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1. Axial and triaxial degrees of freedom in 72Zn

Author

S. Hellgartner, D. Mücher, K. Wimmer, V. Bildstein, J.L. Egido, R. Gernhäuser, R. Krücken, A.K. Nowak, M. Zielińska, C. Bauer, M.L.L. Benito, S. Bottoni, H. De Witte, J. Elseviers, D. Fedorov, F. Flavigny, A. Illana, M. Klintefjord, T. Kröll, R. Lutter, B. Marsh, R. Orlandi, J. Pakarinen, R. Raabe, E. Rapisarda, S. Reichert, P. Reiter, M. Scheck, M. Seidlitz, B. Siebeck, E. Siesling, T. Steinbach, T. Stora, M. Vermeulen, D. Voulot, N. Warr, and F.J.C. Wenander

Subjects
Multiple Coulomb excitation, 72Zn, N=40 sub-shell closure, Triaxiality, Physics, QC1-999
Abstract

The unstable N=42 nucleus 72Zn has been studied using multiple safe Coulomb excitation in inverse kinematics. The experiment was performed at the REX-ISOLDE facility at CERN making first use of the silicon detector array C-REX in combination with the γ-ray spectrometer Miniball. The high angular coverage of C-REX allowed to determine the reduced transition strengths for the decay of the yrast 01+, 21+ and 41+ as well as of the 02+ and 22+ states in 72Zn. The quadrupole moments of the 21+, 41+ and 22+ states were extracted. Using model independent quadrupole invariants, the ground state of 72Zn was found to have an average deformation in the γ degree of freedom close to maximum triaxiality. In comparison to experimental data in zinc isotopes with N

Published
2023
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2. Addendum: The observation of vibrating pear-shapes in radon nuclei

Author

P. A. Butler, L. P. Gaffney, P. Spagnoletti, J. Konki, M. Scheck, J. F. Smith, K. Abrahams, M. Bowry, J. Cederkäll, T. Chupp, G. de Angelis, H. De Witte, P. E. Garrett, A. Goldkuhle, C. Henrich, A. Illana, K. Johnston, D. T. Joss, J. M. Keatings, N. A. Kelly, M. Komorowska, T. Kröll, M. Lozano, B. S. Nara Singh, D. O’Donnell, J. Ojala, R. D. Page, L. G. Pedersen, C. Raison, P. Reiter, J. A. Rodriguez, D. Rosiak, S. Rothe, T. M. Shneidman, B. Siebeck, M. Seidlitz, J. Sinclair, M. Stryjczyk, P. Van Duppen, S. Vinals, V. Virtanen, N. Warr, K. Wrzosek-Lipska, and M. Zielinska

Subjects
Science
Published
2020
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3. Enhanced quadrupole collectivity in doubly-magic 56Ni: Lifetime measurements of the 41+ and 61+ states

Author

K. Arnswald, A. Blazhev, F. Nowacki, P. Petkov, P. Reiter, T. Braunroth, A. Dewald, M. Droste, C. Fransen, R. Hirsch, V. Karayonchev, L. Kaya, L. Lewandowski, C. Müller-Gatermann, M. Seidlitz, B. Siebeck, A. Vogt, D. Werner, and K.O. Zell

Subjects
Doubly-magic nuclei, N=Z nuclei, Lifetime measurements, DSAM, B(E2) values, Physics, QC1-999
Abstract

Lifetime measurements of excited states in doubly-magic 56Ni have been performed exploiting the Doppler-shift attenuation method in order to determine reduced transition probabilities. For the 41+ and 61+ states, the deduced B(E2) values are compared with results from shell-model calculations employing the GXPF1A and the modern PFSDG-U interactions. In addition, valence ab-initio calculations were performed using a novel realistic Hamiltonian derived from chiral perturbation theory including three-body potential contributions and are confronted with the experimental findings. The new results show maximum E2 strength in comparison with known values along the N=28 chain of isotones. The results corroborate the high collectivity for the double shell closure at N=Z=28 which was anticipated from the large B(E2;21+→0g.s.+) value despite the considerable increase of its excitation energy as compared to neighboring semi-magic nuclei. Based on similarities in the shell structures of the self-conjugate doubly-magic nuclei 56Ni and 100Sn, the new values could be an indication for an expected comparable collective behavior of the 61+ state in 100Sn.

Published
2021
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4. The observation of vibrating pear-shapes in radon nuclei

Author

P. A. Butler, L. P. Gaffney, P. Spagnoletti, J. Konki, M. Scheck, J. F. Smith, K. Abrahams, M. Bowry, J. Cederkäll, T. Chupp, G. de Angelis, H. De Witte, P. E. Garrett, A. Goldkuhle, C. Henrich, A. Illana, K. Johnston, D. T. Joss, J. M. Keatings, N. A. Kelly, M. Komorowska, T. Kröll, M. Lozano, B. S. Nara Singh, D. O’Donnell, J. Ojala, R. D. Page, L. G. Pedersen, C. Raison, P. Reiter, J. A. Rodriguez, D. Rosiak, S. Rothe, T. M. Shneidman, B. Siebeck, M. Seidlitz, J. Sinclair, M. Stryjczyk, P. Van Duppen, S. Vinals, V. Virtanen, N. Warr, K. Wrzosek-Lipska, and M. Zielinska

Subjects
Science
Abstract

Octupole deformation in nuclei is important to understand nuclear structure and electric dipole moments of heavy atoms. Here the authors measure energies of excited quantum states in radon isotopes and find that these isotopes do not provide favourable conditions in the search for CP-violation.

Published
2019
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5. Enhanced collectivity along the N=Z line: Lifetime measurements in 44Ti, 48Cr, and 52Fe

Author

K. Arnswald, T. Braunroth, M. Seidlitz, L. Coraggio, P. Reiter, B. Birkenbach, A. Blazhev, A. Dewald, C. Fransen, B. Fu, A. Gargano, H. Hess, R. Hirsch, N. Itaco, S.M. Lenzi, L. Lewandowski, J. Litzinger, C. Müller-Gatermann, M. Queiser, D. Rosiak, D. Schneiders, B. Siebeck, T. Steinbach, A. Vogt, K. Wolf, and K.O. Zell

Subjects
N=Z nuclei, Lifetime measurements, RDDS, B(E2) values, Physics, QC1-999
Abstract

Lifetimes of the 21+ states in 44Ti, 48,50Cr, and 52Fe were determined with high accuracy exploiting the recoil distance Doppler-shift method. The reduced E2 transition strengths of 44Ti and 52Fe differ considerably from previously known values. A systematic increase in collectivity is found for the N=Z nuclei compared to neighboring isotopes. The B(E2) values along the Ti, Cr, and Fe isotopic chains are compared to shell-model calculations employing established interactions for the 0f1p shell, as well as a novel effective shell-model Hamiltonian starting from a realistic nucleon–nucleon potential. The theoretical approaches underestimate the B(E2) values for the lower-mass Ti isotopes. Strong indication is found for particle-hole cross-shell configurations, recently corroborated by similar results for the neighboring isotone 42Ca.

Published
2017
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6. Publisher Correction: The observation of vibrating pear-shapes in radon nuclei

Author

P. A. Butler, L. P. Gaffney, P. Spagnoletti, J. Konki, M. Scheck, J. F. Smith, K. Abrahams, M. Bowry, J. Cederkäll, T. Chupp, G. de Angelis, H. De Witte, P. E. Garrett, A. Goldkuhle, C. Henrich, A. Illana, K. Johnston, D. T. Joss, J. M. Keatings, N. A. Kelly, M. Komorowska, T. Kröll, M. Lozano, B. S. Nara Singh, D. O’Donnell, J. Ojala, R. D. Page, L. G. Pedersen, C. Raison, P. Reiter, J. A. Rodriguez, D. Rosiak, S. Rothe, T. M. Shneidman, B. Siebeck, M. Seidlitz, J. Sinclair, M. Stryjczyk, P. Van Duppen, S. Vinals, V. Virtanen, N. Warr, K. Wrzosek-Lipska, and M. Zielinska

Subjects
Science
Abstract

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Published
2020
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7. Axial and triaxial degrees of freedom in $^{72}$Zn

Author

S. Hellgartner, D. Mücher, K. Wimmer, V. Bildstein, J.L. Egido, R. Gernhäuser, R. Krücken, A.K. Nowak, M. Zielińska, C. Bauer, M.L.L. Benito, S. Bottoni, H. De Witte, J. Elseviers, D. Fedorov, F. Flavigny, A. Illana, M. Klintefjord, T. Kröll, R. Lutter, B. Marsh, R. Orlandi, J. Pakarinen, R. Raabe, E. Rapisarda, S. Reichert, P. Reiter, M. Scheck, M. Seidlitz, B. Siebeck, E. Siesling, T. Steinbach, T. Stora, M. Vermeulen, D. Voulot, N. Warr, F.J.C. Wenander, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Triaxiality, Molecular, Atomic, Nuclear & Particles Physics, Particle and Plasma Physics, Nuclear Physics - Theory, Zn, Nuclear, Multiple Coulomb excitation, sub-shell closure, Mathematical Physics, Astronomical and Space Sciences
Abstract

International audience; The unstable N=42 nucleus 72Zn has been studied using multiple safe Coulomb excitation in inverse kinematics. The experiment was performed at the REX-ISOLDE facility at CERN making first use of the silicon detector array C-REX in combination with the γ-ray spectrometer Miniball. The high angular coverage of C-REX allowed to determine the reduced transition strengths for the decay of the yrast 01+, 21+ and 41+ as well as of the 02+ and 22+ states in 72Zn. The quadrupole moments of the 21+, 41+ and 22+ states were extracted. Using model independent quadrupole invariants, the ground state of 72Zn was found to have an average deformation in the γ degree of freedom close to maximum triaxiality. In comparison to experimental data in zinc isotopes with N<40, the collectivity of the 41+ state in neutron-rich 72Zn is significantly larger, indicating a collective yrast band based on the ground state of 72Zn. In contrast, a low experimental B(E2;02+→21+) strength was determined, indicating a different structure for the 02+ state. Shell-model calculations propose a 02+ state featuring a larger fraction of the (spherical) N=40 closed-shell configuration in its wave function than for the 01+ ground state. The results were also compared with beyond mean field calculations which corroborate the large deformation in the γ degree of freedom, while pointing to a more deformed 02+ state. These experimental and theoretical findings establish the importance of the γ degree of freedom in the ground state of 72Zn, located between the 68,70Ni nuclei that have spherical ground states, and 76Ge, which has a rigid triaxial shape.

Published
2023
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9. Lifetime measurements in Ti44

Author

B. Siebeck, D. Werner, P. Reiter, M. Seidlitz, C. Fransen, K. Wolf, A. Dewald, K. O. Zell, D. Rosiak, L. Lewandowski, A. Vogt, L. Kaya, Thomas Braunroth, R. Hirsch, C. Müller-Gatermann, A. Blazhev, R. Hetzenegger, A. Goldkuhle, K. Arnswald, M. Droste, P. Petkov, and E. Hoemann

Subjects
Physics, symbols.namesake, Recoil, 010308 nuclear & particles physics, Excited state, 0103 physical sciences, symbols, Atomic physics, 010306 general physics, Hamiltonian (quantum mechanics), 01 natural sciences
Abstract

Lifetimes of excited nuclear states were determined in $^{44}\mathrm{Ti}$ using the recoil distance Doppler-shift technique and the Doppler-shift attenuation method. Results from the ${K}^{\ensuremath{\pi}}={3}^{\ensuremath{-}}$ band confirm isospin-symmetry breaking for the ${3}_{1}^{\ensuremath{-}}\ensuremath{\rightarrow}{2}_{1}^{+}\phantom{\rule{4pt}{0ex}}E1$ transition. The lifetime of the ${4}_{1}^{\ensuremath{-}}$ state differs considerably from the previously known value. Good agreement is found for the ${4}_{1}^{+}$ and ${6}_{1}^{+}$ level lifetimes with respect to previous values. The experimental values are compared with large-scale shell-model calculations employing established interactions in the $0f1p$ shell, as well as a modern effective Hamiltonian including multiparticle multihole cross-shell configurations. Extended configuration spaces of this shell-model calculation allow for a detailed comparison with newly determined negative-parity states.

Published
2020
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10. The observation of vibrating pear-shapes in radon nuclei

Author

M. Zielińska, L. G. Pedersen, M. Bowry, N. Warr, M. Seidlitz, Liam Gaffney, P. E. Garrett, M. Lozano, A. Illana, D. Rosiak, V. Virtanen, R. D. Page, J. M. Keatings, P. Reiter, M. Stryjczyk, K. Wrzosek-Lipska, B. Siebeck, N. A. Kelly, D. T. Joss, H. De Witte, David O'Donnell, P. Van Duppen, J. Sinclair, K. Abrahams, S. Vinals, Sebastian Rothe, C. Raison, J. Ojala, M. Komorowska, B. S. Nara Singh, P. A. Butler, T.M. Shneidman, C. Henrich, A. Goldkuhle, J. Cederkäll, Timothy Chupp, J. Konki, Jose Rodriguez, P. Spagnoletti, J. F. Smith, G. de Angelis, Karl Johnston, Marcus Scheck, T. Kröll, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Science and Technology Facilities Council (UK), Federal Ministry of Education and Research (Germany), National Science Centre (Poland), European Commission, Research Foundation - Flanders, Belgian Science Policy Office, Russian Foundation for Basic Research, and SCOAP

Subjects
Physics beyond the Standard Model, Science, Nuclear Theory, General Physics and Astronomy, chemistry.chemical_element, Radon, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, Radium, Quantum state, 0103 physical sciences, CP: violation, ground state, Nuclear Physics - Experiment, Physics::Atomic Physics, Experimental nuclear physics, lcsh:Science, 010306 general physics, numerical calculations, Nuclear Experiment, Physics, Multidisciplinary, Isotope, 010308 nuclear & particles physics, new physics, nucleus, radon, General Chemistry, Publisher Correction, radium, exotic nuclei, electric moment, chemistry, radioactivity, Moment (physics), Atomic nucleus, CP violation, lcsh:Q, Exotic atoms and molecules, Atomic physics, ydinfysiikka
Abstract

6 pags., 4 fig.s, 1 tab. -- Open Access funded by Creative Commons Atribution Licence 4.0, There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we observed the low-lying quantum states in Rn and Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment., The support of the ISOLDE Collaboration and technical teams is acknowledged. This work was supported by the following Research Councils and Grants: Science and Technology Facilities Council (STFC; UK) grants ST/ P004598/1, ST/L005808/1; Federal Ministry of Education and Research (BMBF; Germany) grants 05P18RDCIA, 05P15PKCIA and 05P18PKCIA and the “Verbundprojekt 05P2018”; National Science Centre (Poland) grant 2015/18/M/ST2/00523; European Union’s Horizon 2020 Framework research and innovation programme 654002 (ENSAR2); Marie Skłodowska-Curie COFUND grant (EU-CERN) 665779; Research Foundation Flanders (FWO, Belgium), by GOA/2015/010 (BOF KU Leuven) and the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12); RFBR(Russia) grant 17-52-12015.

Published
2020
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11. Enhanced quadrupole collectivity in doubly-magic 56Ni: Lifetime measurements of the 41+ and 61+ states

Author

C. Fransen, V. Karayonchev, D. Werner, L. Kaya, A. Vogt, M. Droste, A. Blazhev, F. Nowacki, R. Hirsch, P. Reiter, A. Dewald, K. Arnswald, C. Müller-Gatermann, B. Siebeck, Thomas Braunroth, L. Lewandowski, M. Seidlitz, P. Petkov, and K. O. Zell

Subjects
Physics, Nuclear and High Energy Physics, Collective behavior, Chiral perturbation theory, Valence (chemistry), 010308 nuclear & particles physics, Shell (structure), 01 natural sciences, symbols.namesake, Excited state, 0103 physical sciences, Quadrupole, symbols, Atomic physics, 010306 general physics, Hamiltonian (quantum mechanics), Excitation
Abstract

Lifetime measurements of excited states in doubly-magic 56Ni have been performed exploiting the Doppler-shift attenuation method in order to determine reduced transition probabilities. For the 4 1 + and 6 1 + states, the deduced B ( E2 ) values are compared with results from shell-model calculations employing the GXPF1A and the modern PFSDG-U interactions. In addition, valence ab-initio calculations were performed using a novel realistic Hamiltonian derived from chiral perturbation theory including three-body potential contributions and are confronted with the experimental findings. The new results show maximum E2 strength in comparison with known values along the N = 28 chain of isotones. The results corroborate the high collectivity for the double shell closure at N = Z = 28 which was anticipated from the large B ( E2 ; 2 1 + → 0 g . s . + ) value despite the considerable increase of its excitation energy as compared to neighboring semi-magic nuclei. Based on similarities in the shell structures of the self-conjugate doubly-magic nuclei 56Ni and 100Sn, the new values could be an indication for an expected comparable collective behavior of the 6 1 + state in 100Sn.

Published
2021
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12. Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive Ra222 and Ra228 Beams

Author

J. Sinclair, Joonas Konki, M. Lozano, A. Illana, D. T. Joss, S. Vinals, Robert Page, Th. Kröll, A. Goldkuhle, K. Wrzosek-Lipska, D. Rosiak, Liam Gaffney, M. Zielińska, V. Virtanen, P. Van Duppen, P. E. Garrett, K. Abrahams, H. De Witte, T.M. Shneidman, J. Ojala, P. Reiter, David O'Donnell, Mike Bowry, P. Spagnoletti, N. Warr, M. Seidlitz, M. Stryjczyk, B. Siebeck, P. A. Butler, Marcus Scheck, Karl Johnston, M. Komorowska, J. F. Smith, L. G. Pedersen, J. M. Keatings, Joakim Cederkäll, G. de Angelis, C. Henrich, B. S. Nara Singh, N. A. Kelly, Sebastian Rothe, C. Raison, and Jose Rodriguez

Subjects
Physics, Isotope, Nuclear Theory, General Physics and Astronomy, chemistry.chemical_element, Coulomb excitation, 01 natural sciences, Radium, Matrix (mathematics), chemistry, Excited state, 0103 physical sciences, Atomic nucleus, Coulomb, Physics::Accelerator Physics, Physics::Atomic Physics, Atomic physics, Deformation (engineering), Nuclear Experiment, 010306 general physics
Abstract

There is sparse direct experimental evidence that atomic nuclei can exhibit stable "pear" shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole (E3) matrix elements have been determined for transitions in ^{222,228}Ra nuclei using the method of sub-barrier, multistep Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of E3 matrix elements for different nuclear transitions is explained by describing ^{222}Ra as pear shaped with stable octupole deformation, while ^{228}Ra behaves like an octupole vibrator.

Published
2020
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13. Search for proton emission of the isomeric $$\mathbf {10^+}$$ state in $$\mathbf {^{54}}$$Ni

Author

Robert Hoischen, J. Eberth, Anna Wendt, Claes Fahlander, P. Reiter, C. Fransen, Pavel Golubev, D. Lersch, M. Seidlitz, A. Holler, Jan Taprogge, T. Kotthaus, A. Blazhev, Andreas Wiens, Herbert Hess, B. Siebeck, Gheorghe Pascovici, O. Zell, N. Warr, Dirk Rudolph, B. Bruyneel, K. Stahl, and M. Kalkühler

Subjects
Physics, Nuclear and High Energy Physics, education.field_of_study, 010308 nuclear & particles physics, Population, Hadron, Nuclear structure, State (functional analysis), 01 natural sciences, 0103 physical sciences, Nuclear fusion, Atomic physics, Proton emission, 010306 general physics, education, Beam energy, Excitation
Abstract

Several experiments were conducted at the 10 MV Van-de-Graaff tandem accelerator at the Institute of Nuclear Physics, Cologne, to detect proton emission from the isomeric 6457-keV $$10^+$$10+ state in $$^{54}\hbox {Ni}$$54Ni. Excitation functions for two fusion–evaporation reactions were measured to maximise the population of the rare two-neutron evaporation channel from a $$^{56}\hbox {Ni}$$56Ni compound nucleus. The search for delayed proton emission was based on the $$^{28}\hbox {Si}$$28Si($$^{28}\hbox {Si},2n$$28Si,2n)$$^{54}\hbox {Ni}$$54Ni reaction at a beam energy of 70 MeV. For this reaction, a cross-section limit for the population of the $$10^+$$10+ state in $$^{54}\hbox {Ni}$$54Ni and its proton-decay branch was determined to be $$\sigma < 22$$σ<22 nb.

Published
2020
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14. Addendum: The observation of vibrating pear-shapes in radon nuclei

Author

T.M. Shneidman, P. E. Garrett, Jose Rodriguez, H. De Witte, David O'Donnell, M. Stryjczyk, D. Rosiak, Timothy Chupp, Th. Kröll, P. Reiter, B. Siebeck, J. Sinclair, P. Spagnoletti, J. F. Smith, V. Virtanen, Karl Johnston, N. A. Kelly, J. M. Keatings, Marcus Scheck, Liam Gaffney, C. Raison, Joonas Konki, L. G. Pedersen, K. Wrzosek-Lipska, M. Lozano, G. de Angelis, A. Illana, J. Ojala, Sebastian Rothe, Robert Page, Joakim Cederkäll, D. T. Joss, M. Zielińska, P. Van Duppen, M. Komorowska, M. Seidlitz, K. Abrahams, A. Goldkuhle, M. Bowry, P. A. Butler, N. Warr, S. Vinals, C. Henrich, and B. S. Nara Singh

Subjects
0301 basic medicine, PEAR, Multidisciplinary, Science, General Physics and Astronomy, chemistry.chemical_element, Addendum, Radon, 02 engineering and technology, General Chemistry, 021001 nanoscience & nanotechnology, Archaeology, General Biochemistry, Genetics and Molecular Biology, 03 medical and health sciences, 030104 developmental biology, chemistry, lcsh:Q, Exotic atoms and molecules, Experimental nuclear physics, lcsh:Science, 0210 nano-technology, Geology
Abstract

5 pags., 4 figs., 1 tab. -- Addendum to: Nature Communications https://doi.org/10.1038/s41467-019-10494-5, published online 6 June 2019.

Published
2020

15. Isomer spectroscopy in Ba133 and high-spin structure of Ba134

Author

E. Farnea, H. K. Wang, C. Fransen, K. Schomacker, A. Gadea, W. Korten, P. Reiter, N. Saed-Samii, A. Jungclaus, L. Corradi, A. Vogt, Hans-Jurgen E. Hess, L. Kaya, K. O. Zell, Suzana Szilner, O. Stezowski, A. Blazhev, J. Eberth, A. Bracco, G. Pollarolo, V. Karayonchev, E. Teruya, B. Birkenbach, A. Esmaylzadeh, T. Mijatović, M. Droste, A. M. Stefanini, N. Shimizu, B. Bruyneel, E. Fioretto, Nunzio Itaco, A. Giaz, Yutaka Utsuno, A. Gottardo, L. Kornwebel, F. Recchia, Zs. Podolyák, F. Scarlassara, R. Menegazzo, S. Leoni, L. Coraggio, A. Gargano, G. Montagnoli, R. Hirsch, F. C. L. Crespi, K. Arnswald, J. Jolie, D. Bazzacco, L. Lewandowski, D. Mengoni, J.-M. Régis, C. Michelagnoli, K. Yanase, E. Sahin, D. R. Napoli, C. Müller-Gatermann, K. Wolf, B. Siebeck, C. A. Ur, K. Hadynska-Klek, M. Seidlitz, S. Lunardi, D. Montanari, M. Siciliano, B. Szpak, G. de Angelis, Andreas Görgen, P. R. John, J. J. Valiente-Dobón, Naotaka Yoshinaga, and P. A. Söderström

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Yrast, 0103 physical sciences, Tandem accelerator, Atomic physics, Spin structure, 010306 general physics, Spectroscopy, 7. Clean energy, 01 natural sciences
Abstract

The transitional nuclei $^{134}$Ba and $^{133}$Ba are investigated after multinucleon transfer employing the high-resolution Advanced GAmma Tracking Array coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and after fusion-evaporation reaction at the FN tandem accelerator of the University of Cologne, Germany. The Jπ=19/2+ state at 1942 keV in $^{133}$Ba is identified as an isomer with a half-life of 66.6(20)ns corresponding to a B(E1) value of 7.7(4)×10−6e2fm2 for the Jπ=19/2+ to Jπ=19/2− transition. The level scheme of $^{134}$Ba above the Jπ=10+ isomer is extended to approximately 6 MeV. A pronounced backbending is observed at ℏω=0.38 MeV along the positive-parity yrast band. The results are compared to the high-spin systematics of the Z=56 isotopes. Large-scale shell-model calculations employing the GCN50:82, SN100PN, SNV, PQM130, Realistic SM, and EPQQM interactions reproduce the experimental findings and elucidate the structure of the high-spin states. The shell-model calculations employing the GCN50:82 and PQM130 interactions reproduce alignment properties and provide detailed insight into the microscopic origin of this phenomenon in transitional $^{134}$Ba.

Published
2019
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16. Microscopic structure of coexisting 0+ states in Ni68 probed via two-neutron transfer

Author

C. Bauer, A. N. Andreyev, S. Klupp, P. Reiter, J. Elseviers, F. Flavigny, R. Lutter, T. Roger, Roman Gernhäuser, Kathrin Wimmer, V. Bildstein, B. A. Marsh, N. Patronis, F. Recchia, D. Voulot, S. Sambi, S. Ilieva, F. Wenander, Jan Diriken, Th. Kröll, A. Blazhev, R. Raabe, K. Nowak, B. Siebeck, M. D. Seliverstov, Marc Huyse, B. A. Brown, M. J. Vermeulen, Takaharu Otsuka, V. N. Fedosseev, M. von Schmid, M. Seidlitz, S. Franchoo, Janne Pakarinen, P. Van Duppen, N. Warr, H. De Witte, Yusuke Tsunoda, and D. Mücher

Subjects
Physics, Ion beam, 010308 nuclear & particles physics, Nuclear structure, State (functional analysis), 01 natural sciences, Amplitude, Excited state, 0103 physical sciences, Neutron, Atomic physics, Born approximation, 010306 general physics, Ground state
Abstract

The structure of low-spin states originating from shape-coexisting configurations in $^{68}_{40}$Ni$_{28}$ was directly probed via the two-neutron transfer reaction $^{66}$Ni$(t,p)^{68}$Ni in inverse kinematics using a radioactive ion beam on a radioactive target. The direct feeding to the first excited 0$^+$ state was measured for center-of-mass angles 4°–16° and amounts to an integral of 4.2(16)% relative to the ground state. The observed difference in feeding of the 0$^+$ states is explained by the transfer of neutrons, mainly in the $pf$ shell below $N=40$ for the ground state, and across $N=40$ in the $g_{9/2}$ orbital for the 0$_2^+$, based on second-order distorted-wave Born approximation calculations combined with state-of-the-art shell-model two-nucleon amplitudes. However, the direct feeding to the 2$_1^+$ state [29(3)%] is incompatible with these calculations.

Published
2019
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17. Coulomb excitation of pear-shaped nuclei

Author

M. Stryjczyk, P. Reiter, M. Komorowska, M. Lozano, A. Illana, Silvia Vinals, B. Siebeck, Line Pedersen, Michael Bowry, T. Kröll, Marcus Scheck, N. Warr, Liam Gaffney, D. Rosiak, J. Sinclair, M. Zielińska, J. F. Smith, A. Goldkuhle, D. T. Joss, Nicola Kelly, Sebastian Rothe, David O'Donnell, M. Seidlitz, Robert Page, P. A. Butler, Timur Shneidman, Kenzo Abrahams, Bondili Nara Singh, Giacomo de Angelis, V. Virtanen, Karl Johnston, J. M. Keatings, J. Ojala, Joakim Cederkäll, P. E. Garrett, Kasia Wrzosek-Lipska, C. Henrich, Hilde De Witte, Christopher Raison, P. Spagnoletti, Piet Van Duppen, Joonas Konki, Timothy Chupp, Jose Rodriguez, de Angelis, G., Corradi, L., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, DeAngelis, G, and Corradi, L

Subjects
Physics, Isotope, 010308 nuclear & particles physics, QC1-999, Physics beyond the Standard Model, chemistry.chemical_element, Radon, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, chemistry, Quantum state, 0103 physical sciences, Moment (physics), Atomic nucleus, CP violation, Nuclear Physics - Experiment, Physics::Atomic Physics, Atomic physics, 010306 general physics, ydinfysiikka
Abstract

There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we have observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.

Published
2019
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18. Enhanced Quadrupole and Octupole Strength in Doubly Magic Sn132

Author

Marc Huyse, Karl Johnston, Daniel Cox, P. Reiter, A. Vogt, M L Lozano Benito, J. Ojala, A. Blazhev, L. Kaya, Joakim Cederkäll, Jose Rodriguez, H. Naïdja, Tomoaki Togashi, M. Seidlitz, B. Siebeck, T. Berry, A. Illana, K. O. Zell, N. Warr, C. Henrich, F. Wenander, Janne Pakarinen, F. Nowacki, M. Queiser, H. De Witte, J. Snäll, Liam Gaffney, E. Siesling, Hie-Isolde Collaborations, D. Rosiak, Yusuke Tsunoda, María José García Borge, Miniball, G. Rainovski, K. Arnswald, Gianluca Colò, P. Van Duppen, M. von Schmid, Takaharu Otsuka, R. Hirsch, and Th. Kröll

Subjects
Physics, Large Hadron Collider, 010308 nuclear & particles physics, Projectile, Monte Carlo method, General Physics and Astronomy, Coulomb excitation, 01 natural sciences, Ion, Excited state, 0103 physical sciences, Quadrupole, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

The first 2+ and 3- states of the doubly magic nucleus Sn132 are populated via safe Coulomb excitation employing the recently commissioned HIE-ISOLDE accelerator at CERN in conjunction with the highly efficient MINIBALL array. The Sn132 ions are accelerated to an energy of 5.49 MeV/nucleon and impinged on a Pb206 target. Deexciting γ rays from the low-lying excited states of the target and the projectile are recorded in coincidence with scattered particles. The reduced transition strengths are determined for the transitions 0g.s.+→21+, 0g.s.+→31-, and 21+→31- in Sn132. The results on these states provide crucial information on cross-shell configurations which are determined within large-scale shell-model and Monte Carlo shell-model calculations as well as from random-phase approximation and relativistic random-phase approximation. The locally enhanced B(E2;0g.s.+→21+) strength is consistent with the microscopic description of the structure of the respective states within all theoretical approaches. The presented results of experiment and theory can be considered to be the first direct verification of the sphericity and double magicity of Sn132. (Less)

Published
2018
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19. High-spin structure in the transitional nucleus Xe131 : Competitive neutron and proton alignment in the vicinity of the N=82 shell closure

Author

Naotaka Yoshinaga, W. Korten, A. Bracco, E. Fioretto, Agnese Giaz, Koji Higashiyama, C. A. Ur, F. Recchia, A. Vogt, S. Lunardi, J. Jolie, B. Birkenbach, R. Hirsch, D. Montanari, A. Jungclaus, G. Montagnoli, Suzana Szilner, K. Arnswald, O. Stezowski, B. Bruyneel, G. de Angelis, P. Reiter, F. C. L. Crespi, P. R. John, S. Leoni, B. Fu, T. Steinbach, B. Szpak, E. Farnea, L. Coraggio, A. Gargano, N. Saed-Samii, A. Blazhev, A. Gadea, Roberto Menegazzo, D. Mengoni, M. Siciliano, D. Bazzacco, E. Teruya, M. Queiser, D. Schneiders, Andreas Görgen, A. Gottardo, Fernando Scarlassara, L. Lewandowski, C. Michelagnoli, J. F. Smith, G. Pollarolo, K. Hadynska-Klek, M. Seidlitz, Tea Mijatović, B. Siebeck, J. J. Valiente-Dobón, J. Eberth, C. Müller-Gatermann, E. Sahin, K. O. Zell, D. R. Napoli, K. Wolf, Alberto Pullia, A. M. Stefanini, R. Hetzenegger, P. A. Söderström, D. Rosiak, Nunzio Itaco, Herbert Hess, Zs. Podolyák, C. Fransen, L. Corradi, and L. Kaya

Subjects
Physics, Spectrometer, Isotope, Proton, 010308 nuclear & particles physics, Shell (structure), Nuclear structure, Spin structure, 01 natural sciences, Nuclear physics, 0103 physical sciences, Neutron, AGATA, 010306 general physics
Abstract

The transitional nucleus 131Xe is investigated after multinucleon transfer (MNT) in the 136Xe+208Pb and 136Xe+238U reactions employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy and as an elusive reaction product in the fusion-evaporation reaction 124Sn(11B,p3n) 131Xe employing the HORUS γ-ray array coupled to a double-sided silicon strip detector (DSSSD) at the University of Cologne, Germany. The level scheme of 131Xe is extended to 5 MeV. A pronounced backbending is observed at ~ω ≈ 0.4 MeV along the negative-parity one-quasiparticle νh11/2(α = −1/2) band. The results are compared to the high-spin systematics of the Z = 54 isotopes and the N = 77 isotones. Large-scale shell-model calculations (LSSM) employing the PQM130, SN100PN, GCN50:82, SN100-KTH and a realistic effective interaction reproduce the experimental findings and provide guidance to elucidate the structure of the high-spin states. Further calculations in 129−132Xe provide insight into the changing nuclear structure along the Xe chain towards the N = 82 shell closure. Proton occupancy in the π 0h11/2 orbital is found to be decisive for the description of the observed backbending phenomenon.

Published
2018
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20. Corrigendum to: 'Shape dynamics in neutron-rich Kr isotopes: Coulomb excitation of 92Kr, 94Kr and 96Kr' [Nucl. Phys. A 899 (2013) 1–28]

Author

K. Moschner, Herbert Hess, Kathrin Wimmer, M. Pfeiffer, D. Mücher, M. Cappellazzo, E. Fiori, M. Rudigier, C. Mihai, Marcus Scheck, D. Cline, A. Blazhev, J. M. Daugas, K. Nowak, S. Das Gupta, V. Bildstein, Roman Gernhäuser, M. Zielińska, Iain Darby, P. J. Napiorkowski, R. Krücken, Fredrik Wenander, Georgi P. Georgiev, B. Siebeck, M. Kowalczyk, K. Nomura, M. Hackstein, L. M. Robledo, Joonas Konki, D. M. Filipescu, M. Seidlitz, H. De Witte, D. Radeck, R. R. Rodríguez-Guzmán, N. Marginean, Janne Pakarinen, D. G. Jenkins, P. Reiter, G. S. Simpson, R. Lutter, L. Bettermann, B. Bastin, M. J. Vermeulen, Marc Huyse, J. Litzinger, J. Van de Walle, B. S. Nara Singh, T. Davinson, T. Kröll, C. Bernards, K. O. Zell, Jan Diriken, Stefan Heinze, T. Thomas, R. Wadsworth, M. Albers, J. Jolie, Joakim Cederkäll, Susan Rigby, P. Thöle, P. Van Duppen, D. Voulot, Liam Gaffney, Jonathan Butterworth, C. Fransen, C. Bauer, and N. Warr

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Isotope, 0103 physical sciences, Neutron, Coulomb excitation, 010306 general physics, Shape dynamics, 01 natural sciences
Published
2016
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21. Studies of fission fragment yields via high-resolution gamma-ray spectroscopy

Author

K. Hauschild, Stefano Panebianco, A. Gottardo, A. Porta, Gry Merete Tveten, P Amador-Celdran, B. Siebeck, R. Shearman, A. Goasduff, D. Verney, E. Sahin, P. H. Regan, D. T. Doherty, L. Mathieu, Hans-Jurgen E. Hess, A. Lopez-Martens, V. W. Ingeberg, I. Matea, Georgi Georgiev, P. Reiter, G. Lorusso, Olivier Serot, Paola Marini, R Eloirdi, N. Warr, T. Materna, Raymond J. Carroll, Sunniva Siem, Zs. Podolyák, Stephan Oberstedt, Fabio Zeiser, H. De Witte, S. J. Rose, L. Qi, J. N. Wilson, M. Lebois, R. Lutter, J. Ljungvall, K. Rezynkina, D. L. Bleuel, K. Hadynska-Klek, J.A. Briz, M. Zielińska, M. Seidlitz, W. N. Catford, T. Konstantinopoulos, R. Lozeva, A. G. Smith, Andreas Oberstedt, Hambsch, FJ, Carjan, N, Rusko, I, 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), Laboratoire de physique subatomique et des technologies associées (SUBATECH), Université de Nantes - Faculté des Sciences et des Techniques, 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 de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), CEA Cadarache, 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 Bretagne-Pays de la Loire (IMT Atlantique), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), 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 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 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)

Subjects
Physics, Fission products, Science & Technology, Isotopes of uranium, 010308 nuclear & particles physics, Fission, QC1-999, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Physics, Multidisciplinary, Fission product yield, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Neutron temperature, Nuclear physics, Uranium-238, 0103 physical sciences, Physical Sciences, Neutron source, Neutron, 010306 general physics, Nuclear Experiment
Abstract

© The Authors, published by EDP Sciences, 2018. Precise spectroscopic information on the fast neutron induced fission of the 238U(n,f) reaction was recently gained using a new technique which involved coupling of the Miniball high resolution y-ray spectrometer and the LICORNE directional neutron source. The experiment allowed measurement of the isotopic fission yields for around 40 even-even nuclei at an incident neutron energy of around 2 MeV where yield data are very sparse. In addition spectroscopic information on very neutron-rich fission products was obtained. Results were compared to models, both the JEFF-3.1.1 data base and the GEF code, and large discrepancies for the S1 fission mode in the Sn/Mo isotope pair were discovered. This suggests that current models are overestimating the role played by spherical shell effects in fast neutron induced fission. In late 2017 and 2018 the nu-ball hybrid spectrometer will be constructed at the IPN Orsay to perform further experimental investigations with directional neutrons coupled to a powerful hybrid Ge/LaBr3 detector array. This will open up new possibilities for measurements of fission yields for fast-neutron-induced fission using the spectroscopic technique and will be complimentary to other methods being developed. ispartof: SCIENTIFIC WORKSHOP ON NUCLEAR FISSION DYNAMICS AND THE EMISSION OF PROMPT NEUTRONS AND GAMMA RAYS (THEORY-4) vol:169 ispartof: 4th Scientific Workshop on Nuclear Fission Dynamics and the Emission of Prompt Neutrons and Gamma Rays (Theory) location:BULGARIA, Varna date:20 Jun - 22 Jun 2017 status: published

Published
2018
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22. Enhanced Quadrupole and Octupole Strength in Doubly Magic Sn 132

Author

D. Rosiak, M. Seidlitz, P. Reiter, H. Naïdja, Y. Tsunoda, T. Togashi, F. Nowacki, T. Otsuka, G. Colò, K. Arnswald, T. Berry, A. Blazhev, M. J. G. Borge, J. Cederkäll, D. M. Cox, H. De Witte, L. P. Gaffney, C. Henrich, R. Hirsch, M. Huyse, A. Illana, K. Johnston, L. Kaya, Th. Kröll, M. L. Lozano Benito, J. Ojala, J. Pakarinen, M. Queiser, G. Rainovski, J. A. Rodriguez, B. Siebeck, and E

Published
2018
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23. Coulomb Excitation of (142) Xe

Author

S. Ilieva, P. J. Napiorkowski, M. Thürauf, C. Berner, G. S. Simpson, G. Rainovski, Th. Kröll, Liam Gaffney, B. Siebeck, J. Cederkäll, M. Matejska-Minda, D. Rosiak, M. Ramdhane, R. Lozeva, L. Werner, P. Reiter, C. Berger, M. Zielinska, C. Henrich, V. Bildstein, M. Seidlitz, G. de Angelis, Daniel Cox, M. von Schmid, J. Ojala, Janne Pakarinen, G. Fernández Martínez, H. B. Rhee, J. Snäll, K. Arnswald, A. Illana Sisón, T. Berry, N. Warr, G. Georgiev, H. De Witte, V. Vaquero Soto, European Commission, Federal Ministry of Education and Research (Germany), SCOAP, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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 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 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), 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
Physics, Large Hadron Collider, Spectrometer, ta114, 010308 nuclear & particles physics, Detector, Nuclear Theory, General Physics and Astronomy, ksenon, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, xenon, Nuclear physics, nuclear physics, 0103 physical sciences, Quadrupole, Physics::Accelerator Physics, Nuclear Physics - Experiment, MAGIC (telescope), ydinfysiikka, Nuclear Experiment, Beam (structure)
Abstract

5 pags., 2 figs. -- Open Access funded by Creative Commons Atribution Licence 4.0. -- Presented at the XXXV Mazurian Lakes Conference on Physics, Piaski, Poland, September 3–9, 2017., The even–even nucleus 142Xe lies north-east of the doubly magic 132Sn on the neutron-rich side of the nuclear chart. In order to gain further information on the octupole collectivity and the evolution of quadrupole collectivity in this region, a “safe” Coulomb excitation experiment was carried out at the new HIE-ISOLDE facility (CERN) at the end of 2016. As the gamma-ray detector the Miniball spectrometer was used. Beam and target nuclei were detected using C-REX, i.e. an array of segmented Si detectors, covering forward as well as backward angles in the laboratory frame., This work is supported by the German Federal Ministry of Education and Research (BMBF) under contract 05P15RDCIA, by the EU under contract ENSAR 262010, by ISOLDE and the IS548-MINIBALL Collaboration.

Published
2018
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24. Cross-shell excitations from the fp shell: Lifetime measurements in Zn61

Author

Michio Honma, B. Siebeck, B. Fu, Hans-Jurgen E. Hess, A. Vogt, D. Rosiak, K. Wolf, R. Altenkirch, T. Steinbach, C. Müller-Gatermann, R. Hetzenegger, K. Arnswald, Yutaka Utsuno, B. Birkenbach, M. Queiser, Tomoaki Togashi, A. Dewald, A. Blazhev, M. Seidlitz, L. Lewandowski, C. Fransen, P. Reiter, K. O. Zell, Thomas Braunroth, J. Jolie, R. Hirsch, J.-M. Régis, Takaharu Otsuka, L. Kaya, P. Petkov, J. Eberth, Noritaka Shimizu, D. Schneiders, and V. Karayonchev

Subjects
Physics, 010308 nuclear & particles physics, Excited state, 0103 physical sciences, Shell (structure), Prolate spheroid, Atomic physics, 010306 general physics, 01 natural sciences, Excitation
Abstract

Lifetimes of excited states in the neutron-deficient nucleus $^{61}\mathrm{Zn}$ were measured employing the recoil-distance Doppler-shift (RDDS) and the electronic fast-timing methods at the University of Cologne. The nucleus of interest was populated as an evaporation residue in $^{40}\mathrm{Ca}(^{24}\mathrm{Mg},n2p)^{61}\mathrm{Zn}$ and $^{58}\mathrm{Ni}(\ensuremath{\alpha},n)^{61}\mathrm{Zn}$ reactions at 67 and 19 MeV, respectively. Five lifetimes were measured for the first time, including the lifetime of the $5/{2}_{1}^{\ensuremath{-}}$ isomer at 124 keV. Short lifetimes from the RDDS analysis are corrected for Doppler-shift attenuation (DSA) in the target and stopper foils. Ambiguous observations in previous measurements were resolved. The obtained lifetimes are compared to predictions from different sets of shell-model calculations in the $fp$, ${f}_{5/2}p{g}_{9/2}$, and multishell $fp\text{\ensuremath{-}}{g}_{9/2}{d}_{5/2}$ model spaces. The band built on the $9/{2}_{1}^{+}$ state exhibits a prolate deformation with $\ensuremath{\beta}\ensuremath{\approx}0.24$. Especially, the inclusion of cross-shell excitation into the $1{d}_{5/2}$ orbital is found to be decisive for the description of collectivity in the first excited positive-parity band.

Published
2017
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25. High-spin structures in Xe132 and Xe133 and evidence for isomers along the N=79 isotones

Author

V. Karayonchev, E. Teruya, S. Szilner, E. Fioretto, Ching-Yen Wu, T. Mijatović, M. Queiser, N. Saed-Samii, P. Reiter, J. Eberth, A. O. Macchiavelli, S. J. Freeman, W. Gelletly, D. Cline, A. Blazhev, R. Hirsch, R. Teng, Andreas Görgen, A. B. Hayes, J. J. Valiente-Dobón, B. Siebeck, C. J. Pearson, K. Wolf, A. Gadea, Alberto Pullia, B. Birkenbach, Naotaka Yoshinaga, R. S. Chakrawarthy, F. Scarlassara, Agnese Giaz, O. Stezowski, Roberto Menegazzo, J. Jolie, W. Korten, B. Bruyneel, P. A. Söderström, K. Hadynska-Klek, M. Seidlitz, D. Mengoni, A. Gottardo, D. R. Napoli, B. Fu, A. Jungclaus, H. Hua, Robert Chapman, A. M. Stefanini, R. Hetzenegger, S. Lunardi, D. Montanari, E. Farnea, A. Vogt, A. Bracco, C. Wheldon, D. Bazzacco, P. H. Regan, G. Pollarolo, L. Kaya, J.-M. Régis, I. Y. Lee, M. Cromaz, Herbert Hess, C. A. Ur, L. Corradi, C. Michelagnoli, G. de Angelis, K. O. Zell, P. R. John, M. Siciliano, S. Leoni, G. Sletten, F. Recchia, K. Arnswald, G. Montagnoli, Ch. Fransen, C. Müller-Gatermann, Zs. Podolyák, F. C. L. Crespi, D. D. Warner, B. Szpak, J. F. Smith, X. Liang, E. Sahin, and P. Fallon

Subjects
Physics, Crystallography, 010308 nuclear & particles physics, 0103 physical sciences, Gammasphere, AGATA, Atomic physics, 010306 general physics, Spin (physics), 01 natural sciences
Abstract

Author(s): Vogt, A; Siciliano, M; Birkenbach, B; Reiter, P; Hadynska-Klȩk, K; Wheldon, C; Valiente-Dobon, JJ; Teruya, E; Yoshinaga, N; Arnswald, K; Bazzacco, D; Blazhev, A; Bracco, A; Bruyneel, B; Chakrawarthy, RS; Chapman, R; Cline, D; Corradi, L; Crespi, FCL; Cromaz, M; De Angelis, G; Eberth, J; Fallon, P; Farnea, E; Fioretto, E; Fransen, C; Freeman, SJ; Fu, B; Gadea, A; Gelletly, W; Giaz, A; Gorgen, A; Gottardo, A; Hayes, AB; Hess, H; Hetzenegger, R; Hirsch, R; Hua, H; John, PR; Jolie, J; Jungclaus, A; Karayonchev, V; Kaya, L; Korten, W; Lee, IY; Leoni, S; Liang, X; Lunardi, S; MacChiavelli, AO; Menegazzo, R; Mengoni, D; Michelagnoli, C; Mijatovic, T; Montagnoli, G; Montanari, D; Muller-Gatermann, C; Napoli, D; Pearson, CJ; Podolyak, Z; Pollarolo, G; Pullia, A; Queiser, M; Recchia, F; Regan, PH; Regis, JM; Saed-Samii, N; Sahin, E; Scarlassara, F; Seidlitz, M; Siebeck, B; Sletten, G; Smith, JF; Soderstrom, PA; Stefanini, AM; Stezowski, O; Szilner, S; Szpak, B; Teng, R; Ur, C; Warner, DD; Wolf, K; Wu, CY; Zell, KO | Abstract: The transitional nuclei Xe132 and Xe133 are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Both nuclei are populated (i) in Xe136+Pb208 MNT reactions employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (ii) in the Xe136+Pt198 MNT reaction employing the GAMMASPHERE spectrometer in combination with the gas-detector array CHICO, and (iii) as an evaporation residue after a Te130(α,xn)Xe134-xn fusion-evaporation reaction employing the HORUS γ-ray array at the University of Cologne. The high-spin level schemes are considerably extended above the Jπ=(7-) and (10+) isomers in Xe132 and above the 11/2- isomer in Xe133. The results are compared to the high-spin systematics of the Z=54 as well as the N=78 and N=79 chains. Furthermore, evidence is found for a long-lived (T1/2â‰1μs) isomer in Xe133 which closes a gap along the N=79 isotones. Shell-model calculations employing the SN100PN and PQM130 effective interactions reproduce the experimental findings and provide guidance to the interpretation of the observed high-spin features.

Published
2017
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26. Anomalies in the Charge Yields of Fission Fragments from the U(n,f)238 Reaction

Author

M. Zielińska, Stefano Panebianco, H. De Witte, S. J. Rose, V. W. Ingeberg, P. Reiter, K. Hadynska-Klek, M. Seidlitz, K. Rezynkina, W. N. Catford, Andreas Oberstedt, N. Warr, Paola Marini, D. L. Bleuel, P. H. Regan, D. Verney, A. G. Smith, M. Lebois, Stephan Oberstedt, Olivier Serot, J. N. Wilson, T. Konstantinopoulos, Amanda Porta, Fabio Zeiser, R. Lozeva, R. Shearman, R. Lutter, B. Siebeck, A. Goasduff, G. Lorusso, Georgi Georgiev, J. Ljungvall, Sunniva Siem, L. Mathieu, E. Sahin, D. T. Doherty, L. Qi, Hans-Jurgen E. Hess, R Eloirdi, I. Matea, A. Lopez-Martens, T. Materna, K. Hauschild, José Antonio Briz, Gry Merete Tveten, P Amador-Celdran, A. Gottardo, Raymond J. Carroll, and Zs. Podolyák

Subjects
Physics, Cold fission, Cluster decay, 010308 nuclear & particles physics, Neutron emission, Fission, Xenon-135, Isotopes of samarium, Nuclear Theory, General Physics and Astronomy, Fission product yield, 01 natural sciences, 7. Clean energy, Nuclear physics, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Neutron, Nuclear Experiment, 010306 general physics
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
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27. Isomers and high-spin structures in the N=81 isotones Xe135 and Ba137

Author

L. Kaya, M. Siciliano, A. Gengelbach, B. Birkenbach, P. Fallon, Herbert Hess, Agnese Giaz, W. Korten, X. Liang, D. Bazzacco, A. Bracco, Luna Pellegri, V. Vandone, Roberto Menegazzo, S. Lunardi, N. Saed-Samii, B. Bruyneel, M. Bowry, D. Montanari, M. Cromaz, C. Y. Wu, A. Vogt, D. Cline, L. Corradi, P. H. Regan, P. Reiter, A. Blazhev, K. O. Zell, P. R. John, W. Gelletly, K. Arnswald, R. Hirsch, R. Teng, Alberto Pullia, G. Sletten, J. F. Smith, D. Schneiders, E. Sahin, A. Gadea, C. J. Pearson, K. Hadynska-Klek, Robert Chapman, G. Montagnoli, G. Pollarolo, F. Scarlassara, Naotaka Yoshinaga, C. Müller-Gatermann, O. Stezowski, M. Seidlitz, F. Radeck, E. Fioretto, S. Leoni, A. O. Macchiavelli, E. Teruya, T. Mijatović, M. Queiser, G. de Angelis, A. M. Stefanini, J. Eberth, L. Lewandowski, Zs. Podolyák, E. Farnea, A. Gottardo, R. S. Chakrawarthy, D. Rosiak, P. A. Söderström, Andreas Görgen, H. Hua, A. B. Hayes, J. J. Valiente-Dobón, C. Wheldon, D. R. Napoli, K. Geibel, D. Mengoni, B. Fu, J. Jolie, A. Jungclaus, S. Szilner, F. C. L. Crespi, D. D. Warner, S. J. Freeman, T. Steinbach, C. A. Ur, F. Recchia, B. Szpak, Andreas Wiens, I. Y. Lee, C. Michelagnoli, and B. Siebeck

Subjects
Physics, Spectrometer, 010308 nuclear & particles physics, 0103 physical sciences, Quadrupole, SHELL model, Gammasphere, AGATA, Atomic physics, 010306 general physics, Spin (physics), 01 natural sciences
Abstract

The high-spin structures of the N = 81 isotones 135Xe and 137Ba are investigated after multinucleontransfer (MNT) and fusion-evaporation reactions. Both nuclei are populated in (i) 136Xe+238U and (ii) 136Xe+208Pb MNT reactions employing the high-resolution Advanced Gamma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (iii), in the 136Xe+198Pt MNT reaction employing the -ray array GAMMASPHERE in combination with the gas detector array Chico, and (iv) via a 11B+130Te fusion-evaporation reaction. The high-spin level schemes of 135Xe and 137Ba are considerably extended to higher energies. The 2058-keV (19=2 ) state in 135Xe is identified as an isomer, completing the systematics for the N = 81 isotones. Its half-life is measured to be 8.6(10) ns, corresponding to a transition probability of B(E2; 19=2 ! 15=2 ) = 0:539(69) W.u. Latest shell model calculations considering 132Sn as a closed core reproduce the experimental findings and provide guidance to the interpretation of the new levels. The experimentally deduced reduced quadrupole transition probabilities of the isomeric states are compared to shell-model predictions.

Published
2017
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28. Lifetime measurements in Ru100

Author

A. Kusoglu, T. Arici, A. Goasduff, A. Gottardo, D. Bonatsos, H. De Witte, P. Reiter, T. J. Mertzimekis, I. Matea, B. Melon, A. Gargano, P. Detistov, R. Lutter, Sotirios Harissopulos, Michael J. Eller, M. Axiotis, C. M. Petrache, N. Warr, G. Provatas, A. Astier, T. Konstantinopoulos, V. Foteinou, P. Petkov, L. Atanasova, S. Kaim, J. Ljungvall, Georgi P. Georgiev, M. Rocchini, K. A. Gladnishki, S. Roccia, M. Seidlitz, A. Nannini, A. Lagoyannis, Hans-Jurgen E. Hess, Alfred Dewald, A. Petrovici, D. Kocheva, B. Siebeck, T. Zerrouki, and Daisuke Suzuki

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, 010308 nuclear & particles physics, Yrast, Attenuation, 01 natural sciences, 7. Clean energy, symbols.namesake, Recoil, Critical point (thermodynamics), Excited state, 0103 physical sciences, symbols, Atomic physics, 010306 general physics, Doppler effect
Abstract

The nucleus 100Ru appears to be a good candidate for the E(5) critical point symmetry which describes the U(5)-SO(6) shape phase transition. To investigate this point with respect to the electromagnetic transition strengths, lifetime measurements of its yrast states have been performed using the recoil distance Doppler shift technique as well as the Doppler shift attenuation method. As a result, the lifetimes of the yrast 2+, 4+, and 8+ states were determined. The deduced transition strengths are compared to the E(5) predictions as well as to the results of excited Vampir and shell-model calculations. ispartof: Physical Review C vol:95 issue:1 status: published

Published
2017
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29. Anomalies in the Charge Yields of Fission Fragments from the $^{238}$U(n,f) Reaction

Author

J N, Wilson, M, Lebois, L, Qi, P, Amador-Celdran, D, Bleuel, J A, Briz, R, Carroll, W, Catford, H, De Witte, D T, Doherty, R, Eloirdi, G, Georgiev, A, Gottardo, A, Goasduff, K, Hadyńska-Klęk, K, Hauschild, H, Hess, V, Ingeberg, T, Konstantinopoulos, J, Ljungvall, A, Lopez-Martens, G, Lorusso, R, Lozeva, R, Lutter, P, Marini, I, Matea, T, Materna, L, Mathieu, A, Oberstedt, S, Oberstedt, S, Panebianco, Zs, Podolyák, A, Porta, P H, Regan, P, Reiter, K, Rezynkina, S J, Rose, E, Sahin, M, Seidlitz, O, Serot, R, Shearman, B, Siebeck, S, Siem, A G, Smith, G M, Tveten, D, Verney, N, Warr, F, Zeiser, M, Zielinska, 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 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 de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), CEA Cadarache, Université de Nantes - Faculté des Sciences et des Techniques, 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 Bretagne-Pays de la Loire (IMT Atlantique), 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 ), Laboratoire de physique subatomique et des technologies associées ( SUBATECH ), IMT Atlantique Bretagne-Pays de la Loire ( IMT Atlantique ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Nantes ( UN ), 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 de Sciences Nucléaires et de Sciences de la Matière ( CSNSM ), Direction des Applications Militaires ( DAM ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), 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 ), 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), and 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)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Physics::Atomic and Molecular Clusters, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 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. ispartof: Physical Review Letters vol:118 issue:22 ispartof: location:United States status: published

Published
2017
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30. Enhanced collectivity along the NÂ =Â Z line: Lifetime measurements in44Ti,48Cr, and52Fe

Author

Herbert Hess, K. O. Zell, P. Reiter, A. Blazhev, B. Birkenbach, A. Vogt, D. Schneiders, L. Coraggio, T. Steinbach, L. Lewandowski, J. Litzinger, Thomas Braunroth, A. Gargano, B. Fu, S. M. Lenzi, Alfred Dewald, D. Rosiak, C. Müller-Gatermann, K. Wolf, M. Seidlitz, R. Hirsch, M. Queiser, B. Siebeck, K. Arnswald, Nunzio Itaco, C. Fransen, Arnswald, K., Braunroth, T., Seidlitz, M., Coraggio, L., Reiter, P., Birkenbach, B., Blazhev, A., Dewald, A., Fransen, C., Fu, B., Gargano, A., Hess, H., Hirsch, R., Itaco, N., Lenzi, S. M., Lewandowski, L., Litzinger, J., Mã¼ller-gatermann, C., Queiser, M., Rosiak, D., Schneiders, D., Siebeck, B., Steinbach, T., Vogt, A., Wolf, K., Zell, K. O., and Müller-Gatermann, C.

Subjects
History, Nuclear and High Energy Physics, Lifetime measurement, Lifetime measurements, Nuclear Theory, B(E2) value, B(E2) values, N=Z nuclei, RDDS, 01 natural sciences, Education, Physics and Astronomy (all), symbols.namesake, Recoil, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Physics, Isotope, 010308 nuclear & particles physics, Isotone, lcsh:QC1-999, Computer Science Applications, symbols, Atomic physics, Hamiltonian (quantum mechanics), lcsh:Physics
Abstract

Lifetimes of the 2 1 + states in 44Ti, 48,50Cr, and 52Fe were determined with high accuracy exploiting the recoil distance Doppler-shift method. The reduced E2 transition strengths of 44Ti and 52Fe differ considerably from previously known values. A systematic increase in collectivity is found for the N = Z nuclei compared to neighboring isotopes. The B ( E2 ) values along the Ti, Cr, and Fe isotopic chains are compared to shell-model calculations employing established interactions for the 0 f 1 p shell, as well as a novel effective shell-model Hamiltonian starting from a realistic nucleon–nucleon potential. The theoretical approaches underestimate the B ( E2 ) values for the lower-mass Ti isotopes. Strong indication is found for particle-hole cross-shell configurations, recently corroborated by similar results for the neighboring isotone 42Ca.

Published
2017

31. Low-energy Coulomb excitation of Sr96,98 beams

Author

Sunniva Siem, K. Moschner, D. T. Doherty, P. Marley, H. Goutte, S. Péru, P. Reiter, P. A. Butler, Gry Merete Tveten, H. Hess, M. J. Vermeulen, P. J. Napiorkowski, P. Delahaye, J. Iwanicki, W. Korten, B. Bruyneel, Therese Renstrøm, R. Gernhäuser, J. Srebrny, Andreas Görgen, A. C. Larsen, J. Van de Walle, K. Wrzosek-Lipska, Georgi P. Georgiev, B. Siebeck, M. Zielinska, A. Blazhev, H. De Witte, C. Bauer, D. G. Jenkins, N. Warr, M. Seidlitz, C. Sotty, Fredrik Wenander, B. Bastin, Stéphane Hilaire, Janne Pakarinen, Conor Fitzpatrick, Andreas Wiens, D. Voulot, Andreas Ekström, I. Stefanescu, R. Lutter, A. Dijon, A. Petts, Joakim Cederkäll, J. Ljungvall, N. Bree, Jonathan Butterworth, C. Fransen, and E. Clément

Subjects
Physics, Large Hadron Collider, Spectrometer, Isotope, 010308 nuclear & particles physics, Diagonal, Coulomb excitation, 01 natural sciences, Matrix (mathematics), Low energy, 0103 physical sciences, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, 010306 general physics, Ground state
Abstract

The structure of neutron-rich 96,98Sr nuclei was investigated by low-energy safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN, with the MINIBALL spectrometer. A rich set of transitional and diagonal E2 matrix elements, including those for non-yrast structures, has been extracted from the differential Coulomb-excitation cross sections. The results support the scenario of a shape transition at N = 60, giving rise to the coexistence of a highly deformed prolate and a spherical configuration in 98Sr, and are compared to predictions from several theoretical calculations. The experimental data suggest a significant contribution of the triaxal degree of freedom in the ground state of both isotopes. In addition, experimental information on low-lying states in 98Rb has been obtained.

Published
2016
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32. γ-ray spectroscopy ofP33andS33after fusion-evaporation reactions

Author

K. Arnswald, F. Haas, Herbert Hess, T. Steinbach, A. Vogt, B. Fu, C. Fransen, T. Thomas, R. Hirsch, K. O. Zell, G. Friessner, D. Schneiders, B. Siebeck, K. Wolf, B. Birkenbach, A. Blazhev, A. Hennig, P. Reiter, L. Lewandowski, M. Bouhelal, M. Seidlitz, and Anna Wendt

Subjects
Physics, Fusion, Spins, 010308 nuclear & particles physics, Excited state, 0103 physical sciences, Evaporation, Atomic physics, 010306 general physics, Spectroscopy, 01 natural sciences, Omega
Abstract

Excited states with intermediate and high spins in $^{33}\mathrm{P}$ and $^{33}\mathrm{S}$ have been populated using the $^{26}\mathrm{Mg}(^{13}\mathrm{C},np\ensuremath{\alpha})$ and $^{26}\mathrm{Mg}(^{13}\mathrm{C},2n\ensuremath{\alpha})$ fusion-evaporation reactions. The level schemes of both nuclei have been considerably extended. Utilizing $\ensuremath{\gamma}\ensuremath{\gamma}$ angular correlations the spin-parity assignment of the new excited states in $^{33}\mathrm{P}$ has been investigated. The experimentally determined results from both nuclei were compared to $0\ensuremath{\hbar}\ensuremath{\omega}$ and $1\ensuremath{\hbar}\ensuremath{\omega}$ truncated p-sd-pf shell-model calculations utilizing the PSDPF interaction, showing a very good agreement between experiment and theory.

Published
2016
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33. Production and Study of Neutron-rich Nuclei Using the LICORNE Directional Neutron Source

Author

R. Shearman, R. Lutter, Sunniva Siem, A. Gottardo, V. W. Ingeberg, D. Verney, D. L. Bleuel, P. Reiter, L. Qi, W. N. Catford, Andreas Oberstedt, José Antonio Briz, M. Lebois, A. G. Smith, Paola Marini, M. Zielinska, Giuseppe Lorusso, T. Konstantinopoulos, Georgi P. Georgiev, Gry Merete Tveten, A. Lopez-Martens, J. N. Wilson, P Amador-Celdran, Stephan Oberstedt, K. Hadynska-Klek, K. Hauschild, M. Seidlitz, L. Mathieu, R. Lozeva, N. Warr, K. Rezynkina, S. Panebianco, Amanda Porta, Raymond J. Carroll, Zs. Podolyák, H. De Witte, S. J. Rose, M Hess, P. H. Regan, T. Materna, J. Ljungvall, A. Goasduff, Fabio Zeiser, E. Sahin, D. T. Doherty, R Eloirdi, B. Siebeck, I. Matea, 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), 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)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), 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 de Sciences Nucléaires et de Sciences de la Matière (CSNSM), 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), 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), 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), 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 National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), 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), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes - Faculté des Sciences et des Techniques, Université de Strasbourg (UNISTRA)-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 Bretagne-Pays de la Loire (IMT Atlantique), and Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)

Subjects
Physics, education.field_of_study, Spins, Spectrometer, 010308 nuclear & particles physics, Fission, [PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph], Population, Nuclear Theory, General Physics and Astronomy, Neutron radiation, 01 natural sciences, Nuclear physics, 0103 physical sciences, Neutron source, Neutron, Atomic physics, 010306 general physics, Spectroscopy, education, Nuclear Experiment
Abstract

We have recently successfully demonstrated a new technique for production and study of many of the most exotic neutron-rich nuclei at moderate spins. LICORNE, a newly developed directional inverse-kinematic fast neutron source at the IPN Orsay, was coupled to the MINIBALL high resolution γ-ray spectrometer to study nuclei the furthest from stability using the 238U(n,f) reaction. This reaction and 232Th(n,f) are the most neutron-rich fission production mechanisms achievable and can be used to simultaneously populate hundreds of neutron-rich nuclei up to spins of ≈ 16ℏ. High selectivity in the experiment was achieved via triple γ-ray coincidences and the use of a 400 ns period pulsed neutron beam, a technique which is unavailable to other population mechanisms such as 235U(nth,f) and 252Cf(SF). The pulsing allows time correlations to be exploited to separate delayed γ rays from isomeric states in the hundreds of nuclei produced, which are then used to cleanly select a particular nucleus and its exotic binary partners. In the recent experiment, several physics cases are simultaneously addressed such as shape coexistence, the evolution of shell closures far from stability, and the spectroscopy of nuclei in the r-process path near N = 82. Preliminary physics results on anomalies in the 238U(n,f) fission yields and the structure of the 138Te and 100Sr nuclei will soon be published. A future project, ν-ball, to couple LICORNE with a hybrid escape-suppressed spectrometer to refine further the technique and achieve a large increase in the observational limit is discussed. ispartof: pages:395-401 ispartof: Acta Physica Polonica B vol:48 issue:3 pages:395-401 ispartof: location:Zakopane: POLAND status: published

Published
2016
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34. Erratum: Spectroscopic Quadrupole Moments inSr96,98: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes atN=60[Phys. Rev. Lett.116, 022701 (2016)]

Author

Georgi P. Georgiev, N. Bree, Gry Merete Tveten, W. Korten, D. G. Jenkins, R. Lutter, A. C. Larsen, A. Blazhev, Therese Renstrøm, P. J. Napiorkowski, P. Delahaye, P. Marley, B. Bruyneel, J. Van de Walle, J. Ljungvall, Roman Gernhäuser, K. Wrzosek-Lipska, P. A. Butler, K. Moschner, P. Reiter, Sunniva Siem, B. Siebeck, Herbert Hess, Emyr Clement, J. Iwanicki, M. J. Vermeulen, S. Péru, A. Petts, Conor Fitzpatrick, D. T. Doherty, D. Voulot, F. Wenander, M. Zielińska, Andreas Wiens, M. Seidlitz, C. Fransen, J. Libert, Andreas Görgen, C Sotty, Stéphane Hilaire, Janne Pakarinen, C. Bauer, Andreas Ekström, I. Stefanescu, A. Dijon, Jonathan Butterworth, J. Srebrny, H. Goutte, B. Bastin, N. Warr, and H. De Witte

Subjects
Physics, Nuclear magnetic resonance, 010308 nuclear & particles physics, 0103 physical sciences, Quadrupole, General Physics and Astronomy, Neutron, Atomic physics, 010306 general physics, 01 natural sciences, Isotopes of strontium
Published
2016
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35. Structure of low-lying states inSm140studied by Coulomb excitation

Author

Thierry Stora, F. Giacoppo, Therese Renstrøm, F. Nowacki, D. A. Fink, V. N. Fedosseev, R. Lutter, C. Bauer, M. Zielinska, M. D. Seliverstov, P. Hoff, F. L. Bello Garrote, W. Korten, P. Reiter, P. J. Napiorkowski, J. Libert, J. P. Delaroche, Michel Girod, H. De Witte, B. Siebeck, Sebastian Rothe, S. Bönig, Sunniva Siem, H. Naïdja, Andreas Görgen, J. Srebrny, Gry Merete Tveten, P. Thöle, A. Damyanova, B. Bounthong, P. L. Molkanov, E. Rapisarda, Janne Pakarinen, Tamas Gabor Tornyi, Nobuaki Imai, N. Warr, K. Hadynska-Klek, P. Van Duppen, M. J. Vermeulen, D. Voulot, F. Wenander, A. C. Larsen, B. A. Marsh, M. Klintefjord, Institut de pharmacologie moléculaire et cellulaire (IPMC), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), 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), 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), Département de Physique Nucléaire (ex SPhN) (DPHN), 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)-Université Paris-Saclay, Centre de Recherche Saint-Antoine (UMRS893), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM), Heavy Ion Laboratory, University of Warsaw (UW), Department of Physics [Jyväskylä Univ] (JYU), University of Jyväskylä (JYU), European Organization for Nuclear Research (CERN), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), École des Mines de Douai (Mines Douai EMD), Institut Mines-Télécom [Paris] (IMT), Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Work (thermodynamics), Large Hadron Collider, ta114, Ion beam, 010308 nuclear & particles physics, Coulomb excitation, deformed nuclei, State (functional analysis), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 0103 physical sciences, Quadrupole, samarium, Atomic physics, Deformation (engineering), 010306 general physics, Excitation
Abstract

The electromagnetic structure of 140Sm was studied in a low-energy Coulomb excitation experiment with a radioactive ion beam from the REX-ISOLDE facility at CERN. The 2+ and 4+ states of the ground-state band and a second 2+ state were populated by multistep excitation. The analysis of the differential Coulomb excitation cross sections yielded reduced transition probabilities between all observed states and the spectroscopic quadrupole moment for the 2+ 1 state. The experimental results are compared to large-scale shell model calculations and beyond-mean-field calculations based on the Gogny D1S interaction with a five-dimensional collective Hamiltonian formalism. Simpler geometric and algebraic models are also employed to interpret the experimental data. The results indicate that 140Sm shows considerable γ softness, but in contrast to earlier speculation no signs of shape coexistence at low excitation energy. This work sheds more light on the onset of deformation and collectivity in this mass region. 15 pages, 12 figures ispartof: Physical Review C vol:93 issue:5 status: published

Published
2016
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36. Pygmy dipole resonance inCe140via inelastic scattering ofO17

Author

Alberto Pullia, S. Bottoni, A. Jungclaus, D. Bazzacco, C. A. Ur, J. Eberth, J. Ljungvall, N. Blasi, P. Reiter, M. Kmiecik, F. Recchia, A. Giaz, Herbert Hess, S. Lunardi, A. Maj, R. Menegazzo, A. Gottardo, B. Siebeck, Elena Litvinova, Oliver Wieland, E. G. Lanza, G. de Angelis, A. Bracco, Nils Paar, R. Avigo, M. Krzysiek, M. Ciemala, K. Mazurek, E. Farnea, P. Bednarczyk, S. Leoni, G. Benzoni, R Isocarte, A. I. Morales, Begoña Quintana, F. C. L. Crespi, B. Birkenbach, C. Michelagnoli, D. Rosso, R. Nicolini, M. D. Salsac, P. Désesquelles, A. Gadea, D. Mengoni, B Milion, S. Ceruti, S. Brambilla, P. A. Söderström, D. R. Napoli, F. Camera, M. Zieblinski, J. Grebosz, Andreas Görgen, J. J. Valiente-Dobón, Luna Pellegri, and Sunniva Siem

Subjects
Physics, 010308 nuclear & particles physics, Isoscalar, Form factor (quantum field theory), Inelastic scattering, 01 natural sciences, 7. Clean energy, Resonance (particle physics), Dipole, Excited state, 0103 physical sciences, Neutron, Atomic physics, Born approximation, 010306 general physics
Abstract

The γ decay from the high-lying states of ^140Ce excited via inelastic scattering of ^17O at a bombarding energy of 340 MeV was measured using the high-resolution AGATA-demonstrator array in coincidence with scattered ions detected in two segmented Δ E-E silicon detectors. Angular distributions of scattered ions and emitted γ rays were measured, as well as their differential cross sections. The excitation of 1^− states below the neutron separation energy is similar to the one obtained in reactions with the α isoscalar probe. The comparison between the experimental differential cross sections and the corresponding predictions using the distorted-wave Born approximation allowed us to extract the isoscalar component of identified 1^− pygmy states. For this analysis the form factor obtained by folding microscopically calculated transition densities and optical potentials was used.

Published
2016
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37. Spectroscopic Quadrupole Moments inSr96,98: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes atN=60

Author

B. Bastin, C. Fransen, P. Marley, Sunniva Siem, W. Korten, P. J. Napiorkowski, P. Reiter, Conor Fitzpatrick, P. Delahaye, J. Iwanicki, R. Gernhäuser, C Sotty, K. Moschner, D. T. Doherty, N. Bree, B. Bruyneel, D. Voulot, Herbert Hess, C. Bauer, M. Vermeulen, Emyr Clement, N. Warr, Jonathan Butterworth, R. Lutter, D. G. Jenkins, J. Srebrny, M. Seidlitz, J. Libert, A Dijon, A. Blazhev, A. C. Larsen, Georgi Georgiev, P. A. Butler, Andreas Görgen, Gry Merete Tveten, H. Goutte, H. De Witte, S. Péru, Fredrik Wenander, A. Petts, Andreas Ekström, I. Stefanescu, Therese Renstrøm, M. Zielinska, J. Van de Walle, Stéphane Hilaire, Janne Pakarinen, J. Ljungvall, Andreas Wiens, B. Siebeck, and K. Wrzosek-Lipska

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Nuclear Theory, General Physics and Astronomy, Coulomb excitation, Prolate spheroid, 01 natural sciences, Isotopes of strontium, Nuclear magnetic resonance, Hamiltonian formalism, 0103 physical sciences, Quadrupole, Physics::Accelerator Physics, Neutron, Atomic physics, 010306 general physics, Mixing (physics)
Abstract

Neutron-rich {96,98}Sr isotopes have been investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross sections. These results allow, for the first time, the drawing of definite conclusions about the shape coexistence of highly deformed prolate and spherical configurations. In particular, a very small mixing between the coexisting states is observed, contrary to other mass regions where strong mixing is present. Experimental results have been compared to beyond-mean-field calculations using the Gogny D1S interaction in a five-dimensional collective Hamiltonian formalism, which reproduce the shape change at N=60.

Published
2016
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38. Gamma decay of the possible 1- two-phonon state in 140Ce excited via inelastic scattering of 17O

Author

B. Siebeck, S. Bottoni, A. Gadea, E. Farnea, N. Blasi, S. Ceruti, F. Camera, A. Bracco, K. Mazurek, Andreas Görgen, B. Birkenbach, F. Recchia, G. Benzoni, J. J. Valiente-Dobón, S. Leoni, E. G. Lanza, R. Avigo, Luna Pellegri, A. Maj, S. Lunardi, C. A. Ur, A. Giaz, A. Gottardo, A. I. Morales, B. Million, R. Nicolini, Sunniva Siem, Roberto Isocrate, F. C. L. Crespi, P. Bednarczyk, D. R. Napoli, D. Bazzacco, G. de Angelis, M. Krzysiek, M. Ciemala, M. Kmiecik, O. Wieland, D. Mengoni, C. Michelagnoli, M. Zieblinski, and J. Grebosz

Subjects
Physics, Physics and Astronomy (all), Phonon, Excited state, Gamma ray, General Physics and Astronomy, State (functional analysis), Inelastic scattering, Atomic physics
Published
2016

39. Collective 2$^{+1}$ excitations in$^{206}$Po and$^{208,210}$Rn

Author

C. Bernards, P. Reiter, Jouni Suhonen, E. Rapisarda, H. De Witte, Marcus Scheck, V. Werner, Joonas Konki, A. Vogt, Rauno Julin, M. Thürauf, K. Reynders, J. Elseviers, A. Damyanova, S. Sambi, T. Grahn, T. Steinbach, K. Wrzosek-Lipska, M. Rudiger, C. Bauer, T. De Coster, M. J. Vermeulen, M. Venhart, Liam Gaffney, M. Zielińska, M. Pfeiffer, Martin Veselsky, D. Radeck, P. Peura, N. Kesteloot, Th. Kröll, S. Bönig, Marc Huyse, S. Stolze, L. Lewandowski, B. Siebeck, U. Jakobsson, K. Auranen, M. Seidlitz, Panu Rahkila, A. Herzáň, A. Blazhev, P. Thoele, Janne Pakarinen, M. D. Salsac, Lotta Jokiniemi, M. Albers, P. A. Butler, K. Moschner, P. Van Duppen, N. Warr, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Hadron, Nuclear Theory, radon, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Isotopes of palladium, collective excitation, Excited state, 0103 physical sciences, Quasiparticle, Physics::Accelerator Physics, Atomic physics, 010306 general physics, Nuclear Experiment, Open shell, polonium, Excitation, excited states
Abstract

In the present study, $B(E2; 2^{+}_{1}\rightarrow 0^{+}_{1})$ values have been measured in the 208,210Rn and 206Po nuclei through Coulomb excitation of re-accelerated radioactive beams in inverse kinematics at CERN-ISOLDE. These nuclei have been proposed to lie in, or at the boundary of the region where the seniority scheme should persist. However, contributions from collective excitations are likely to be present when moving away from the N=126 closed shell. Such an effect is confirmed by the observed increased collectivity of the $2^{+}_{1}\rightarrow 0^{+}_{1}$ transitions. Experimental results have been interpreted with the aid of theoretical studies carried out within the BCS-based QRPA framework.

Published
2016
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40. Publisher’s Note:Rb379760: The Cornerstone of the Region of Deformation aroundA∼100[Phys. Rev. Lett.115, 172501 (2015)]

Author

Ph Morel, R. Chevrier, Marcus Scheck, P. Reiter, J. M. Daugas, N. Bree, C. Sotty, Georgi P. Georgiev, P. J. Napiorkowski, F. Wenander, A. Blazhev, H. De Witte, T. Kröll, Liam Gaffney, G. S. Simpson, F. G. Kondev, T. Davinson, M. Zielińska, J. Konki, J. Pakarinen, M. Seidlitz, K. Geibel, Jan Diriken, B. Siebeck, K. Hadynska-Klek, D. L. Balabanski, S. Das Gupta, Andrew Stuchbery, N. Warr, and H. Törnqvist

Subjects
Physics, Classical mechanics, General Physics and Astronomy, Coulomb excitation, Deformation (meteorology)
Published
2015
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41. Rb973760: The Cornerstone of the Region of Deformation aroundA∼100

Author

G. S. Simpson, T. Kröll, A. Blazhev, J. Konki, D. L. Balabanski, R. Chevrier, Andrew Stuchbery, Jan Diriken, J. M. Daugas, F. G. Kondev, Janne Pakarinen, C. Sotty, B. Siebeck, Philippe Morel, M. Zielińska, Georgi P. Georgiev, P. Reiter, S. Das Gupta, K. Hadynska-Klek, F. Wenander, M. Seidlitz, Liam Gaffney, Marcus Scheck, K. Geibel, H. Törnqvist, H. De Witte, P. J. Napiorkowski, N. Warr, N. Bree, and Thomas Davinson

Subjects
General Physics and Astronomy
Published
2015
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42. Study of Octupole Collectivity in 146Nd and 148Sm Using the New Coulomb Excitation Set-up at ALTO

Author

P. Matuszczak, Liam Gaffney, P. Reiter, L. Próchniak, H. De Witte, T. Konstantinopoulos, W. Korten, Alain Goasduff, K. Wrzosek-Lipska, D. Rosiak, M. Komorowska, R. Lutter, B. Siebeck, M. Thürauf, D. T. Doherty, M. Zielińska, Marcus Scheck, Herbert Hess, K. Hadynska-Klek, E. T. Gregor, M. Seidlitz, I. Matea, J. Ljungvall, Georgi P. Georgiev, W. Piątek, M. Klintefjord, Andreas Görgen, N. Warr, A. Gottardo, P. A. Butler, P. J. Napiorkowski, G. G. O'Neill, R. Briselet, 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 de Sciences Nucléaires et de Sciences de la Matière (CSNSM SNO), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Univ. Paris-Sud, 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), and 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)

Subjects
Physics, [PHYS]Physics [physics], NUCLEI, 010308 nuclear & particles physics, media_common.quotation_subject, Nuclear Theory, General Physics and Astronomy, Charge density, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Asymmetry, Nuclear physics, Reflection (mathematics), Excited state, Neutron number, 0103 physical sciences, Atomic nucleus, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, media_common
Abstract

International audience; 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 approximate to 8 8 and N approximate to 1 3 4, 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 Nd-146 and Sm-148. In particular, the strengths of the < 3(-)parallel to E3 parallel to 0(+)> and < 1(-)parallel to E3 parallel to 4(+)> matrix elements will provide a clear distinction between octupole vibration and rigid deformation.

Published
2015
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43. (97)(37)Rb(60): The Cornerstone of the Region of Deformation around A ∼ 100 [corrected]

Author

C, Sotty, M, Zielińska, G, Georgiev, D L, Balabanski, A E, Stuchbery, A, Blazhev, N, Bree, R, Chevrier, S, Das Gupta, J M, Daugas, T, Davinson, H, De Witte, J, Diriken, L P, Gaffney, K, Geibel, K, Hadyńska-Klȩk, F G, Kondev, J, Konki, T, Kröll, P, Morel, P, Napiorkowski, J, Pakarinen, P, Reiter, M, Scheck, M, Seidlitz, B, Siebeck, G, Simpson, H, Törnqvist, N, Warr, and F, Wenander

Abstract

Excited states of the neutron-rich nuclei (97,99)Rb were populated for the first time using the multistep Coulomb excitation of radioactive beams. Comparisons of the results with particle-rotor model calculations provide clear identification for the ground-state rotational band of (97)Rb as being built on the πg(9/2) [431] 3/2(+) Nilsson-model configuration. The ground-state excitation spectra of the Rb isotopes show a marked distinction between single-particle-like structures below N=60 and rotational bands above. The present study defines the limits of the deformed region around A∼100 and indicates that the deformation of (97)Rb is essentially the same as that observed well inside the deformed region. It further highlights the power of the Coulomb-excitation technique for obtaining spectroscopic information far from stability. The (99)Rb case demonstrates the challenges of studies with very short-lived postaccelerated radioactive beams.

Published
2015

44. Multitude of2+discrete states inSn124observed via the(O17,O′17γ)reaction: Evidence for pygmy quadrupole states

Author

N. Tsoneva, D. Mengoni, S. Ceruti, R. Avigo, J. Grebosz, D. Bazzacco, B. Birkenbach, A. Giaz, M. Kmiecik, A. Gottardo, O. Wieland, S. Bottoni, K. Mazurek, B. Siebeck, Horst Lenske, Roberto Isocrate, Luna Pellegri, N. Blasi, D. R. Napoli, A. Bracco, A. Maj, C. A. Ur, G. Benzoni, P. Bednarczyk, S. Leoni, J. J. Valiente-Dobón, Sunniva Siem, R. Nicolini, F. C. L. Crespi, A. Gadea, F. Camera, Andreas Görgen, E. Farnea, B. Million, S. Lunardi, F. Recchia, A. I. Morales, G. de Angelis, M. Krzysiek, M. Ciemala, and C. Michelagnoli

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, Quadrupole, Degrees of freedom (physics and chemistry), Density functional theory, Born approximation, Atomic physics, Nuclear Experiment, Resonance (particle physics), Intensity (heat transfer), Excitation, Energy (signal processing)
Abstract

A multitude of discrete ${2}^{+}$ states in $^{124}\text{Sn}$ with energy up to 5 MeV were populated and identified with the $(^{17}\text{O}$, $^{17}\mathrm{O}^{\ensuremath{'}}\ensuremath{\gamma})$ reaction at 340 MeV. Cross sections were compared with distorted wave Born approximation predictions and in general a good agreement was found. The measured energy and intensity distributions of the ${2}^{+}$ states are very similar to the predictions based on self-consistent density functional theory and extended QRPA approach accounting for multiphonon degrees of freedom. This provides evidence of the excitation of the pygmy quadrupole resonance in skin nuclei.

Published
2015
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45. Evolution of quadrupole collectivity inN=80isotones toward theZ=64subshell gap: TheB(E2;21+→01+)value ofSm142

Author

S. Ilieva, S. Bönig, C. Stahl, E. Rapisarda, H. De Witte, N. Warr, A. Blazhev, B. Siebeck, Thierry Stora, R. Lutter, K. A. Gladnishki, D. Radeck, J. Jolie, V. Werner, Fredrik Wenander, A Damyanova, G. Rainovski, Marcus Scheck, Janne Pakarinen, Norbert Pietralla, M. Thürauf, C. Bauer, R. Stegmann, D. Voulot, T. Thomas, M. Vermeulen, P. Reiter, M. Danchev, and P. Thöle

Subjects
Physics, Nuclear and High Energy Physics, Valence (chemistry), Quadrupole, Atomic number, Coulomb excitation, Sensitivity (control systems), Atomic physics
Abstract

It was shown that the evolution of the $B(E2;{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})$ values in $N$ = 80 isotones from Te to Nd is affected by the underlying subshell structure. This manifests itself in the observation of the local suppression of the $B(E2)$ value at $Z=58$ with respect to the neighboring nuclei $^{136}\mathrm{Ba}$ and $^{140}\mathrm{Nd}$. To investigate this shell sensitivity toward the $Z=64$ subshell gap, the $B(E2;{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})$ value of the unstable nucleus $^{142}\mathrm{Sm}$ was measured utilizing the projectile Coulomb excitation technique. The radioactive ion beam (RIB) experiment was performed at the REX-ISOLDE facility at CERN. The $B(E2)$ value of $32\phantom{\rule{0.16em}{0ex}}(4)\phantom{\rule{0.16em}{0ex}}\mathrm{W}.\mathrm{u}.$ reflects the impact of the $\ensuremath{\pi}(1{g}_{7/2}\phantom{\rule{0.16em}{0ex}}2{d}_{5/2})$ subshell closure at $Z=64$ with respect to a linear scaling of collectivity with valence proton number.

Published
2015
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46. Erratum: Evidence for a Smooth Onset of Deformation in the Neutron-Rich Kr Isotopes [Phys. Rev. Lett.108, 062701 (2012)]

Author

C. Fransen, Takaharu Otsuka, C. Bauer, M. Kowalczyk, P. Reiter, N. Warr, G. S. Simpson, R. Krücken, S. Das Gupta, M. Rudigier, Jonathan Butterworth, P. Van Duppen, C. Bernards, H. De Witte, T. Davinson, T. Thomas, Iain Darby, Kentaro Nomura, B. Bastin, T. Kröll, D. G. Jenkins, D. Voulot, F. Wenander, E. Fiori, Marc Huyse, P. Thöle, Liam Gaffney, Georgi P. Georgiev, P. J. Napiorkowski, M. Hackstein, Stefan Heinze, R. Lutter, R. Wadsworth, J. Konki, Joakim Cederkäll, K. O. Zell, N. Marginean, Janne Pakarinen, D. Mücher, Marcus Scheck, J. M. Daugas, J. Litzinger, Roman Gernhäuser, M. Albers, J. Jolie, M. Zielińska, Susan Rigby, L. M. Robledo, D. Cline, A. Blazhev, M. Seidlitz, M. J. Vermeulen, V. Bildstein, B. S. Nara Singh, M. Pfeiffer, Pedro Sarriguren, B. Siebeck, D. M. Filipescu, Jan Diriken, C. Mihai, D. Radeck, L. Bettermann, K. Moschner, Herbert Hess, Kathrin Wimmer, M. Cappellazzo, R. R. Rodríguez-Guzmán, K. Nowak, and J. Van de Walle

Subjects
Physics, Nuclear physics, Isotope, General Physics and Astronomy, Neutron, Deformation (meteorology)
Published
2015
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47. Publisher's Note: Isospin symmetry in thesdshell: Transition strengths in the neutron-deficientsdshell nucleusAr33[Phys. Rev. C90, 054301 (2014)]

Author

A. Jungclaus, Benedicte Million, J. Gerl, A. Blazhev, A. Bracco, P. Doornenbal, P. Reiter, F. Ameil, H. J. Wollersheim, Jnaneswari Gellanki, Dirk Rudolph, A. I. Morales, M. Hackstein, K. Geibel, Douglas D. DiJulio, H. Grawe, N. Braun, S. Pietri, E. Merchan, B. Siebeck, Zs. Podolyák, F. Camera, L. Scruton, K. Moschner, M. Reese, D. Ralet, Joakim Cederkäll, T. Habermann, O. Wieland, N. Warr, Robert Hoischen, Anna Wendt, Jan Taprogge, J. Grbosz, Pavel Golubev, B. S. Nara Singh, G. Guastalla, D. Bloor, Norbert Pietralla, M. A. Bentley, P. Boutachkov, Alejandro Algora, M. Bowry, and F. C. L. Crespi

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, medicine.anatomical_structure, Isospin, Shell (structure), medicine, Neutron, Coulomb excitation, Atomic physics, Nucleus, Symmetry (physics)
Abstract

A. Wendt et al. ; 1 pag. ; PACS number(s): 21.10.Hw, 23.20.Js, 25.70.De, 27.30.+t, 99.10.Fg

Published
2015
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48. Testing refined shell-model interactions in thesdshell: Coulomb excitation ofNa26

Author

P. Reiter, Fredrik Wenander, M. J. Vermeulen, Marcus Scheck, N. Warr, T. Kröll, B. Siebeck, Janne Pakarinen, Marc Huyse, H. De Witte, A. Blazhev, R. Altenkirch, J. Elseviers, D. Schneiders, R. Lutter, F. Radeck, M. Seidlitz, C. Sotty, D. Voulot, Liam Gaffney, P. Van Duppen, P. A. Butler, Herbert Hess, C. Bauer, and Norbert Pietralla

Subjects
Physics, Nuclear and High Energy Physics, Matrix (mathematics), Valence (chemistry), Excited state, Shell (structure), Coulomb barrier, Neutron, Observable, Coulomb excitation, Atomic physics
Abstract

Background: Shell-model calculations crucially depend on the residual interaction used to approximate the nucleon-nucleon interaction. Recent improvements to the empirical universal $sd$ interaction (USD) describing nuclei within the $sd$ shell yielded two new interactions---USDA and USDB---causing changes in the theoretical description of these nuclei.Purpose: Transition matrix elements between excited states provide an excellent probe to examine the underlying shell structure. These observables provide a stringent test for the newly derived interactions. The nucleus $^{26}\mathrm{Na}$ with 7 valence neutrons and 3 valence protons outside the doubly-magic ${}^{16}\mathrm{O}$ core is used as a test case.Method: A radioactive beam experiment with $^{26}\mathrm{Na}$ (${T}_{1/2}=1,07s$) was performed at the REX-ISOLDE facility (CERN) using Coulomb excitation at safe energies below the Coulomb barrier. Scattered particles were detected with an annular Si detector in coincidence with $\ensuremath{\gamma}$ rays observed by the segmented MINIBALL array. Coulomb excitation cross sections of the beam have been obtained by normalization to the well known Coulomb excitation cross sections of the $^{104}\mathrm{Pd}$ target.Results: The observation of three $\ensuremath{\gamma}$-ray transitions in $^{26}\mathrm{Na}$ together with available spectroscopic data allows us to determine $E2$- and $M1$-transitional matrix elements. Results are compared to theoretical predictions.Conclusion: The improved theoretical description of $^{26}\mathrm{Na}$ could be validated. Remaining discrepancies between experimental data and theoretical predictions indicate the need for future experiments and possibly further theoretical improvements.

Published
2015
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49. Cluster-transfer reactions with radioactive beams: A spectroscopic tool for neutron-rich nuclei

Author

J. Elseviers, H. De Witte, W. Krolas, S. Bottoni, R. Raabe, D. Voulot, F. Wenander, F. Flavigny, C. Bauer, N. Warr, S. Leoni, E. Rapisarda, R. Orlandi, P. Reiter, D. L. Balabanski, Magda Kowalska, Georgi P. Georgiev, A. Bracco, F. C. L. Crespi, G. Benzoni, M. J. Vermeulen, B. Szpak, B. Fornal, B. Siebeck, M. Seidlitz, R. V. F. Janssens, S. Hellgartner, P. Bednarczyk, D. Mücher, J. Bouma, M. Callens, A. Maj, Janne Pakarinen, A. I. Morales, N. Cieplicka-Oryńczak, K. Rusek, M L Lozano Benito, Michele Sferrazza, 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), CSNSM SNO, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), and 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)

Subjects
Physics, [PHYS]Physics [physics], cluster-transfer reactions, Nuclear and High Energy Physics, Reaction mechanism, Spins, ta114, radioactive beams, REX-ISOLDE, LI-7, Coulomb barrier, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Physique atomique et nucléaire, FUSION, BREAKUP, Cluster (physics), Neutron, LI-6, Atomic physics, Born approximation, Nuclear Experiment, Excitation, Direct process
Abstract

An exploratory experiment performed at REX-ISOLDE to investigate cluster-transfer reactions with radioactive beams in inverse kinematics is presented. The aim of the experiment was to test the potential of cluster-transfer reactions at the Coulomb barrier as a mechanism to explore the structure of exotic neutron-rich nuclei. The reactions Li7(Rb98,αxn) and Li7(Rb98,txn) were studied through particle-γ coincidence measurements, and the results are presented in terms of the observed excitation energies and spins. Moreover, the reaction mechanism is qualitatively discussed as a transfer of a clusterlike particle within a distorted-wave Born approximation framework. The results indicate that cluster-transfer reactions can be described well as a direct process and that they can be an efficient method to investigate the structure of neutron-rich nuclei at medium-high excitation energies and spins., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2015
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50. Deformation and mixing of coexisting shapes in neutron-deficient polonium isotopes

Author

R. Lutter, J. E. García-Ramos, D. Di Julio, E. Rapisarda, H. De Witte, T. Kröll, Mark Huyse, M. Bender, J. Iwanicki, K. Wrzosek-Lipska, R. Gernhäuser, N. Lecesne, Tuomas Grahn, Pauli Peura, Paul-Henri Heenen, Jan Diriken, V. Bildstein, M. Sferrazza, L. Próchniak, Thomas Elias Cocolios, Kristiaan Heyde, P. Reiter, E. Piselli, M. Sjödin, Iain Darby, Fredrik Wenander, A. Blazhev, Kalle Auranen, Ulrika Jakobsson, Janne Pakarinen, Joonas Konki, M. Seidlitz, C. Bauer, M. J. Vermeulen, B. Siebeck, N. Kesteloot, B. Bastin, E. Traykov, M. Zielinska, Marcus Scheck, Emyr Clement, C. Fransen, Panu Rahkila, D. Voulot, Liam Gaffney, B. Laurent, A. Damyanova, S. Bönig, J. Van de Walle, N. Warr, H. Törnqvist, P. Van Duppen, N. Bree, Herbert Hess, Kathrin Wimmer, 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), 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), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, REX-ISOLDE, Helsinki Institute of Physics, 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), and 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)

Subjects
CHARGE RADII, Nuclear and High Energy Physics, TRANSITION-PROBABILITY, chemistry.chemical_element, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, 114 Physical sciences, symbols.namesake, Matrix (mathematics), NUCLEAR-DATA SHEETS, COULOMB-EXCITATION, 0103 physical sciences, STATE PROPERTIES, Nuclear Physics - Experiment, Neutron, fysiikka, 010306 general physics, EVEN-EVEN NUCLIDES, Mixing (physics), isotopes, Polonium, INTRUDER STATES, GAMMA-RAY SPECTROSCOPY, Physics, SPIN STATES, isotoopit, PO ISOTOPES, Isotope, ta114, 010308 nuclear & particles physics, Bohr model, chemistry, Physics and Astronomy, symbols, Atomic physics, Interacting boson model, physics, polonium, 25.70.De, 23.20.Js, 25.60.−t, 27.80.+w
Abstract

Coulomb-excitation experiments are performed with postaccelerated beams of neutron-deficient Po196,198,200,202 isotopes at the REX-ISOLDE facility. A set of matrix elements, coupling the low-lying states in these isotopes, is extracted. In the two heaviest isotopes, Po200,202, the transitional and diagonal matrix elements of the 2+1 state are determined. In Po196,198 multistep Coulomb excitation is observed, populating the 4+1,0+2, and 2+2 states. The experimental results are compared to the results from the measurement of mean-square charge radii in polonium isotopes, confirming the onset of deformation from Po196 onwards. Three model descriptions are used to compare to the data. Calculations with the beyond-mean-field model, the interacting boson model, and the general Bohr Hamiltonian model show partial agreement with the experimental data. Finally, calculations with a phenomenological two-level mixing model hint at the mixing of a spherical structure with a weakly deformed rotational structure., We acknowledge the support of the ISOLDE Collaboration and technical teams and, especially, the support of RILIS and REX. This work was supported by FWO-Vlaanderen (Belgium), by GOA/2010/010 (BOF KU Leuven), by the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12), by the European Commission within the Seventh Framework Programme through I3-ENSAR (Contract No. RII3-CT-2010-262010), by the German BMBF under Contract Nos. 05P12PKFNE, 06DA9036I 05P12RDCIA, and 05P12RDCIB, by the UK Science and Technology Facilities Council, by the Spanish MINECO under Project No. FIS2011-28738-C02-02, by Narodowe Centrum Nauki (Polish Center for Scientific Research) Grant No. UMO-2013/10/M/ST2/00427, by the Academy of Finland (Contract No. 131665), and by the European Commission through the Marie Curie Actions call PIEFGA-2008-219174 (J.P.).

Published
2015
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