otsuka, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Oryńczak, E. Clément, S. Coelli, O. Dorvaux, S. Erturk, G. de France, C. Fransen, A. Goldkuhle, J. Grębosz, M. N. Harakeh, Ł. W. Iskra, B. Jacquot, A. Karpov, M. Kicińska-Habior, Y. Kim, M. Kmiecik, A. Lemasson, S. M. Lenzi, M. Lewitowicz, H. Li, I. Matea, K. Mazurek, C. Michelagnoli, M. Matejska-Minda, B. Million, C. Müller-Gatermann, V. Nanal, P. Napiorkowski, D. R. Napoli, R. Palit, M. Rejmund, Ch. Schmitt, M. Stanoiu, I. Stefan, E. Vardaci, B. Wasilewska, O. Wieland, M. Ziębliński, M. Zielińska, 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 Laue-Langevin (ILL), ILL, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
Set (abstract data type), Physics, Particle physics, medicine.anatomical_structure, 010308 nuclear & particles physics, 0103 physical sciences, medicine, Neutron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Parity (mathematics), 01 natural sciences, Nucleus
Abstract

International audience; High-resolution γ-ray spectroscopy of N18 is performed with the Advanced GAmma Tracking Array, following deep-inelastic processes induced by an O18 beam on a Ta181 target. Six states are newly identified, which together with the three known excitations exhaust all negative-parity excited states expected in N18 below the neutron threshold. Spin and parities are proposed for all located states on the basis of decay branchings and comparison with large-scale shell-model calculations performed in the p-sd space, with the YSOX interaction. Of particular interest is the location of the 01− and 12− excitations, which provide strong constrains for cross-shell p-sd matrix elements based on realistic interactions and help to simultaneously reproduce the ground and first-excited states in N16 and N18, for the first time. Understanding the N18 structure may also have significant impact on neutron-capture cross-section calculations in r-process modeling including light neutron-rich nuclei.

Published
2021

12. The structure of low-lying 1− states in 90,94Zr from (α,α′γ) and (p,p′γ) reactions

Author

Miao Liu, T. Hashimoto, J.M. Schmitt, X. K. Zhou, O. Wieland, C. Iwamoto, Norbert Pietralla, B. Wasilewska, S. Zhu, A. Czeszumska, Johann Isaak, T. Klaus, C. Sullivan, A. Inoue, M.K. Raju, Y.D. Fang, Nobuyuki Kobayashi, F. Camera, Yoshihisa Yamamoto, Shumpei Noji, V. Werner, A. Maj, G. Gey, D. G. Jenkins, Hooi Jin Ong, M. Krzysiek, F. C. L. Crespi, Andreas Zilges, M. Ciemała, L. Morris, R. G. T. Zegers, Takeshi Koike, T. Yamamoto, M. P. Carpenter, G. Steinhilber, D. L. Balabanski, A. Bracco, S. Bassauer, V. Derya, Nori Aoi, J. J. Carroll, E.G. Lanza, M. Spieker, A. S. Brown, N. Ichige, Deniz Savran, H. Fujita, S. G. Pickstone, N. Blasi, P. J. Davies, P. von Neumann Cosel, M.N. Harakeh, H.T. Ha, Atsushi Tamii, M. Weinert, L. M. Donaldson, Eiji Ideguchi, and Research unit Nuclear & Hadron Physics

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Inelastic scattering, Isovector, Proton, 010308 nuclear & particles physics, Isoscalar, Binding energy, 01 natural sciences, Dipole excitation around neutron threshold, lcsh:QC1-999, Dipole, 0103 physical sciences, Neutron, Sum rule in quantum mechanics, Nuclear structure, Atomic physics, 010306 general physics, lcsh:Physics
Abstract

The low-lying dipole strength in the 90,94Zr nuclei was investigated via (p,p′γ) at 80 MeV and (α,α′γ) at 130 MeV. The experiments, made at RCNP, used the magnetic spectrometer Grand Raiden for the scattered particles and the array CAGRA with HPGe detectors for the γ-decay. For 94Zr these are the first data for both reactions and for 90Zr these are the first data with (p,p′γ) and the first ones at high resolution for (α,α′γ). The comparison of the present results for the two nuclei with existing (γ,γ′) data shows that both nuclear probes produce an excitation pattern different than that of the electromagnetic probes. DWBA calculations were made using form factors deduced from transition densities, based on RPA calculations, characterized by a strong neutron component at the nuclear surface. A combined analysis of the two reactions was performed for the first time to investigate the isoscalar character of the 1− states in 90,94Zr. The (p,p′γ) cross section was calculated using values for the isoscalar electric dipole energy-weighted sum rule (E1 ISEWSR) obtained from the (α,α′γ) data. The isoscalar strength for 90Zr was found to exhaust 20 ± 2.5% of the EWSR in the energy range up to 12 MeV. In case of 94Zr, a strength of 9 ± 1.1% of the EWSR was found in the range up to 8.5 MeV. Although an overall general description was obtained in the studied energy intervals, not all proton cross sections were well reproduced using the isoscalar strength from (α,α′γ). This might suggest mixing of isoscalar and isovector components and that this mixing and the degree of collectivity are not the same for all the 1− states below the particle binding energy.

Published
2021

13. Shape Coexistence at Zero Spin in ^{64}Ni Driven by the Monopole Tensor Interaction

Author

N, Mărginean, D, Little, Y, Tsunoda, S, Leoni, R V F, Janssens, B, Fornal, T, Otsuka, C, Michelagnoli, L, Stan, F C L, Crespi, C, Costache, R, Lica, M, Sferrazza, A, Turturica, A D, Ayangeakaa, K, Auranen, M, Barani, P C, Bender, S, Bottoni, M, Boromiza, A, Bracco, S, Călinescu, C M, Campbell, M P, Carpenter, P, Chowdhury, M, Ciemała, N, Cieplicka-Oryǹczak, D, Cline, C, Clisu, H L, Crawford, I E, Dinescu, J, Dudouet, D, Filipescu, N, Florea, A M, Forney, S, Fracassetti, A, Gade, I, Gheorghe, A B, Hayes, I, Harca, J, Henderson, A, Ionescu, Ł W, Iskra, M, Jentschel, F, Kandzia, Y H, Kim, F G, Kondev, G, Korschinek, U, Köster, Krishichayan, M, Krzysiek, T, Lauritsen, J, Li, R, Mărginean, E A, Maugeri, C, Mihai, R E, Mihai, A, Mitu, P, Mutti, A, Negret, C R, Niţă, A, Olăcel, A, Oprea, S, Pascu, C, Petrone, C, Porzio, D, Rhodes, D, Seweryniak, D, Schumann, C, Sotty, S M, Stolze, R, Şuvăilă, S, Toma, S, Ujeniuc, W B, Walters, C Y, Wu, J, Wu, S, Zhu, and S, Ziliani

Abstract

The low-spin structure of the semimagic ^{64}Ni nucleus has been considerably expanded: combining four experiments, several 0^{+} and 2^{+} excited states were identified below 4.5 MeV, and their properties established. The Monte Carlo shell model accounts for the results and unveils an unexpectedly complex landscape of coexisting shapes: a prolate 0^{+} excitation is located at a surprisingly high energy (3463 keV), with a collective 2^{+} state 286 keV above it, the first such observation in Ni isotopes. The evolution in excitation energy of the prolate minimum across the neutron N=40 subshell gap highlights the impact of the monopole interaction and its variation in strength with N.

Published
2020

14. Testing ab initio nuclear structure in neutron-rich nuclei: Lifetime measurements of second 2+ state in C16 and O20

Author

M. Ciemała, S. Ziliani, F. C. L. Crespi, S. Leoni, B. Fornal, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Oryńczak, E. Clément, S. Coelli, O. Dorvaux, S. Erturk, G. de France, C. Fransen, A. Goldkuhle, J. Grębosz, M. N. Harakeh, Ł. W. Iskra, B. Jacquot, A. Karpov, M. Kicińska-Habior, Y. Kim, M. Kmiecik, A. Lemasson, S. M. Lenzi, M. Lewitowicz, H. Li, I. Matea, K. Mazurek, C. Michelagnoli, M. Matejska-Minda, B. Million, C. Müller-Gatermann, V. Nanal, P. Napiorkowski, D. R. Napoli, R. Palit, M. Rejmund, Ch. Schmitt, M. Stanoiu, I. Stefan, E. Vardaci, B. Wasilewska, O. Wieland, M. Zieblinski, M. Zielińska, A. Ataç, D. Barrientos, B. Birkenbach, A. J. Boston, B. Cederwall, L. Charles, J. Collado, D. M. Cullen, P. Désesquelles, C. Domingo-Pardo, J. Dudouet, J. Eberth, V. González, J. Goupil, L. J. Harkness-Brennan, H. Hess, D. S. Judson, A. Jungclaus, W. Korten, M. Labiche, A. Lefevre, R. Menegazzo, D. Mengoni, J. Nyberg, R. M. Perez-Vidal, Zs. Podolyak, A. Pullia, F. Recchia, P. Reiter, F. Saillant, M. D. Salsac, E. Sanchis, O. Stezowski, Ch. Theisen, J. J. Valiente-Dobón, J. D. Holt, J. Menéndez, A. Schwenk, and J. Simonis

Subjects
Physics, 010308 nuclear & particles physics, 0103 physical sciences, Nuclear structure, Ab initio, Neutron, State (functional analysis), Atomic physics, 010306 general physics, 7. Clean energy, 01 natural sciences, Nuclear theory
Abstract

To test the predictive power of ab initio nuclear structure theory, the lifetime of the second 2(+) state in neutron-rich O-20, tau(2(2)(+)) = 150(-30)(+80) fs, and an estimate for the lifetime of ...

Published
2020

15. Shape Coexistence at Zero Spin in Ni 64 Driven by the Monopole Tensor Interaction

Author

N. Mărginean, D. Little, Y. Tsunoda, S. Leoni, R. V. F. Janssens, B. Fornal, T. Otsuka, C. Michelagnoli, L. Stan, F. C. L. Crespi, C. Costache, R. Lica, M. Sferrazza, A. Turturica, A. D. Ayangeakaa, K. Auranen, M. Barani, P. C. Bender, S. Bottoni, M. Boromiza, A. Bracco, S. Călinescu, C. M. Campbell, M. P. Carpenter, P. Chowdhury, M. Ciemała, N. Cieplicka-Oryǹczak, D. Cline, C.

Published
2020
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16. $\gamma$-ray Spectroscopy of $^{85}$Se Produced in $^{232}$Th Fission

Author

I. Homm, M. Ciemała, Stephan Oberstedt, K. Rezynkina, P. A. Söderström, B. Fornal, A. Lopez-Martens, M. Bunce, V. Vedia, D. Verney, J. N. Wilson, J. Nemer, B. Wasilewska, A. Algora, M. Babo, R. B. Gerst, L. M. Fraile, Y. Popovitch, R. Chakma, T. Kurtukian-Nieto, Ł. W. Iskra, W. Paulsen, E. Adamska, D. Ralet, G. Häfner, M. Piersa, G. Benzoni, M. Rudigier, A. Fijałkowska, A. Blazhev, S. Leoni, D. Reygadas Tello, K. Hauschild, P. H. Regan, M. S. Yavahchova, J. Wiederhold, V. Guadilla, N. Warr, C. Delafosse, C. Schmitt, R.L. Canavan, V. Sánchez-Tembleque, K. Miernik, R. Lozeva, I. Matea, P. Davies, Muriel Fallot, N. Jovančević, S. Bottoni, M. Lebois, N. Cieplicka-Oryńczak, P. Adsley, C. Henrich, G. Tocabens, K. Belvedere, D. Gjestvang, T. Kröll, L. Cortes, C. Sürder, L. Qi, S. M. Collins, D. Etasse, M. Heine, Fabio Zeiser, A. Boso, F. Ibrahim, J. Benito, A. Korgul, J. Ljungvall, D. Thisse, L. Le-meur, A. Gottardo, P. Koseoglou, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), 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), Laboratoire de physique subatomique et des technologies associées (SUBATECH), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), 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), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-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), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), 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), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and 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)

Subjects
Physics, Spectrometer, Isotope, 010308 nuclear & particles physics, Fission, Yrast, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Aucun, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, Excited state, 0103 physical sciences, Neutron source, Gamma spectroscopy, Nuclear Experiment
Abstract

International audience; Excited states in the neutron-rich 85Se nucleus have been studied using for the first time a fast neutron-induced fission of 232Th. The experiment was performed at the ALTO facility of the IPN Orsay. Coupling of the LICORNE directional neutron source with the ν-ball high-resolution γ-ray spectrometer provided unique access to high-spin states in neutron-rich fission fragments from the 232Th(n, f) reaction. A preliminary level scheme of 85Se was established by the analysis of prompt γ–γ–γ coincidences. Identification of the all known yrast states in 85Se is the first step towards studies of more neutron-rich Se isotopes.

Published
2019

17. SPECTROSCOPY OF NEUTRON-RICH C, O, N AND F ISOTOPES WITH THE AGATA plus PARIS plus VAMOS SETUP AT GANIL

Author

S. Ziliani, M. Ciemała, F. Crespi, S. Leoni, B. Fornal, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Oryńczak, E. Clément, O. Dorvaux, S. Erturk, G. De France, A. Goldkuhle, J. Grębosz, M.N. Harakeh, Ł.W. Iskra, B. Jacquot, M. Kicińska-Habior, Y. Kim, M. Kmiecik, A. Lemasson, H. Li, I. Matea, K. Mazurek, C. Michelagnoli, B. Million, C. Müller-Gatermann, P. Napiorkowski, V. Nanal, M. Matejska-Minda, M. Rejmund, Ch. Schmitt, M. Stanoiu, I. Stefan, B. Wasilewska, M. Ziębliński, Fornal, Bogdan -- 0000-0002-1142-8067, Ciemala, Michal -- 0000-0001-5328-720X, [Ziliani, S. -- Crespi, F. -- Leoni, S. -- Bracco, A. -- Bottoni, S. -- Camera, F.] Univ Milan, Milan, Italy -- [Ziliani, S. -- Crespi, F. -- Leoni, S. -- Benzoni, G. -- Bracco, A. -- Boiano, C. -- Bottoni, S. -- Brambilla, S. -- Camera, F. -- Million, B.] INFN, Sez Milano, Milan, Italy -- [Ciemala, M. -- Fornal, B. -- Maj, A. -- Bednarczyk, P. -- Cieplicka-Orynczak, N. -- Grebosz, J. -- Iskra, L. W. -- Kmiecik, M. -- Mazurek, K. -- Wasilewska, B.] Polish Acad Sci, Inst Nucl Phys, Krakow, Poland -- [Bast, M. -- Beckers, M. -- Braunroth, T. -- Goldkuhle, A. -- Mueller-Gatermann, C.] IKP Cologne, Cologne, Germany -- [Clement, E. -- De France, G. -- Jacquot, B. -- Kim, Y. -- Lemasson, A. -- Li, H. -- Rejmund, M.] CEA, DSAM, GANIL, Caen, France -- [Clement, E. -- De France, G. -- Jacquot, B. -- Kim, Y. -- Lemasson, A. -- Li, H. -- Rejmund, M.] CNRS, IN2P3, Caen, France -- [Dorvaux, O. -- Schmitt, Ch] CNRS, IN2P3, IPHC UMR 7178, Strasbourg, France -- [Erturk, S.] Nigde Univ, Nigde, Turkey -- [Harakeh, M. N.] KVI Ctr Adv Radiat Technol, Groningen, Netherlands -- [Kicinska-Habior, M. -- Matea, I -- Stefan, I] Warsaw Univ, Fac Phys, Warsaw, Poland -- [Kicinska-Habior, M. -- Matea, I -- Stefan, I] IPN, Orsay Lab, Orsay, France -- [Michelagnoli, C.] ILL Grenoble, Grenoble, France -- [Napiorkowski, P. -- Matejska-Minda, M.] Univ Warsaw, Heavy Ion Lab, Warsaw, Poland -- [Nanal, V] Dept Nucl & Atom Phys, Mumbai, Maharashtra, India -- [Stanoiu, M.] IFIN HH, Bucharest, Romania -- [Zieblinski, M.] CEA, DRF, IRFU, Ctr CEA Saclay, Saclay, France, 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), Institut Laue-Langevin (ILL), ILL, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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 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), 0-Belirlenecek, and 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)

Subjects
Physics, Isotope, Spectrometer, 010308 nuclear & particles physics, General Physics and Astronomy, Context (language use), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, 0-Belirlenecek, Nuclear physics, Nuclear interaction, Ab initio quantum chemistry methods, 0103 physical sciences, Neutron, AGATA, Spectroscopy, Nuclear Experiment
Abstract

Zakopane Conference on Nuclear Physics - Extremes of the Nuclear Landscape -- AUG 26-SEP 02, 2018 -- Zakopane, POLAND, WOS: 000463866500052, Recent ab initio calculations pointed out the importance of the three-body terms of the nuclear interaction, in the description of the structure of n-rich systems. The state lifetimes in light n-rich carbon and oxygen nuclei have been predicted to be sensitive to the three-body terms and, in this context, an experiment, aiming at the measurement of these lifetimes, was performed in GANIL in July 2017 with the AGATA and PARIS arrays coupled to the VAMOS++ magnetic spectrometer. Details on the AGATA preliminary data analysis are presented., National Science Centre, Poland (NCN) [2013/08/M/ST2/00257, 2014/14/M/ST2/00738, 2016/22/M/ST2/00269], This work was supported by the National Science Centre, Poland (NCN) under contracts No. 2013/08/M/ST2/00257, 2014/14/M/ST2/00738 and 2016/22/M/ST2/00269.

Published
2019

18. Determination of Lifetimes of Excited States in Neutron-rich $^{20}$O Isotope from Experiment with the AGATA+PARIS+VAMOS Setup

Author

M. Ciemała, S. Ziliani, F. Crespi, S. Leoni, B. Fornal, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Oryńczak, E. Clément, O. Dorvaux, S. Ertürk, G. De France, A. Goldkuhle, J. Grębosz, M.N. Harakeh, Ł.W. Iskra, B. Jacquot, A. Karpov, M. Kicińska-Habior, Y. Kim, M. Kmiecik, A. Lemasson, H. Li, I. Matea, K. Mazurek, C. Michelagnoli, B. Millon, C. Müller-Gatermann, P. Napiorkowski, V. Nanal, M. Matejska-Minda, M. Rejmund, B. Sowicki, Ch. Schmitt, M. Stanoiu, I. Stefan, B. Wasilewska, M. Zielińska, M. Ziębliński, 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), Institut Laue-Langevin (ILL), ILL, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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)-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), 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), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Nuclear Theory, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, Excited state, 0103 physical sciences, AGATA, Neutron, Nuclear Experiment
Abstract

International audience; An experiment aiming at measuring lifetimes of the second 2+ excited states in neutron-rich C and O isotopes was recently performed at the GANIL laboratory, in France. In these nuclei, recent ab initio calculations provide a detailed description of the nuclear excited states, predicting a strong sensitivity of the electromagnetic transition probabilities to the details of the nucleon–nucleon interactions, especially in connection with the role played by the three-body (NNN) forces. Thus, the measurement of 2 + states lifetimes in this region will be a stringent test of the importance of including the NNN forces in describing the electromagnetic properties of selected nuclear states. This contribution reports on the status of the experimental analysis for the case of lifetimes in 20O.

Published
2018

19. Search for Jacobi Shape Transition in Hot Rotating $^{88}$Mo Nuclei Through Giant Dipole Resonance Decay

Author

M. Ciemała, M. Kmiecik, V. L. Kravchuk, A. Maj, S. Barlini, G. Casini, F. Gramegna, F. Camera, A. Corsi, L. Bardelli, P. Bednarczyk, B. Fornal, M. Matejska Minda, K. Mazurek, W. Męczyński, S. Myalski, J. Styczeń, B. Szpak, M. Ziębliński, M. Cinausero, T. Marchi, V. Rizzi, G. Prete, M. Degerlier, G. Benzoni, N. Blasi, A. Bracco, S. Brambilla, F. Crespi, S. Leoni, B. Million, O. Wieland, D. Montanari, R. Nicolini, A. Giaz, V. Vandone, M. Chiari, A. Nannini, S. Piantelli, A. Chbihi, J. P. Wieleczko, I. Mazumdar, O. Roberts, J. Dudek, BAIOCCO, GIORGIO, BRUNO, MAURO, D'AGOSTINO, MICHELA, MORELLI, LUCA, VANNINI, GIANNI, Grand Accélérateur National d'Ions Lourds (GANIL), 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), M. Ciemała, M. Kmiecik, V.L. Kravchuk, A. Maj, S. Barlini, G. Casini, F. Gramegna, F. Camera, A. Corsi, L. Bardelli, P. Bednarczyk, B. Fornal, M. Matejska-Minda, K. Mazurek, W. Męczyński, S. Myalski, J. Styczeń, B. Szpak, M. Ziębliński, M. Cinausero, T. Marchi, V. Rizzi, G. Prete, M. Degerlier, G. Benzoni, N. Blasi, A. Bracco, S. Brambilla, F. Crespi, S. Leoni, B. Million, O. Wieland, D. Montanari, R. Nicolini, A. Giaz, V. Vandone, G. Baiocco, Bruno M, M. D'Agostino, L. Morelli, G. Vannini, M. Chiari, A. Nannini, S. Piantelli, A. Chbihi, J.P. Wieleczko, I. Mazumdar, O. Robert, and J. Dudek

Subjects
GIANT DIPOLE RESONANCE, Physics and Astronomy (all), Nuclear Theory, jacobi shape transition, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, 21.10.Re, 24.30.Cz
Abstract

International audience; We report on preliminary results from the experiment performed at Legnaro National Laboratories aiming at the investigation of the shape evolution of the Mo-88 nucleus. The GDR spectra obtained for two data sets measured at Ti-48 beam energy of 300 and 450 MeV corresponding to 3 and 3.8 MeV temperatures, respectively, are presented. The low energy component in GDR strength functions, similar to the theoretical predictions of LSD model, possibly indicates the presence of Jacobi shape transition.

Published
2010

20. Isospin character of low-lying pygmy dipole states in 208Pb via inelastic scattering of 17O ions

Author

F C L, Crespi, A, Bracco, R, Nicolini, D, Mengoni, L, Pellegri, E G, Lanza, S, Leoni, A, Maj, M, Kmiecik, R, Avigo, G, Benzoni, N, Blasi, C, Boiano, S, Bottoni, S, Brambilla, F, Camera, S, Ceruti, A, Giaz, B, Million, A I, Morales, V, Vandone, O, Wieland, P, Bednarczyk, M, Ciemała, J, Grebosz, M, Krzysiek, K, Mazurek, M, Zieblinski, D, Bazzacco, M, Bellato, B, Birkenbach, D, Bortolato, E, Calore, B, Cederwall, L, Charles, G, de Angelis, P, Désesquelles, J, Eberth, E, Farnea, A, Gadea, A, Görgen, A, Gottardo, R, Isocrate, J, Jolie, A, Jungclaus, N, Karkour, W, Korten, R, Menegazzo, C, Michelagnoli, P, Molini, D R, Napoli, A, Pullia, F, Recchia, P, Reiter, D, Rosso, E, Sahin, M D, Salsac, B, Siebeck, S, Siem, J, Simpson, P-A, Söderström, O, Stezowski, Ch, Theisen, C, Ur, and J J, Valiente-Dobón

Abstract

The properties of pygmy dipole states in 208Pb were investigated using the 208Pb(17O, 17O'γ) reaction at 340 MeV and measuring the γ decay with high resolution with the AGATA demonstrator array. Cross sections and angular distributions of the emitted γ rays and of the scattered particles were measured. The results are compared with (γ, γ') and (p, p') data. The data analysis with the distorted wave Born approximation approach gives a good description of the elastic scattering and of the inelastic excitation of the 2+ and 3- states. For the dipole transitions a form factor obtained by folding a microscopically calculated transition density was used for the first time. This has allowed us to extract the isoscalar component of the 1- excited states from 4 to 8 MeV.

Published
2014

21. Lifetime measurements of short lived states in 69As

Author

M. Matejska-Minda, P. Bednarczyk, B. Fornal, M. Ciemała, M. Kmiecik, M. Krzysiek, A. Maj, W. Męczyński, S. Myalski, J. Styczeń, M. Ziębliński, G. [Angelis]de Angelis, T. Huyuk, C. Michelagnoli, E. Sahin, S. Aydin, E. Farnea, R. Menegazzo, F. Recchia, C. Ur, S. Brambilla, S. Leoni, D. Montanari, G. Jaworski, M. Palacz, R. Wadsworth, F. Xu, and W. Liang

Subjects
General Physics and Astronomy
Published
2014

22. Spin-alignment and g-factor measurement of the I(pi)=12(+) isomer in (192)Pb produced in the relativistic-energy fragmentation of a (238)U beam

Author

F. Becker, S. K. Chamoli, P. Bednarczyk, S. Mallion, W. Prokopowicz, J. M. Daugas, B. Million, W. Mȩczyński, E. Werner-Malento, A. Saltarelli, S. Chmel, M. Hass, A. Krasznahorkay, A. Maj, L. Caceres, Gerda Neyens, M. Ionescu-Bujor, D. Montanari, I. Kojuharov, P. Detistov, S. Brambilla, J. Gerl, F. Camera, P. Doornenbal, S. Pietri, M. Pfützner, M. Kmiecik, H. J. Wollersheim, Norio Saito, R. Lozeva, O. Wieland, L. Atanasova, J. Jolie, G. Ilie, J. Grȩbosz, G. S. Simpson, S. Myalski, K. H. Maier, M. Ciemała, G. Lo Bianco, Georgi P. Georgiev, N. Blasi, Dirk Rudolph, T. Saito, M. Lach, F. C. L. Crespi, Robert Hoischen, Zs. Podolyák, D. L. Balabanski, M. Ziȩbliński, N. Vermeulen, C. M. Petrache, K. Mazurek, M. Górska, A. Bracco, K. A. Gladnishki, S. Lakshmi, G. Benzoni, S. Leoni, R. Kulessa, H. Grawe, J. Styczen, DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (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), Institut Laue-Langevin (ILL), and ILL

Subjects
Physics, Nuclear and High Energy Physics, Magnetic moment, NUCLEI, 010308 nuclear & particles physics, Relativistic energy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], FISSION, 01 natural sciences, 7. Clean energy, LISE, Separation process, SEPARATORS, GSI, Fragmentation (mass spectrometry), MOMENTS, 0103 physical sciences, Pi, ISOTOPES, Atomic physics, 010306 general physics, Nuclear Experiment
Abstract

The feasibility of measuring g -factors using the TDPAD method applied to high-energy, heavy fragmentation products is explored. The 2623keV $\ensuremath I^{\pi}=12^+$ isomer in 192Pb with $ \tau$ = 1.57 μs has been produced using the fragmentation of a 1A GeV 238U beam. The results presented demonstrate for the first time that such heavy nuclei produced in a fragmentation reaction with a relativistic beam are sufficiently well spin-aligned. Moreover, the rather large value of the alignment, 28(10)% of the maximum possible, is preserved during the separation process allowing the determination of magnetic moments. The measured values of the lifetime, $ \tau$ = 1.54(9) μs, and the g -factor, g = - 0.175(20) , agree with the results of previous investigations using fusion-evaporation reactions.

Published
2010

23. Evidence of octupole-phonons at high spin in 207Pb

Author

D. Ralet, E. Clément, G. Georgiev, A.E. Stuchbery, M. Rejmund, P. Van Isacker, G. de France, A. Lemasson, J. Ljungvall, C. Michelagnoli, A. Navin, D.L. Balabanski, L. Atanasova, A. Blazhev, G. Bocchi, R. Carroll, J. Dudouet, E. Dupont, B. Fornal, S. Franchoo, C. Fransen, C. Müller-Gatermann, A. Goasduff, A. Gadea, P.R. John, D. Kocheva, T. Konstantinopoulos, A. Korichi, A. Kusoglu, S.M. Lenzi, S. Leoni, R. Lozeva, A. Maj, R. Perez, N. Pietralla, C. Shand, O. Stezowski, D. Wilmsen, D. Yordanov, D. Barrientos, P. Bednarczyk, B. Birkenbach, A.J. Boston, H.C. Boston, I. Burrows, B. Cederwall, M. Ciemala, J. Collado, F. Crespi, D. Cullen, H.J. Eberth, J. Goupil, L. Harkness, H. Hess, A. Jungclaus, W. Korten, M. Labiche, R. Menegazzo, D. Mengoni, B. Million, J. Nyberg, Zs. Podolyák, A. Pullia, B. Quintana Arnés, F. Recchia, P. Reiter, F. Saillant, M.D. Salsac, E. Sanchis, C. Theisen, J.J. Valiente Dobon, and O. Wieland

Subjects
Physics, QC1-999
Abstract

A lifetime measurement of the 19/2− state in 207Pb has been performed using the Recoil Distance Doppler-Shift (RDDS) method. The nuclei of interest were produced in multi-nucleon transfer reactions induced by a 208Pb beam impinging on a 100Mo enriched target. The beam-like nuclei were detected and identified in terms of their atomic mass number in the VAMOS++ spectrometer while the prompt γ rays were detected by the AGATA tracking array. The measured large reduced transition probability B(E3,19/2−→13/2+)=40(8) W.u. is the first indication of the octupole phonon at high spin in 207Pb. An analysis in terms of a particle-octupole-vibration coupling model indicates that the measured B(E3) value in 207Pb is compatible with the contributions from single-phonon and single particle E3 as well as E3 strength arising from the double-octupole-phonon 6+ state, all adding coherently. A crucial aspect of the coupling model, namely the strong mixing between single-hole and the phonon-hole states, is confirmed in a realistic shell-model calculation. Keywords: AGATA spectrometer, γ-Ray tracking, VAMOS++ spectrometer, Plunger device, Nuclear deformation, Octupole phonon

Published
2019
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24. Neutron-rich nuclei produced at zero degrees in damped collisions induced by a beam of 18O on a 238U target

Author

I. Stefan, B. Fornal, S. Leoni, F. Azaiez, C. Portail, J.C. Thomas, A.V. Karpov, D. Ackermann, P. Bednarczyk, Y. Blumenfeld, S. Calinescu, A. Chbihi, M. Ciemala, N. Cieplicka-Oryńczak, F.C.L. Crespi, S. Franchoo, F. Hammache, Ł.W. Iskra, B. Jacquot, R.V.F. Janssens, O. Kamalou, T. Lauritsen, M. Lewitowicz, L. Olivier, S.M. Lukyanov, M. Maccormick, A. Maj, P. Marini, I. Matea, M.A. Naumenko, F. de Oliveira Santos, C. Petrone, Yu.E. Penionzhkevich, F. Rotaru, H. Savajols, O. Sorlin, M. Stanoiu, B. Szpak, O.B. Tarasov, and D. Verney

Subjects
Physics, QC1-999
Abstract

Cross sections and corresponding momentum distributions have been measured for the first time at zero degrees for the exotic nuclei obtained from a beam of 18O at 8.5 MeV/A impinging on a 1 mg/cm2 238U target. Sizable cross sections were found for the production of exotic species arising from the neutron transfer and proton removal from the projectile. Comparisons of experimental results with calculations based on deep-inelastic reaction models, taking into account the particle evaporation process, indicate that zero degree is a scattering angle at which the differential reaction cross section for production of exotic nuclei is at its maximum. This result is important in view of the new generation of zero degrees spectrometers under construction, such as the S3 separator at GANIL, for example. Keywords: Nuclear reactions, Deep-inelastic collisions, Exotic nuclei

Published
2018
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25. Neutron-driven collectivity in light tin isotopes: Proton inelastic scattering from 104Sn

Author

A. Corsi, S. Boissinot, A. Obertelli, P. Doornenbal, M. Dupuis, F. Lechaftois, M. Matsushita, S. Péru, S. Takeuchi, H. Wang, N. Aoi, H. Baba, P. Bednarczyk, M. Ciemala, A. Gillibert, T. Isobe, A. Jungclaus, V. Lapoux, J. Lee, M. Martini, K. Matsui, T. Motobayashi, D. Nishimura, S. Ota, E. Pollacco, H. Sakurai, C. Santamaria, Y. Shiga, D. Sohler, D. Steppenbeck, and R. Taniuchi

Subjects
Physics, QC1-999
Abstract

Inelastic scattering cross sections to individual bound excited states of 104Sn were measured at 150 MeV/u beam energy and analyzed to evaluate the contribution of neutron and proton collectivity. State-of-the-art Quasi-Particle Random Phase Approximation (QRPA) with the D1M Gogny interaction reproduces the experimental proton collectivity and our inelastic scattering cross sections once used as input for a reaction calculation together with the Jeukenne–Lejeune–Mahaux (JLM) potentials. Experimental inelastic scattering cross section decreases by 40(24)% from 112Sn to 104Sn. The present work shows that (i) proton and neutron collectivities are proportional over a large range of tin isotopes (including 104Sn), as is typical for isoscalar excitations, and (ii) the neutron collectivity dominates. It suggests that the plateau in the mass range A=106–112 displayed by E2 transition probabilities is driven by neutron collectivity. Keywords: Collectivity, Inelastic scattering, Gamma spectroscopy

Published
2015
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26. Pygmy dipole resonance in 124Sn populated by inelastic scattering of 17O

Author

L. Pellegri, A. Bracco, F.C.L. Crespi, S. Leoni, F. Camera, E.G. Lanza, M. Kmiecik, A. Maj, R. Avigo, G. Benzoni, N. Blasi, C. Boiano, S. Bottoni, S. Brambilla, S. Ceruti, A. Giaz, B. Million, A.I. Morales, R. Nicolini, V. Vandone, O. Wieland, D. Bazzacco, P. Bednarczyk, M. Bellato, B. Birkenbach, D. Bortolato, B. Cederwall, L. Charles, M. Ciemala, G. De Angelis, P. Désesquelles, J. Eberth, E. Farnea, A. Gadea, R. Gernhäuser, A. Görgen, A. Gottardo, J. Grebosz, H. Hess, R. Isocrate, J. Jolie, D. Judson, A. Jungclaus, N. Karkour, M. Krzysiek, E. Litvinova, S. Lunardi, K. Mazurek, D. Mengoni, C. Michelagnoli, R. Menegazzo, P. Molini, D.R. Napoli, A. Pullia, B. Quintana, F. Recchia, P. Reiter, M.D. Salsac, B. Siebeck, S. Siem, J. Simpson, P.-A. Söderström, O. Stezowski, Ch. Theisen, C. Ur, J.J. Valiente Dobon, and M. Zieblinski

Subjects
Physics, QC1-999
Abstract

The γ decay from the high-lying states of 124Sn was measured using the inelastic scattering of 17O at 340 MeV. The emitted γ rays were detected with high resolution with the AGATA demonstrator array and the scattered ions were detected in two segmented ΔE–E silicon telescopes. The angular distribution was measured both for the γ rays and the scattered 17O ions. An accumulation of E1 strength below the particle threshold was found and compared with previous data obtained with (γ,γ′) and (α,α′γ) reactions. The present results of elastic scattering, and excitation of E2 and E1 states were analysed using the DWBA approach. From this comprehensive description the isoscalar component of the 1− excited states was extracted. The obtained values are based on the comparison of the data with DWBA calculations including a form factor deduced using a microscopic transition density. Keywords: Low-lying electric dipole excitations, 124Sn, Isospin character

Published
2014
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28. High-Precision Spectroscopy of ^{20}O Benchmarking Ab Initio Calculations in Light Nuclei.

Author

Zanon I, Clément E, Goasduff A, Menéndez J, Miyagi T, Assié M, Ciemała M, Flavigny F, Lemasson A, Matta A, Ramos D, Rejmund M, Achouri L, Ackermann D, Barrientos D, Beaumel D, Benzoni G, Boston AJ, Boston HC, Bottoni S, Bracco A, Brugnara D, de France G, de Sereville N, Delaunay F, Desesquelles P, Didierjean F, Domingo-Prato C, Dudouet J, Eberth J, Fernández D, Fougères C, Gadea A, Galtarossa F, Girard-Alcindor V, Gonzales V, Gottardo A, Hammache F, Harkness-Brennan LJ, Hess H, Judson DS, Jungclaus A, Kaşkaş A, Kim YH, Kuşoğlu A, Labiche M, Leblond S, Lenain C, Lenzi SM, Leoni S, Li H, Ljungvall J, Lois-Fuentes J, Lopez-Martens A, Maj A, Menegazzo R, Mengoni D, Michelagnoli C, Million B, Napoli DR, Nyberg J, Pasqualato G, Podolyak Z, Pullia A, Quintana B, Recchia F, Regueira-Castro D, Reiter P, Rezynkina K, Rojo JS, Salsac MD, Sanchis E, Şenyiğit M, Siciliano M, Sohler D, Stezowski O, Theisen C, Utepov A, Valiente-Dobón JJ, Verney D, and Zielinska M

Abstract

The excited states of unstable ^{20}O were investigated via γ-ray spectroscopy following the ^{19}O(d,p)^{20}O reaction at 8  AMeV. By exploiting the Doppler shift attenuation method, the lifetimes of the 2_{2}^{+} and 3_{1}^{+} states were firmly established. From the γ-ray branching and E2/M1 mixing ratios for transitions deexciting the 2_{2}^{+} and 3_{1}^{+} states, the B(E2) and B(M1) were determined. Various chiral effective field theory Hamiltonians, describing the nuclear properties beyond ground states, along with a standard USDB interaction, were compared with the experimentally obtained data. Such a comparison for a large set of γ-ray transition probabilities with the valence space in medium similarity renormalization group ab initio calculations was performed for the first time in a nucleus far from stability. It was shown that the ab initio approaches using chiral effective field theory forces are challenged by detailed high-precision spectroscopic properties of nuclei. The reduced transition probabilities were found to be a very constraining test of the performance of the ab initio models.

Published
2023
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29. Shape Coexistence at Zero Spin in ^{64}Ni Driven by the Monopole Tensor Interaction.

Author

Mărginean N, Little D, Tsunoda Y, Leoni S, Janssens RVF, Fornal B, Otsuka T, Michelagnoli C, Stan L, Crespi FCL, Costache C, Lica R, Sferrazza M, Turturica A, Ayangeakaa AD, Auranen K, Barani M, Bender PC, Bottoni S, Boromiza M, Bracco A, Călinescu S, Campbell CM, Carpenter MP, Chowdhury P, Ciemała M, Cieplicka-Oryǹczak N, Cline D, Clisu C, Crawford HL, Dinescu IE, Dudouet J, Filipescu D, Florea N, Forney AM, Fracassetti S, Gade A, Gheorghe I, Hayes AB, Harca I, Henderson J, Ionescu A, Iskra ŁW, Jentschel M, Kandzia F, Kim YH, Kondev FG, Korschinek G, Köster U, Krishichayan, Krzysiek M, Lauritsen T, Li J, Mărginean R, Maugeri EA, Mihai C, Mihai RE, Mitu A, Mutti P, Negret A, Niţă CR, Olăcel A, Oprea A, Pascu S, Petrone C, Porzio C, Rhodes D, Seweryniak D, Schumann D, Sotty C, Stolze SM, Şuvăilă R, Toma S, Ujeniuc S, Walters WB, Wu CY, Wu J, Zhu S, and Ziliani S

Abstract

The low-spin structure of the semimagic ^{64}Ni nucleus has been considerably expanded: combining four experiments, several 0^{+} and 2^{+} excited states were identified below 4.5 MeV, and their properties established. The Monte Carlo shell model accounts for the results and unveils an unexpectedly complex landscape of coexisting shapes: a prolate 0^{+} excitation is located at a surprisingly high energy (3463 keV), with a collective 2^{+} state 286 keV above it, the first such observation in Ni isotopes. The evolution in excitation energy of the prolate minimum across the neutron N=40 subshell gap highlights the impact of the monopole interaction and its variation in strength with N.

Published
2020
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30. Superdeformed and Triaxial States in ^{42}Ca.

Author

Hadyńska-Klȩk K, Napiorkowski PJ, Zielińska M, Srebrny J, Maj A, Azaiez F, Valiente Dobón JJ, Kicińska-Habior M, Nowacki F, Naïdja H, Bounthong B, Rodríguez TR, de Angelis G, Abraham T, Anil Kumar G, Bazzacco D, Bellato M, Bortolato D, Bednarczyk P, Benzoni G, Berti L, Birkenbach B, Bruyneel B, Brambilla S, Camera F, Chavas J, Cederwall B, Charles L, Ciemała M, Cocconi P, Coleman-Smith P, Colombo A, Corsi A, Crespi FC, Cullen DM, Czermak A, Désesquelles P, Doherty DT, Dulny B, Eberth J, Farnea E, Fornal B, Franchoo S, Gadea A, Giaz A, Gottardo A, Grave X, Grȩbosz J, Görgen A, Gulmini M, Habermann T, Hess H, Isocrate R, Iwanicki J, Jaworski G, Judson DS, Jungclaus A, Karkour N, Kmiecik M, Karpiński D, Kisieliński M, Kondratyev N, Korichi A, Komorowska M, Kowalczyk M, Korten W, Krzysiek M, Lehaut G, Leoni S, Ljungvall J, Lopez-Martens A, Lunardi S, Maron G, Mazurek K, Menegazzo R, Mengoni D, Merchán E, Mȩczyński W, Michelagnoli C, Mierzejewski J, Million B, Myalski S, Napoli DR, Nicolini R, Niikura M, Obertelli A, Özmen SF, Palacz M, Próchniak L, Pullia A, Quintana B, Rampazzo G, Recchia F, Redon N, Reiter P, Rosso D, Rusek K, Sahin E, Salsac MD, Söderström PA, Stefan I, Stézowski O, Styczeń J, Theisen Ch, Toniolo N, Ur CA, Vandone V, Wadsworth R, Wasilewska B, Wiens A, Wood JL, Wrzosek-Lipska K, and Ziȩbliński M

Abstract

Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in ^{42}Ca were determined from E2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 0_{2}^{+} has been obtained and the role of triaxiality in the A∼40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time.

Published
2016
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31. Isospin character of low-lying pygmy dipole states in 208Pb via inelastic scattering of 17O ions.

Author

Crespi FC, Bracco A, Nicolini R, Mengoni D, Pellegri L, Lanza EG, Leoni S, Maj A, Kmiecik M, Avigo R, Benzoni G, Blasi N, Boiano C, Bottoni S, Brambilla S, Camera F, Ceruti S, Giaz A, Million B, Morales AI, Vandone V, Wieland O, Bednarczyk P, Ciemała M, Grebosz J, Krzysiek M, Mazurek K, Zieblinski M, Bazzacco D, Bellato M, Birkenbach B, Bortolato D, Calore E, Cederwall B, Charles L, de Angelis G, Désesquelles P, Eberth J, Farnea E, Gadea A, Görgen A, Gottardo A, Isocrate R, Jolie J, Jungclaus A, Karkour N, Korten W, Menegazzo R, Michelagnoli C, Molini P, Napoli DR, Pullia A, Recchia F, Reiter P, Rosso D, Sahin E, Salsac MD, Siebeck B, Siem S, Simpson J, Söderström PA, Stezowski O, Theisen Ch, Ur C, and Valiente-Dobón JJ

Abstract

The properties of pygmy dipole states in 208Pb were investigated using the 208Pb(17O, 17O'γ) reaction at 340 MeV and measuring the γ decay with high resolution with the AGATA demonstrator array. Cross sections and angular distributions of the emitted γ rays and of the scattered particles were measured. The results are compared with (γ, γ') and (p, p') data. The data analysis with the distorted wave Born approximation approach gives a good description of the elastic scattering and of the inelastic excitation of the 2+ and 3- states. For the dipole transitions a form factor obtained by folding a microscopically calculated transition density was used for the first time. This has allowed us to extract the isoscalar component of the 1- excited states from 4 to 8 MeV.

Published
2014
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