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

Author

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

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

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

Published
2020
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2. Pairing-quadrupole interplay in the neutron-deficient tin nuclei: First lifetime measurements of low-lying states in 106,108Sn

Author

M. Siciliano, J.J. Valiente-Dobón, A. Goasduff, F. Nowacki, A.P. Zuker, D. Bazzacco, A. Lopez-Martens, E. Clément, G. Benzoni, T. Braunroth, F.C.L. Crespi, N. Cieplicka-Oryńczak, M. Doncel, S. Ertürk, G. de France, C. Fransen, A. Gadea, G. Georgiev, A. Goldkuhle, U. Jakobsson, G. Jaworski, P.R. John, I. Kuti, A. Lemasson, T. Marchi, D. Mengoni, C. Michelagnoli, T. Mijatović, C. Müller-Gatermann, D.R. Napoli, J. Nyberg, M. Palacz, R.M. Pérez-Vidal, B. Sayği, D. Sohler, S. Szilner, D. Testov, M. Zielińska, D. Barrientos, B. Birkenbach, H.C. Boston, A.J. Boston, B. Cederwall, J. Collado, D.M. Cullen, P. Désesquelles, C. Domingo-Pardo, J. Dudouet, J. Eberth, F.J. Egea-Canet, V. González, L.J. Harkness-Brennan, H. Hess, D.S. Judson, A. Jungclaus, W. Korten, M. Labiche, A. Lefevre, S. Leoni, H. Li, A. Maj, R. Menegazzo, B. Million, A. Pullia, F. Recchia, P. Reiter, M.D. Salsac, E. Sanchis, O. Stezowski, and Ch. Theisen

Subjects
Lifetime, Nuclear structure, Multi-nucleon transfer, Light Sn, Tracking array, Physics, QC1-999
Abstract

The lifetimes of the low-lying excited states 2+ and 4+ have been directly measured in the neutron-deficient 106,108Sn isotopes. The nuclei were populated via a deep-inelastic reaction and the lifetime measurement was performed employing a differential plunger device. The emitted γ rays were detected by the AGATA array, while the reaction products were uniquely identified by the VAMOS++ magnetic spectrometer. Large-Scale Shell-Model calculations with realistic forces indicate that, independently of the pairing content of the interaction, the quadrupole force is dominant in the B(E2;21+→0g.s.+) values and it describes well the experimental pattern for 104−114Sn; the B(E2;41+→21+) values, measured here for the first time, depend critically on a delicate pairing-quadrupole balance, disclosed by the very precise results in 108Sn.

Published
2020
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3. Evidence of octupole-phonons at high spin in 207Pb

Author

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

Subjects
Physics, QC1-999
Abstract

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

Published
2019
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4. Isospin dependence of electromagnetic transition strengths among an isobaric triplet

Author

A. Boso, S.A. Milne, M.A. Bentley, F. Recchia, S.M. Lenzi, D. Rudolph, M. Labiche, X. Pereira-Lopez, S. Afara, F. Ameil, T. Arici, S. Aydin, M. Axiotis, D. Barrientos, G. Benzoni, B. Birkenbach, A.J. Boston, H.C. Boston, P. Boutachkov, A. Bracco, A.M. Bruce, B. Bruyneel, B. Cederwall, E. Clement, M.L. Cortes, D.M. Cullen, P. Désesquelles, Zs. Dombràdi, C. Domingo-Pardo, J. Eberth, C. Fahlander, M. Gelain, V. González, P.R. John, J. Gerl, P. Golubev, M. Górska, A. Gottardo, T. Grahn, L. Grassi, T. Habermann, L.J. Harkness-Brennan, T.W. Henry, H. Hess, I. Kojouharov, W. Korten, N. Lalović, M. Lettmann, C. Lizarazo, C. Louchart-Henning, R. Menegazzo, D. Mengoni, E. Merchan, C. Michelagnoli, B. Million, V. Modamio, T. Moeller, D.R. Napoli, J. Nyberg, B.S. Nara Singh, H. Pai, N. Pietralla, S. Pietri, Zs. Podolyak, R.M. Perez Vidal, A. Pullia, D. Ralet, G. Rainovski, M. Reese, P. Reiter, M.D. Salsac, E. Sanchis, L.G. Sarmiento, H. Schaffner, L.M. Scruton, P.P. Singh, C. Stahl, S. Uthayakumaar, J.J. Valiente-Dobón, and O. Wieland

Subjects
Physics, QC1-999
Abstract

Electric quadrupole matrix elements, Mp, for the Jπ=2+→0+, ΔT=0, T=1 transitions across the A=46 isobaric multiplet 46Cr-46V-46Ti have been measured at GSI with the FRS-LYCCA-AGATA setup. This allows direct insight into the isospin purity of the states of interest by testing the linearity of Mp with respect to Tz. Pairs of nuclei in the T=1 triplet were studied using identical reaction mechanisms in order to control systematic errors. The Mp values were obtained with two different methodologies: (i) a relativistic Coulomb excitation experiment was performed for 46Cr and 46Ti; (ii) a “stretched target” technique was adopted here, for the first time, for lifetime measurements in 46V and 46Ti. A constant value of Mp across the triplet has been observed. Shell-model calculations performed within the fp shell fail to reproduce this unexpected trend, pointing towards the need of a wider valence space. This result is confirmed by the good agreement with experimental data achieved with an interaction which allows excitations from the underlying sd shell. A test of the linearity rule for all published data on complete T=1 isospin triplets is presented.

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

Author

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

Subjects
Physics, QC1-999
Abstract

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

Published
2014
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7. Evidence of Partial Seniority Conservation in the πg_{9/2} Shell for the N=50 Isotones

Author

R M, Pérez-Vidal, A, Gadea, C, Domingo-Pardo, A, Gargano, J J, Valiente-Dobón, E, Clément, A, Lemasson, L, Coraggio, M, Siciliano, S, Szilner, M, Bast, T, Braunroth, J, Collado, A, Corina, A, Dewald, M, Doncel, J, Dudouet, G, de France, C, Fransen, V, González, T, Hüyük, B, Jacquot, P R, John, A, Jungclaus, Y H, Kim, A, Korichi, M, Labiche, S, Lenzi, H, Li, J, Ljungvall, A, López-Martens, D, Mengoni, C, Michelagnoli, C, Müller-Gatermann, D R, Napoli, A, Navin, B, Quintana, D, Ramos, M, Rejmund, E, Sanchis, J, Simpson, O, Stezowski, D, Wilmsen, M, Zielińska, A J, Boston, D, Barrientos, P, Bednarczyk, G, Benzoni, B, Birkenbach, H C, Boston, A, Bracco, B, Cederwall, D M, Cullen, F, Didierjean, J, Eberth, A, Gottardo, J, Goupil, L J, Harkness-Brennan, H, Hess, D S, Judson, A, Kaşkaş, W, Korten, S, Leoni, R, Menegazzo, B, Million, J, Nyberg, Zs, Podolyak, A, Pullia, D, Ralet, F, Recchia, P, Reiter, K, Rezynkina, M D, Salsac, M, Şenyiğit, D, Sohler, Ch, Theisen, D, Verney, Ministerio de Ciencia e Innovación (España), Generalitat Valenciana, European Commission, Department of Energy (US), Croatian Science Foundation, and Pérez-Vidal, R.M.

Abstract

7 pags., 3 figs., 1 tab., The reduced transition probabilities for the 4_{1}^{+}→2_{1}^{+} and 2_{1}^{+}→0_{1}^{+} transitions in ^{92}Mo and ^{94}Ru and for the 4_{1}^{+}→2_{1}^{+} and 6_{1}^{+}→4_{1}^{+} transitions in ^{90}Zr have been determined in this experiment making use of a multinucleon transfer reaction. These results have been interpreted on the basis of realistic shell-model calculations in the f_{5/2}, p_{3/2}, p_{1/2}, and g_{9/2} proton valence space. Only the combination of extensive lifetime information and large scale shell-model calculations allowed the extent of the seniority conservation in the N=50 g_{9/2} orbital to be understood. The conclusion is that seniority is largely conserved in the first πg_{9/2} orbital., This work was partially supported by MCIN/AEI/10.13039/501100011033 and Generalitat Valenciana, Spain, under Grants No. FPA2017-84756-C4, No. PID2020–118265GB-C4, and No. PROMETEO 2019/005, by the EU FEDER funds, by the European Union’s Horizon 2020 research and innovation program under Grant Agreement No. n654002, by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357, by STFC(UK) and by the Croatian Science Foundation under Projects No. 7194 and No. IP-2018-01-1257.

Published
2022

8. Evidence of Partial Seniority Conservation in the πg9/2 Shell for the N=50 Isotones

Author

R. M. Pérez-Vidal, A. Gadea, C. Domingo-Pardo, A. Gargano, J. J. Valiente-Dobón, E. Clément, A. Lemasson, L. Coraggio, M. Siciliano, S. Szilner, M. Bast, T. Braunroth, J. Collado, A. Corina, A. Dewald, M. Doncel, J. Dudouet, G. de France, C. Fransen, V. González, T. Hüyük, B. Jacquot, P. R. John, A. Jungclaus, Y. H. Kim, A. Korichi, M. Labiche, S. Lenzi, H. Li, J. Ljungvall, A. López-Martens, D. Mengoni, C. Michelagnoli, C. Müller-Gatermann, D. R. Napoli, A. Navin, B. Quintana, D. Ramos, M. Rejmund, E. Sanchis, J. Simpson, O. Stezowski, D. Wilmsen, M. Zielińska, A. J. Boston, D. Barrientos, P. Bednarczyk, G. Benzoni, B. Birkenbach, H. C. Boston, A. Bracco, B. Cederwall, D. M. Cullen, F. Didierjean, J. Eberth, A. Gottardo, J. Goupil, L. J. Harkness-Brennan, H. Hess, D. S. Judson, A. Kaşkaş, W. Korten, S. Leoni, R. Menegazzo, B. Million, J. Nyberg, Zs. Podolyak, A. Pullia, D. Ralet, F. Recchia, P. Reiter, K. Rezynkina, M. D. Salsac, M. Şenyiğit, D. Sohler, Ch. Theisen, and D. Verney

Subjects
General Physics and Astronomy
Published
2022

9. Evidence for spherical-oblate shape coexistence in Tc-87

Author

X. Liu, B. Cederwall, C. Qi, R. A. Wyss, Ö. Aktas, A. Ertoprak, W. Zhang, E. Clément, G. de France, D. Ralet, A. Gadea, A. Goasduff, G. Jaworski, I. Kuti, B. M. Nyakó, J. Nyberg, M. Palacz, R. Wadsworth, J. J. Valiente-Dobón, H. Al-Azri, A. Ataç Nyberg, T. Bäck, G. de Angelis, M. Doncel, J. Dudouet, A. Gottardo, M. Jurado, J. Ljungvall, D. Mengoni, D. R. Napoli, C. M. Petrache, D. Sohler, J. Timár, D. Barrientos, P. Bednarczyk, G. Benzoni, B. Birkenbach, A. J. Boston, H. C. Boston, I. Burrows, L. Charles, M. Ciemala, F. C. L. Crespi, D. M. Cullen, P. Désesquelles, C. Domingo-Pardo, J. Eberth, N. Erduran, S. Ertürk, V. González, J. Goupil, H. Hess, T. Huyuk, A. Jungclaus, W. Korten, A. Lemasson, S. Leoni, A. Maj, R. Menegazzo, B. Million, R. M. Perez-Vidal, Zs. Podolyàk, A. Pullia, F. Recchia, P. Reiter, F. Saillant, M. D. Salsac, E. Sanchis, J. Simpson, O. Stezowski, C. Theisen, M. Zielińska, Swedish Research Council, Science and Technology Facilities Council (UK), National Science Centre (Poland), National Research, Development and Innovation Office (Hungary), Ministerio de Ciencia e Innovación (España), Generalitat Valenciana, China Scholarship Council, and Liu, X.

Subjects
Subatomär fysik, Atom and Molecular Physics and Optics, Subatomic Physics, Atom- och molekylfysik och optik
Abstract

6 pags., 8 figs., 1 tab., Excited states in the neutron-deficient nucleus Tc87 have been studied via the fusion-evaporation reaction Fe54(Ar36,2n1p)Tc87 at 115 MeV beam energy. The AGATA γ-ray spectrometer coupled to the DIAMANT, NEDA, and Neutron Wall detector arrays for light-particle detection was used to measure the prompt coincidence of γ rays and light particles. Six transitions from the deexcitation of excited states belonging to a new band in Tc87 were identified by comparing γ-ray intensities in the spectra gated under different reaction channel selection conditions. The constructed level structure was compared with the shell model and total Routhian surface calculations. The results indicate that the new band structure in Tc87 is built on a spherical configuration, which is different from that assigned to the previously identified oblate yrast rotational band., This work was supported by the Swedish Research Council under Grants No. 621-2014-5558 and No. 2019-04880; the EU 7th Framework Programme, Integrating Activities Transnational Access, Project No. 262010 ENSAR; the UK STFC under Grants No. ST/L005727/1 and No. ST/P003885/1; the Polish National Science Centre, Grants No. 2016/22/M/ST2/00269 and No. 2017/25/B/ST2/01569; COPIN-INFN, COPIN-IN2P3, and COPIGAL projects; the National Research, Development and Innovation Fund of Hungary (Project No. K128947); the European Regional Development Fund (Contract No. GINOP-2.3.3-15-2016-00034); the Hungarian National Research, Development and Innovation Office, NKFIH, Contract No. PD124717; the Ministerio de Ciencia e Innovación and Generalitat Valenciana, Spain, under the Grants No. SEV-2014-0398 and No. FPA2017-84756-C4; PROMETEO/2019/005; and by the EU FEDER funds. X.L. gratefully acknowledges support from the China Scholarship Council, Grant No. 201700260183, for his stay in Sweden. We acknowledge the support from the AGATA Collaboration and thank the GANIL staff for excellent technical support and operation

Published
2022

10. Reinterpretation of excited states in Po212 : Shell-model multiplets rather than α -cluster states

Author

B. Million, E. Dupont, Bertrand Jacquot, R. Menegazzo, M. Ciemala, M. Zielińska, R. M. Perez-Vidal, L. J. Harkness-Brennan, D. Mengoni, Vicente González, W. Korten, D. Kocheva, D. Ralet, D. R. Napoli, P. Reiter, J. Eberth, Zs. Podolyák, A. Astier, B. Birkenbach, C. Michelagnoli, G. Tocabens, A. Perea, J. Dudouet, Ch. Lorenz, A. Bracco, A. Maj, M. Jurado, Begoña Quintana, A. Fernández, H. C. Boston, J. Ropert, J. Ljungvall, L. Ménager, Dirk Rudolph, G. Benzoni, H. Naïdja, E. Nácher, A. Korichi, A. Jungclaus, K. Wimmer, J. J. Valiente-Dobón, C. Houarner, A. Gadea, Johan Nyberg, J. Collado, A. Pullia, A. Gargano, Hans-Jurgen E. Hess, A. J. Boston, Emyr Clement, J. Goupil, A. Såmark-Roth, Enrique Sanchis, Diego Barrientos, S. Leoni, G. Frémont, N. Lalović, F. Saillant, D. S. Judson, O. Stezowski, A. Lemasson, C. Spitaels, S. Ansari, G. S. Simpson, D. M. Cullen, A. Illana, N. Redon, Luis Sarmiento, C. M. Petrache, G. Rainovski, Ch. Theisen, H. J. Li, C. Domingo-Pardo, and Pavel Golubev

Subjects
Reinterpretation, Physics, 010308 nuclear & particles physics, Excited state, 0103 physical sciences, SHELL model, Cluster (physics), Atomic physics, 010306 general physics, 01 natural sciences
Published
2021

11. Evidence for enhanced neutron-proton correlations from the level structure of the N=Z+1 nucleus Tc444387

Author

X. Liu, B. Cederwall, C. Qi, R. A. Wyss, Ö. Aktas, A. Ertoprak, W. Zhang, E. Clément, G. de France, D. Ralet, A. Gadea, A. Goasduff, G. Jaworski, I. Kuti, B. M. Nyakó, J. Nyberg, M. Palacz, R. Wadsworth, J. J. Valiente-Dobón, H. Al-Azri, A. Ataç Nyberg, T. Bäck, G. de Angelis, M. Doncel, J. Dudouet, A. Gottardo, M. Jurado, J. Ljungvall, D. Mengoni, D. R. Napoli, C. M. Petrache, D. Sohler, J. Timár, D. Barrientos, P. Bednarczyk, G. Benzoni, B. Birkenbach, A. J. Boston, H. C. Boston, I. Burrows, L. Charles, M. Ciemala, F. C. L. Crespi, D. M. Cullen, P. Désesquelles, C. Domingo-Pardo, J. Eberth, N. Erduran, S. Ertürk, V. González, J. Goupil, H. Hess, T. Huyuk, A. Jungclaus, W. Korten, A. Lemasson, S. Leoni, A. Maj, R. Menegazzo, B. Million, R. M. Perez-Vidal, Zs. Podolyàk, A. Pullia, F. Recchia, P. Reiter, F. Saillant, M. D. Salsac, E. Sanchis, J. Simpson, O. Stezowski, C. Theisen, and M. Zielińska

Subjects
Physics, Proton, Spectrometer, 010308 nuclear & particles physics, Isoscalar, Nuclear Theory, 01 natural sciences, Charged particle, Excited state, 0103 physical sciences, Level structure, Neutron, AGATA, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

The low-lying excited states in the neutron-deficient $N = Z + 1$ nucleus $^{87}_{43}$Tc$_{44}$ have been studied via the fusion-evaporation reaction $^{54}$Fe $(^{36}Ar, 2n1p)$ $^{87}$Tc at the Grand Accelerateur National d'Ions Lourds (GANIL), France. The AGATA spectrometer was used in conjunction with the auxiliary NEDA, Neutron Wall, and DIAMANT detector arrays to measure coincident prompt γ rays, neutrons, and charged particles emitted in the reaction. A level scheme of $^{87}$Tc from the $(9/2^+_{g.s})$ state to the $( 33 / 2^+_1$) state was established based on six mutually coincident γ -ray transitions. The constructed level structure exhibits a rotational behavior with a sharp backbending at $ℏω ≈ 0.50$ MeV. A decrease in alignment frequency and increase in alignment sharpness in the odd-mass isotonic chains around $N=44$ is proposed as an effect of the enhanced isoscalar neutron-proton interactions in odd-mass nuclei when approaching the $N=Z$ line.

Published
2021

12. Lifetime measurements of excited states in neutron-rich Ti53 : Benchmarking effective shell-model interactions

Author

A. Vogt, C. Müller-Gatermann, D. Ralet, A. Dewald, A. Goldkuhle, C. Michelagnoli, Y.H. Kim, K. O. Zell, Herbert Hess, Hongzhen Li, Emyr Clement, C. Fransen, B. Birkenbach, P. Reiter, S. M. Lenzi, A. Blazhev, J. Litzinger, J. Jolie, R. M. Pérez-Vidal, J. Dudouet, B. S. Nara Singh, N. Warr, J. Eberth, Thomas Braunroth, A. Lemasson, B. Jacquot, and M. Beckers

Subjects
Physics, Spectrometer, 010308 nuclear & particles physics, Yrast, Nuclear structure, Shell (structure), 01 natural sciences, 7. Clean energy, Particle identification, Recoil, Excited state, 0103 physical sciences, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

Level lifetimes of the yrast (5/2(-)) to 13/2(-) states in the neutron-rich nucleus Ti-53, produced in a multinucleon-transfer reaction, have been measured for the first time. The recoil distance Doppler-shift method was employed and lifetimes of the excited states were extracted by a lineshape analysis aided by GEANT4-based Monte-Carlo simulations. The experiment was performed at the Grand Accelerateur National d'Ions Lourds facility in Caen, France, by using the Advanced Gamma Tracking Array for the gamma-ray detection coupled to the large-acceptance variable mode spectrometer for an event-by-event particle identification and the Cologne plunger for deep-inelastic reactions. Reduced transition probabilities, deduced from the lifetimes, give new information on the nuclear structure of Ti-53, and are used to benchmark different shell-model calculations using established interactions in the f p shell.

Published
2020

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

Author

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

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

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

Published
2020

14. Isospin Properties of Nuclear Pair Correlations from the Level Structure of the Self-Conjugate Nucleus Ru88

Author

Eric Clément, B. Birkenbach, M. Zielińska, B. Million, M. Doncel, C. Domingo-Pardo, F. Recchia, J. Ljungvall, R. M. Perez-Vidal, Torbjörn Bäck, P. Reiter, P. Bednarczyk, J. Simpson, D. Mengoni, J. J. Valiente-Dobón, A. Lemasson, W. Korten, W. Zhang, X. Liu, B. M. Nyako, A. J. Boston, J. Goupil, H. Al-Azri, Diego Barrientos, M. D. Salsac, F. C. L. Crespi, A. Jungclaus, A. Gadea, A. Maj, N. Erduran, P. Désesquelles, A. Gottardo, Ch. Theisen, T. Hüyük, János Timár, Alberto Pullia, Vicente González, L. Charles, Zs. Podolyák, R. Menegazzo, C. M. Petrache, D. M. Cullen, S. Erturk, A. Ataç Nyberg, M. Jurado, Herbert Hess, Chong Qi, O. Aktas, Bo Cederwall, István Kuti, D. R. Napoli, Johan Nyberg, Alain Goasduff, D. Ralet, Enrique Sanchis, A. Ertoprak, M. Palacz, F. Saillant, D. Sohler, O. Stezowski, R. Wadsworth, J. Dudouet, G. de Angelis, M. Ciemala, G. Jaworski, J. Eberth, H. C. Boston, G. Benzoni, I. Burrows, and S. Leoni

Subjects
Physics, Isovector, Isoscalar, Nuclear Theory, General Physics and Astronomy, 01 natural sciences, Charged particle, Nuclear physics, 13. Climate action, Isospin, Excited state, 0103 physical sciences, Neutron detection, AGATA, Neutron, Nuclear Experiment, 010306 general physics
Abstract

The low-lying energy spectrum of the extremely neutron-deficient self-conjugate (N = Z) nuclide 88 44Ru44 has been measured using the combination of the Advanced Gamma Tracking Array (AGATA) spectrometer, the NEDA and Neutron Wall neutron detector arrays, and the DIAMANT charged particle detector array. Excited states in 88Ru were populated via the 54Fe(36Ar; 2n )88Ru fusion-evaporation reaction at the Grand Acc�el�erateur National d'Ions Lourds (GANIL) accelerator complex. The observed -ray cascade is assigned to 88Ru using clean prompt - -2-neutron coincidences in anti-coincidence with the detection of charged particles, con�rming and extending the previously assigned sequence of low-lying excited states. It is consistent with a moderately deformed rotating system exhibiting a band crossing at a rotational frequency that is significantly higher than standard theoretical predictions with isovector pairing, as well as observations in neighboring N > Z nuclides. The direct observation of such a \delayed" rotational alignment in a deformed N = Z nucleus is in agreement with theoretical predictions related to the presence of strong isoscalar neutron-proton pair correlations.

Published
2020

15. Shape coexistence in neutron-deficient Hg188 investigated via lifetime measurements

Author

P. R. John, J. J. Valiente-Dobón, M. Zielińska, J. Pakarinen, I. Deloncle, A. Boso, B. Melon, D. Mengoni, D. A. Testov, B. de Canditiis, R. Menegazzo, Thomas Braunroth, A. Goasduff, S. M. Lenzi, Sophie Péru, A. Nannini, I. Zanon, G. Jaworski, G. de Angelis, A. Gadea, D. R. Napoli, F. Galtarossa, N. Cieplicka-Oryńczak, A. Vogt, B. Birkenbach, D. Ashad, F. Recchia, Liam Gaffney, G. Benzoni, W. Witt, D. Quero, D. Bazzacco, A. Gozzelino, P. Koseoglou, K. Hadyńska-Klȩk, F. Davide, M. Siciliano, P. K. Rath, J. Wiederhold, J. Libert, Magda Cicerchia, G. Colucci, Tomás R. Rodríguez, and M. Rocchini

Subjects
Physics, Spectrometer, Isotope, 010308 nuclear & particles physics, Nuclear structure, chemistry.chemical_element, 01 natural sciences, 7. Clean energy, Molecular physics, symbols.namesake, medicine.anatomical_structure, chemistry, Excited state, 0103 physical sciences, medicine, symbols, Neutron, 010306 general physics, Hamiltonian (quantum mechanics), Nucleus, Polonium
Abstract

Background: Shape coexistence in the Z≈82 region has been established in mercury, lead, and polonium isotopes. For even-even mercury isotopes with 100≤N≤106 multiple fingerprints of this phenomenon are observed, which seems to be no longer present for N≥110. According to a number of theoretical calculations, shape coexistence is predicted in the Hg188 isotope. Purpose: The aim of this work was to measure lifetimes of excited states in Hg188 to infer their collective properties, such as the deformation. Extending the investigation to higher-spin states, which are expected to be less affected by band-mixing effects, can provide additional information on the coexisting structures. Methods: The Hg188 nucleus was populated using two different fusion-evaporation reactions with two targets, Gd158 and Gd160, and a beam of S34 provided by the Tandem-ALPI accelerator complex at the Laboratori Nazionali di Legnaro. The channels of interest were selected using the information from the Neutron Wall array, while the γ rays were detected using the GALILEO γ-ray spectrometer. Lifetimes of excited states were determined using the recoil-distance Doppler-shift method, employing the dedicated GALILEO plunger device. Results: Lifetimes of the states up to spin 16ℏ were measured and the corresponding reduced transition probabilities were calculated. Assuming two-band mixing and adopting, as done commonly, the rotational model, the mixing strengths and the deformation parameters of the unperturbed structures were obtained from the experimental results. In order to shed light on the nature of the observed configurations in the Hg188 nucleus, the extracted transition strengths were compared with those resulting from state-of-the-art beyond-mean-field calculations using the symmetry-conserving configuration-mixing approach, limited to axial shapes, and the five-dimensional collective Hamiltonian, including the triaxial degree of freedom. Conclusions: The first lifetime measurement for states with spin ≥6 suggested the presence of an almost spherical structure above the 121+ isomer and allowed elucidating the structure of the intruder band. The comparison of the extracted B(E2) strengths with the two-band mixing model allowed the determination of the ground-state band deformation. Both beyond-mean-field calculations predict coexistence of a weakly deformed band with a strongly prolate-deformed one, characterized by elongation parameters similar to those obtained experimentally, but the calculated relative position of the bands and their mixing strongly differ.

Published
2020

16. Low-lying electric dipole gamma-continuum for the unstable Fe-62,64 nuclei : Strength evolution with neutron number

Author

Eric Clément, B. Birkenbach, A. I. Morales, D. Bazzacco, H. J. Wollersheim, J. J. Valiente-Dobón, D. M. Cullen, L. J. Harkness-Brennan, M. Kmiecik, Alberto Pullia, C. Domingo-Pardo, Luis Sarmiento, C. Nociforo, N. Goel, B. Bruyneel, G. Rainovski, M.D. Salsac, S. Pietri, Begoña Quintana, J. Simpson, Pavel Golubev, T. Habermann, Johan Nyberg, R. Menegazzo, S. Leoni, M. Reese, V. Yu. Ponomarev, A. Maj, T. Arici, A. Gottardo, N. Kurz, M. Górska, S. Brambilla, I. Kojouharov, E. Merchan, M. L. Cortés, Stefano Riboldi, Enrique Sanchis, N. Lalović, Vicente González, R. Avigo, Norbert Pietralla, P. Reiter, F. Camera, M. Labiche, Zs. Podolyák, J. Gerl, D. Ralet, F. Ameil, Andreas Görgen, A. Gadea, A. Bracco, A. Jungclaus, G. Benzoni, O. Stezowski, Dirk Rudolph, D. Curien, J. Eberth, H. C. Boston, S. Bottoni, W. Korten, F. C. L. Crespi, N. Blasi, H. Schaffner, D. Mengoni, M. Lettmann, G. Duchêne, Diego Barrientos, P. H. Regan, F. Didierjean, M. Ciemala, P. Bednarczyk, G. Guastalla, B. Million, E. Gregor, Oliver Wieland, F. Recchia, D. R. Napoli, A. Atac, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Istituto Nazionale di Fisica Nucleare, Science and Technology Facilities Council (UK), Swedish Research Council, Federal Ministry of Education and Research (Germany), European Commission, Generalitat Valenciana, Ministerio de Economía y Competitividad (España), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Phonon, Astrophysics::High Energy Astrophysical Phenomena, Binding energy, Nuclear Theory, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, 64Fe, Dipole excitation around neutron threshold, 62Fe, Subatomär fysik, 0103 physical sciences, Subatomic Physics, ddc:530, Neutron, Nuclear Physics - Experiment, Nuclear structure, 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, 62 Fe, Fe, 64, 64 Fe, lcsh:QC1-999, Dipole, Fe-64, Neutron number, Fe-62, AGATA, Atomic physics, lcsh:Physics
Abstract

6 pags., 4 figs., The γ-ray emission from the nuclei Fe following Coulomb excitation at bombarding energy of 400-440 AMeV was measured with special focus on E1 transitions in the energy region 4-8 MeV. The unstable neutron-rich nuclei Fe were produced at the FAIR-GSI laboratories and selected with the FRS spectrometer. The γ decay was detected with AGATA. From the measured γ-ray spectra the summed E1 strength is extracted and compared to microscopic quasi-particle phonon model calculations. The trend of the E1 strength with increasing neutron number is found to be fairly well reproduced with calculations that assume a rather complex structure of the 1 states (three-phonon states) inducing a strong fragmentation of the E1 nuclear response below the neutron binding energy., This work was partially supported by INFN (Italy) and STFC (UK), the Swedish Research Council (Vetenskapsrådet, VR 2010-147, 2011-5253, and 2016-3969), BMBF NuSTAR-AGATA 05P18RDFN9 and BMBF NuSTAR 05P18RDFN1. The project was co-funded by the European Commission under the 7th Framework Program for RTD (2007-2013) under the Capacities Program (Contract Number 262010, ENSAR). This work was par-tially supported by the Ministry of Science, and Generalitat Valenciana, Spain, under the Grants SEV-2014-0398, FPA2017-84756-C4, PROMETEO/2019/005 and by the EU FEDER funds.

Published
2020

17. Pairing-quadrupole interplay in the neutron-deficient tin nuclei: First lifetime measurements of low-lying states in 106,108Sn

Author

R. M. Perez-Vidal, T. Marchi, P. Reiter, Georgi P. Georgiev, Andrés P. Zuker, C. Fransen, D. Mengoni, J. Dudouet, Bo Cederwall, C. Theisen, C. Domingo-Pardo, Thomas Braunroth, A. Goasduff, O. Stezowski, W. Korten, F. C. L. Crespi, A. J. Boston, Johan Nyberg, C. Michelagnoli, B. Birkenbach, Vicente González, C. Müller-Gatermann, Tea Mijatović, D. Bazzacco, Hui Li, Enrique Sanchis, D. S. Judson, N. Cieplicka-Oryńczak, B. Million, Diego Barrientos, S. Leoni, M. Labiche, L. J. Harkness-Brennan, A. Jungclaus, F. Recchia, D. Testov, F.J. Egea-Canet, Herbert Hess, J. Eberth, H. C. Boston, A. Lefevre, J. Collado, István Kuti, A. Lemasson, Dóra Sohler, Alberto Pullia, M. D. Salsac, M. Siciliano, A. Gadea, D. R. Napoli, G. Jaworski, A. Lopez-Martens, S. Szilner, G. Benzoni, Maria Doncel, Eric Clément, M. Palacz, P. R. John, M. Zielińska, P. Désesquelles, B. Sayği, Ulrika Jakobsson, J. J. Valiente-Dobón, A. Maj, R. Menegazzo, S. Erturk, F. Nowacki, D. M. Cullen, A. Goldkuhle, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Ege Üniversitesi, Ministerio de Ciencia e Innovación (España), Generalitat Valenciana, Université de Strasbourg (UNISTRA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear and High Energy Physics, Light Sn, chemistry.chemical_element, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, 01 natural sciences, Subatomär fysik, Lifetime, Multi-nucleon transfer, Nuclear structure, Tracking array, 0103 physical sciences, Subatomic Physics, Neutron, Nuclear Physics - Experiment, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Spectrometer, Isotope, 010308 nuclear & particles physics, lcsh:QC1-999, chemistry, Pairing, Excited state, Quadrupole, AGATA, Atomic physics, Tin, lcsh:Physics
Abstract

The lifetimes of the low-lying excited states 2(+) and 4(+) have been directly measured in the neutron-deficient Sn-106,Sn-108 isotopes. the nuclei were populated via a deep-inelastic reaction and the lifetime measurement was performed employing a differential plunger device. the emitted gamma rays were detected by the AGATA array, while the reaction products were uniquely identified by the VAMOS++ magnetic spectrometer. Large-Scale Shell-Model calculations with realistic forces indicate that, independently of the pairing content of the interaction, the quadrupole force is dominant in the B(E2; 2(1)(+) -> 0(g.s)(+)) values and it describes well the experimental pattern for Sn104-114 ; the B(E2;(+)(4) -> 2(1)(+)) values, measured here for the first time, depend critically on a delicate pairing-quadrupole balance, disclosed by the very precise results in Sn-108. (C) 2020 the Authors. Published by Elsevier B.V., European Union's Seventh Framework Programme for Research and Technological DevelopmentEuropean Union (EU) [262010]; Fondazione Cassa di Risparmio Padova e Rovigo under the project CONPHYT, starting grant in 2017; Swedish Research CouncilSwedish Research Council [822-2005-3332, 821-2010-6024, 821-2013-2304, 621-20145558, 2017-0065]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation [2005.0184]; Scientific and Technological Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [114F473]; Ministerio de Ciencia e InnovacionInstituto de Salud Carlos IIISpanish Government [SEV-2014-0398, FPA2017-84756-C4, EEBBI-15-09671]; Generalitat ValencianaGeneralitat Valenciana [PROMETEO/2019/005]; EU-FEDER fundsEuropean Union (EU); Croatian Science Foundation [7194]; Hungarian National Research and Innovation Office (NKFIH) [K128947, PD124717, GINOP-2.3.3-15-2016-00034]; Polish National Science Centre under the COPIN-IN2P3 project [2014-14-M-ST2-00738, 2016-22M-ST2-00269, 2017-25-B-ST2-01569]; Polish National Science Centre under the COPIGAL project [2014-14-M-ST2-00738, 2016-22M-ST2-00269, 2017-25-B-ST2-01569]; Polish National Science Centre under the POLITA project [2014-14-M-ST2-00738, 2016-22M-ST2-00269, 2017-25-B-ST2-01569], The authors would like to thank the AGATA and VAMOS collaborations. Special thanks go to the GANIL technical staff for their help in setting up the apparatuses and the good quality beam and to A. Poves for his fruitful comments. This work was partially supported by the European Union's Seventh Framework Programme for Research and Technological Development (grant no. 262010). A.G. acknowledges the support of the Fondazione Cassa di Risparmio Padova e Rovigo under the project CONPHYT, starting grant in 2017. the work was also supported (B.C, H.L., J.N. and U.J.) by Swedish Research Council under the grant agreements nos. 822-2005-3332, 821-2010-6024, 821-2013-2304, 621-20145558 and 2017-0065, and by the Knut and Alice Wallenberg Foundation grant no. 2005.0184, (B.S.) by the Scientific and Technological Council of Turkey (TUBITAK) under the project no. 114F473, (A.G., A.J. and R.P.) by the Ministerio de Ciencia e Innovacion under the contracts nos. SEV-2014-0398, FPA2017-84756-C4 and EEBBI-15-09671, by the Generalitat Valenciana under the grant agreement no. PROMETEO/2019/005 and by the EU-FEDER funds, (T.M and S.S.) by the Croatian Science Foundation under the project no. 7194, (I.K and D.S.) by the Hungarian National Research and Innovation Office (NKFIH) under the project nos. K128947, PD124717 and GINOP-2.3.3-15-2016-00034, (M.P.) by the Polish National Science Centre with the grants nos. 2014-14-M-ST2-00738, 2016-22M-ST2-00269 and 2017-25-B-ST2-01569 under the COPIN-IN2P3, COPIGAL and POLITA projects.

Published
2020

18. Benchmarking the PreSPEC@GSI experiment for Coulex-multipolarimetry on the $\pi (p_{3/2})\rightarrow \pi (p_{1/2})$ spin-flip transition in $^{85}$Br

Author

Diego Barrientos, M. Labiche, L. Grassi, J. Eberth, Claes Fahlander, V. Modamio, I. Kojouharov, B. Birkenbach, O. Möller, H. Egger, F. C. L. Crespi, P. Désesquelles, C. Domingo-Pardo, S. Afara, W. Korten, A. Bracco, B. S. Nara Singh, D. M. Cullen, Enrique Sanchis, M. Lettmann, Pavel Golubev, Oliver Wieland, J. Gerl, B. Bruyneel, G. Rainovski, Dirk Rudolph, A. Maj, Norbert Pietralla, A. Blazhev, P. R. John, A. Gottardo, D. Curien, P. Bednarczyk, B. Million, Luis Sarmiento, T. Arici, Pushpendra Singh, S. Aydin, E. Merchan, P. Reiter, F. Ameil, S. Pietri, J. Simpson, Eric Clément, J. Jolie, C. Stahl, K. A. Gladnishki, K. Moschner, Herbert Hess, A. J. Boston, D. Ralet, M. L. Cortés, N. Lalović, C. Louchart-Henning, M. A. Bentley, D. S. Judson, H. Schaffner, J. J. Valiente-Dobón, P. Boutachkov, Roberto Menegazzo, D. Mengoni, M. Reese, V. Werner, G. Duchêne, L. J. Harkness-Brennan, G. Benzoni, D. R. Napoli, Vicente González, F. Didierjean, Zs. Podolyák, T. Möller, C. Lizarazo, P. Napiralla, M. Górska, T. Habermann, D. G. Jenkins, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut de Physique Nucléaire d'Orsay (IPNO), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Hadron, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Transition strength, 0103 physical sciences, Nuclear fusion, AGATA, Spin-flip, 010306 general physics, Beam (structure)
Abstract

International audience; A first performance test of the Coulomb excitation multipolarimetry (Coulex-multipolarimetry) method is presented. It is based on a $^{85}\hbox {Br}\,\pi p_{3/2}\rightarrow \pi p_{1/2}$ spin-flip experiment performed as part of the PreSPEC-AGATA campaign at the GSI Helmholtzzentrum für Schwerionenforschung (GSI). Via determination of background levels around the expected $^{85}\hbox {Br}$ excitations as well as measured $^{197}\hbox {Au}$ excitations, an upper limit for the M1 transition strength of the $1/2_1^-\rightarrow 3/2_\text {g.s.}^-$ transition in $^{85}\hbox {Br}$ and a lower beam time limit for upcoming experimental campaigns utilizing Coulex-multipolarimetry have been inferred. The impact of the use of AGATA in its anticipated $1\pi $ configuration on these estimates is deduced via Geant4 simulations.

Published
2020

19. Lifetime measurements of excited states in neutron-rich Ti 53 : Benchmarking effective shell-model interactions

Author

A. Goldkuhle, A. Blazhev, C. Fransen, A. Dewald, M. Beckers, B. Birkenbach, T. Braunroth, E. Clément, J. Dudouet, J. Eberth, H. Hess, B. Jacquot, J. Jolie, Y.-H. Kim, A. Lemasson, S. M. Lenzi, H. J. Li, J. Litzinger, C. Michelagnoli, C. Müller-Gatermann, B. S. Nara Singh, R. M. Pérez-Vidal, D. Ralet, P. Reiter, A. Vogt, N. Warr, K. O. Zell

Published
2020
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20. Lifetime measurements in Ti52,54 to study shell evolution toward N=32

Author

A. Lemasson, W. Korten, Thomas Braunroth, Herbert Hess, C. Müller-Gatermann, C. Domingo-Pardo, J. Simpson, I. Burrows, S. Leoni, P. Reiter, C. Fransen, A. Vogt, Bertrand Jacquot, C. Houarner, D. M. Cullen, C. Henrich, A. Lefevre, A. Atac, M. Zielińska, M. Ciemala, N. Ménard, F. Legruel, A. J. Boston, J. Eberth, A. Goldkuhle, M. Labiche, H. C. Boston, Alberto Pullia, G. Voltolini, K. O. Zell, A. Korichi, J. Ljungvall, R. M. Pérez-Vidal, L. Ménager, J.-L. Foucher, C. Barthe-Dejean, C. Michelagnoli, Diego Barrientos, A. Dewald, J. Ropert, B. Birkenbach, Y. H. Kim, O. Stezowski, P. Bourgault, A. Blazhev, G. Frémont, J. Goupil, D. Ralet, Bo Cederwall, G. Benzoni, Ch. Theisen, N. Warr, A. Gadea, H. J. Li, A. Maj, Johan Nyberg, M. D. Salsac, S. M. Lenzi, M. Jean, J. J. Valiente Dobon, C. Maugeais, L. Legeard, P. Gangnant, A. Navin, M. Ozille, B. Million, M. Tripon, B. S. Nara Singh, Enrique Sanchis, D. R. Napoli, Emyr Clement, J. Dudouet, F. Saillant, Vicente González, F. Recchia, Ch. Schmitt, H. Munoz, Zs. Podolyák, B. Raine, M. Beckers, Roberto Menegazzo, D. Mengoni, J. Cacitti, J. Litzinger, J. Jolie, D. S. Judson, C. Spitaels, and M. Toulemonde

Subjects
Plunger, Physics, 010308 nuclear & particles physics, Excited state, Nuclear Theory, 0103 physical sciences, Shell (structure), Atomic physics, Nuclear Experiment, 010306 general physics, 7. Clean energy, 01 natural sciences
Abstract

Lifetimes of the excited states in the neutron-rich Ti-52,Ti-54 nuclei, produced in a multinucleon-transfer reaction, were measured by employing the Cologne plunger device and the recoil-distance D ...

Published
2019

21. Characterization and calibration of radiation-damaged double-sided silicon strip detectors

Author

P. Reiter, T. Steinbach, Herbert Hess, M. Seidlitz, K. Wolf, Norbert Pietralla, R. Hirsch, R. Lutter, T. Limböck, K. Arnswald, Klaus Meerholz, L. Kaya, A. Vogt, N. Warr, B. Birkenbach, and C. Stahl

Subjects
Physics, Nuclear and High Energy Physics, Silicon, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, business.industry, Radioactive source, Detector, chemistry.chemical_element, Radiation, 01 natural sciences, Charged particle, Optics, chemistry, 0103 physical sciences, Radiation damage, Calibration, Granularity, 010306 general physics, business, Instrumentation
Abstract

Double-sided silicon strip detectors (DSSSD) are commonly used for event-by-event identification of charged particles as well as the reconstruction of particle trajectories in nuclear physics experiments with stable and radioactive beams. Intersecting areas of both p- and n-doped front- and back-side segments form individual virtual pixel segments allowing for a high detector granularity. DSSSDs are employed in demanding experimental environments and have to withstand high count rates of impinging nuclei. The illumination of the detector is often not homogeneous. Consequently, radiation damage of the detector is distributed non-uniformly. Position-dependent incomplete charge collection due to radiation damage limits the performance and lifetime of the detectors, the response of different channels may vary drastically. Position-resolved charge-collection losses between front- and back-side segments are investigated in an in-beam experiment and by performing radioactive source measurements. A novel position-resolved calibration method based on mutual consistency of p-side and n-side charges yields a significant enhancement of the energy resolution and the performance of radiation-damaged parts of the detector.

Published
2017

22. 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

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

Author

B. Quintana Arnés, G. Bocchi, R. Perez, Raymond J. Carroll, W. Korten, Alberto Pullia, M. Labiche, Zs. Podolyák, A. Navin, Enrique Sanchis, F. Saillant, Norbert Pietralla, F. C. L. Crespi, C. M. Shand, E. Dupont, B. Fornal, D. Kocheva, Diego Barrientos, O. Stezowski, P. Reiter, L. Atanasova, M. Ciemala, Herbert Hess, Roberto Menegazzo, D. Mengoni, B. Birkenbach, J. Collado, H.J. Eberth, Bo Cederwall, D. Ralet, B. Million, A. Maj, P. Van Isacker, D. Wilmsen, J. J. Valiente Dobon, J. Dudouet, F. Recchia, P. Bednarczyk, M. Rejmund, Georgi P. Georgiev, Andrew Stuchbery, A. Goasduff, A. Lemasson, Deyan Yordanov, P. R. John, Salsac, R. L. Lozeva, A. Jungclaus, C. Michelagnoli, A. Blazhev, J. Goupil, S. Franchoo, A. Gadea, L. J. Harkness, Johan Nyberg, S. M. Lenzi, D. L. Balabanski, D. M. Cullen, I. Burrows, T. Konstantinopoulos, Emyr Clement, H. C. Boston, O. Wieland, C. Theisen, A. J. Boston, A. Kusoglu, C. Fransen, A. Korichi, S. Leoni, C. Müller-Gatermann, J. Ljungvall, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-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, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Ministerio de Economía y Competitividad (España), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Plunger device, Phonon, Nuclear Theory, Octupole phonon, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], gamma-Ray tracking, γ -Ray tracking, 01 natural sciences, 7. Clean energy, Recoil, VAMOS++ spectrometer, AGATA spectrometer, Nuclear deformation, γ-Ray tracking, 0103 physical sciences, Physics::Atomic Physics, Nuclear Experiment, 010306 general physics, Spin (physics), Physics, VAMOS plus plus spectrometer, 010308 nuclear & particles physics, lcsh:QC1-999, Atomic physics, lcsh:Physics
Abstract

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

Published
2019

24. Effects of one valence proton on seniority and angular momentum of neutrons in neutron-rich Sb51122–131 isotopes

Author

L. J. Harkness-Brennan, H. L. Crawford, Alberto Pullia, M. Rejmund, A. Jungclaus, B. Birkenbach, G. Benzoni, A. Lefevre, J. J. Valiente-Dobón, J. Goupil, Bo Cederwall, M. D. Salsac, P. Bednarczyk, Ch. Theisen, H. J. Li, A. J. Boston, R. Banik, Diego Barrientos, Vicente González, J. Eberth, O. Stezowski, Sumita Bhattacharyya, V. Morel, H. C. Boston, D. Ralet, D. Mengoni, A. Lemasson, D. M. Cullen, I. Stefan, Bertrand Jacquot, R. Menegazzo, D. R. Napoli, Herbert Hess, J. Collado, P. Fallon, J. Dudouet, C. Michelagnoli, R. Palit, G. Frémont, Y. H. Kim, S. Biswas, P. Désesquelles, R. M. Pérez-Vidal, M. Zielińska, Soumik Bhattacharya, A. Navin, Enrique Sanchis, F. Saillant, W. Korten, B. Million, J. Ropert, Begoña Quintana, J. Ljungvall, L. Ménager, Eric Clément, F. Recchia, A. Maj, M. Labiche, P. Reiter, and C. Domingo-Pardo

Subjects
Physics, Angular momentum, Valence (chemistry), Isotope, 010308 nuclear & particles physics, Fission, Nuclear Theory, Nuclear structure, 7. Clean energy, 01 natural sciences, Neutron number, 0103 physical sciences, AGATA, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

Background: Levels fulfilling the seniority scheme and relevant isomers are commonly observed features in semimagic nuclei; for example, in Sn isotopes (Z=50). Seniority isomers in Sn, with dominantly pure neutron configurations, directly probe the underlying neutron-neutron (νν) interaction. Furthermore, an addition of a valence proton particle or hole, through neutron-proton (νπ) interaction, affects the neutron seniority as well as the angular momentum. Purpose: Benchmark the reproducibility of the experimental observables, like the excitation energies (EX) and the reduced electric-quadrupole transition probabilities [B(E2)], with the results obtained from shell-model interactions for neutron-rich Sn and Sb isotopes with N

Published
2019

25. Preliminary results of lifetime measurements in neutron-rich $^{53}$Ti

Author

Bertrand Jacquot, Emmanuel Clément, Damian Ralet, M. Rejmund, B. Birkenbach, Thomas Braunroth, P. Reiter, Karl Oskar Zell, Rosa Maria Perez-Vidal, M. Beckers, C. Müller-Gatermann, M. Zielińska, Yung-Hee Kim, Caterine Michelagnoli, A. Vogt, N. Warr, S. M. Lenzi, A. Lemasson, A. Goldkuhle, C. Fransen, J. Ljungvall, Herbert Hess, D. R. Napoli, J. Eberth, Jérémie Dudouet, A. Blazhev, Hongjie Li, Navin Alahari, J. Litzinger, Bondili Sreenivasa Nara Singh, Alfred Dewald, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Spectrometer, Isotope, 010308 nuclear & particles physics, Yrast, QC1-999, Nuclear structure, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, Recoil, 0103 physical sciences, Neutron, AGATA, 010306 general physics, Nuclear Experiment, Beam (structure)
Abstract

To study the nuclear structure of neutron-rich titanium isotopes, a lifetime measurement was performed at the Grand Accélérateur National d'Ions Lourds (GANIL) facility in Caen, France. The nucleiwere produced in a multinucleon-transfer reaction by using a 6.76 MeV/u 238U beam. The Advanced Gamma Tracking Array (AGATA) was employed for the γ-ray detection and target-like recoils were identified event-by-event by the large-acceptance variable mode spectrometer (VAMOS++). Preliminary level lifetimes of the (5/2−) to 13/2− states of the yrast band in the neutron-rich nucleus 53Ti were measured for the first time employing the recoil distance Doppler-shift (RDDS) method and the compact plunger for deep inelastic reactions. The differential decay curve method (DDCM) was used to obtain the lifetimes from the RDDS data.

Published
2019

26. Pulse-Shape Analysis and position resolution in highly segmented HPGe AGATA detectors

Author

M. Zielińska, B. Birkenbach, P. Reiter, Herbert Hess, B. Bruyneel, C. Michelagnoli, Emyr Clement, R. M. Perez-Vidal, L. Lewandowski, J. Eberth, H. J. Li, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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, and 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)

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Preamplifier, Detector, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Statistical weight, 7. Clean energy, 01 natural sciences, Computational physics, Semiconductor detector, Position (vector), Rise time, 0103 physical sciences, Annihilation radiation, AGATA, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics
Abstract

International audience; The performance of the Pulse-Shape Analysis (PSA) in AGATA HPGe detectors was investigated and improved employing a $\gamma$ -ray source measurement based on $ e^{+}e^{-}$ annihilation radiation after decays of$^{22}$Na by $ \beta^{+}$ decay. The first interaction positions of the two 511keV $\gamma$ rays were determined and the connecting line of these two positions was compared to the known source position as a measure for the PSA performance. The position resolution and its dependence on the PSA parameters were investigated by varying most relevant input quantities: the charge carrier mobility of the holes, the response of the employed measuring electronics especially the preamplifier rise time. The relative statistical weight of charge signals and transient signals was scrutinized. The optimal distance metric of the grid-search algorithm and its impact on the position resolution were determined.

Published
2019

27. Identification of high-spin proton configurations in Ba136 and Ba137

Author

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

Subjects
Physics, Proton, Spins, Isotope, 010308 nuclear & particles physics, Nuclear structure, 01 natural sciences, 7. Clean energy, 0103 physical sciences, AGATA, Atomic physics, 010306 general physics, Spin (physics), Spectroscopy, Excitation
Abstract

The high-spin structures of 136Ba and 137Ba are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. 136Ba is populated in a 136Xe+238U MNT reaction employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and in two 9Be + 130Te fusion-evaporation reactions using the High-efficiency Observatory for -Ray Unique Spectroscopy (HORUS) at the FN tandem accelerator of the University of Cologne, Germany. Furthermore, both isotopes are populated in an elusive reaction channel in the 11B+130Te fusion-evaporation reaction utilizing the HORUS -ray array. The level scheme above the J� = 10+ isomer in 136Ba is revised and extended up to an excitation energy of approx. 5.5 MeV. From the results of angular-correlation measurements, the Ex = 3707- and Ex = 4920-keV states are identified as the bandheads of positive- and negative-parity cascades. While the high-spin regimes of both 132Te and 134Xe are characterized by high-energy 12+ ! 10+ transitions, the 136Ba E2 ground-state band is interrupted by negativeparity states only a few hundred keV above the J� = 10+ isomer. Furthermore, spins are established for several hitherto unassigned high-spin states in 137Ba. The new results close a gap along the highspin structure of N < 82 Ba isotopes. Experimental results are compared to large-scale shell-model calculations employing the GCN50:82, Realistic SM, PQM130 and SN100PN interactions. The calculations suggest that the bandheads of the positive-parity bands in both isotopes are predominantly of proton character.

Published
2019

28. Lifetime measurements in Ti 52 , 54 to study shell evolution toward N = 32

Author

A. Goldkuhle, C. Fransen, A. Blazhev, M. Beckers, B. Birkenbach, T. Braunroth, E. Clément, A. Dewald, J. Dudouet, J. Eberth, H. Hess, B. Jacquot, J. Jolie, Y.-H. Kim, A. Lemasson, S. M. Lenzi, H. J. Li, J. Litzinger, C. Michelagnoli, C. Müller-Gatermann, B. S. Nara Singh, R. M. Pérez-Vidal, D. Ralet, P. Reiter, A. Vogt, N. Warr, K. O. Zell, A. Ataç, D. Barrientos, C. Barthe-Dejean, G. Benzoni

Published
2019
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29. Millisecond 23/2+ isomers in the N=79 isotones Xe133 and Ba135

Author

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

Subjects
Physics, Millisecond, Spectrometer, 010308 nuclear & particles physics, Nuclear structure, Nuclear shell model, Parity (physics), 01 natural sciences, Nuclear physics, 0103 physical sciences, AGATA, 010306 general physics, Spectroscopy, Excitation
Abstract

Detailed information on isomeric states in A ≈ 135 nuclei is exploited to benchmark shell-model calculations in the region northwest of doubly-magic nucleus 132Sn. The N = 79 isotones 133Xe and 135Ba are studied after multinucleon transfer (MNT) in the 136Xe + 208Pb reaction employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy and in a pulsed-beam experiment at the FN tandem accelerator of the University of Cologne, Germany utilizing a 9Be+130Te fusion-evaporation reaction at a beam energy of 40 MeV. Isomeric states are identified via delayed γ-ray spectroscopy. Hitherto tentative excitation energy, spin, and parity assignments of the 2107-keV Jπ = 23/2+ isomer in 133Xe are confirmed and a half-life of T1/2 = 8.64(13) ms is measured. The 2388-keV state in 135Ba is identified as a Jπ = 23/2+ isomer with a half-life of 1.06(4) ms. The new results show a smooth onset of isomeric Jπ = 23/2+ states along the N = 79 isotones and close a gap in the high-spin systematics towards the recently investigated Jπ = 23/2+ isomer in 139Nd. The resulting systematics of M2 reduced transition probabilities is discussed within the framework of the nuclear shell model. Latest large-scale shell-model calculations employing the SN100PN, GCN50:82, SN100-KTH, and a realistic effective interaction reproduce the experimental findings generally well and give insight into the structure of the isomers.

Published
2018

30. Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the Ni78 Region: A Hint from Lifetime Measurements

Author

C. Delafosse, D. Verney, P. Marević, A. Gottardo, C. Michelagnoli, A. Lemasson, A. Goasduff, J. Ljungvall, E. Clément, A. Korichi, G. De Angelis, C. Andreoiu, M. Babo, A. Boso, F. Didierjean, J. Dudouet, S. Franchoo, A. Gadea, G. Georgiev, F. Ibrahim, B. Jacquot, T. Konstantinopoulos, S. M. Lenzi, G. Maquart, I. Matea, D. Mengoni, D. R. Napoli, T. Nikšić, L. Olivier, R. M. Pérez-Vidal, C. Portail, F. Recchia, N. Redon, M. Siciliano, I. Stefan, O. Stezowski, D. Vretenar, M. Zielinska, D. Barrientos, G. Benzoni, B. Birkenbach, A. J. Boston, H. C. Boston, B. Cederwall, L. Charles, M. Ciemala, J. Collado, D. M. Cullen, P. Désesquelles, G. de France, C. Domingo-Pardo, J. Eberth, V. González, L. J. Harkness-Brennan, H. Hess, D. S. Judson, A. Jungclaus, W. Korten, A. Lefevre, F. Legruel, R. Menegazzo, B. Million, J. Nyberg, B. Quintana, D. Ralet, P. Reiter, F. Saillant, E. Sanchis, Ch. Theisen, and J. J. Valiente Dobon

Subjects
Physics, Valence (chemistry), Proton, 010308 nuclear & particles physics, General Physics and Astronomy, 01 natural sciences, Particle identification, Recoil, Excited state, 0103 physical sciences, Quadrupole, Neutron, AGATA, Atomic physics, 010306 general physics
Abstract

Lifetime measurements of excited states of the light N = 52 isotones 88 Kr , 86 Se , and 84 Ge have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B ( E 2 ; 2 + → 0 + ) and B ( E 2 ; 4 + → 2 + ) were obtained for the first time for the hard-to-reach 84 Ge . While the B ( E 2 ; 2 + → 0 + ) values of 88 Kr , 86 Se saturate the maximum quadrupole collectivity offered by the natural valence ( 3 s , 2 d , 1 g 7 / 2 , 1 h 11 / 2 ) space of an inert 78 Ni core, the value obtained for 84 Ge largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N ≲ 49 , extend beyond N = 50 . The onset of collectivity at Z = 32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector ρ field in shell-structure evolution.

Published
2018

31. 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

32. Transition probabilities in neutron-rich Se80,82 and the role of the νg9/2 orbital

Author

R. Menegazzo, P. Reiter, R. Lozeva, Suzana Szilner, G. de Angelis, F. Didierjean, A. Blazhev, Begoña Quintana, O. Stézowski, Bo Cederwall, J. Litzinger, C. Fransen, O. Möller, E. Farnea, F. Ibrahim, Ch. Theisen, J. Grebosz, D. Mengoni, Norbert Pietralla, J. Jolie, M. Hackstein, A. M. Stefanini, V. Vandone, D. Verney, P. Désesquelles, P. A. Söderström, E. Sahin, Hans-Jurgen E. Hess, L. Corradi, A. Dewald, B. Million, G. Montagnoli, Roman Gernhäuser, E. Ellinger, A. Gottardo, F. Recchia, J. J. Valiente-Dobón, F. C. L. Crespi, D. Bazzacco, B. Birkenbach, A. Jungclaus, T. Mijatović, V. Modamio, E. Fioretto, Megumi Niikura, M. D. Salsac, Thomas Braunroth, A. Maj, A. Vogt, A. Pullia, F. Scarlassara, Alain Goasduff, S. Leoni, W. Korten, G. Pollarolo, A. Bracco, S. Lunardi, D. Montanari, A. I. Morales, D. R. Napoli, S. Bottoni, J. Eberth, K. Kolos, G. Duchêne, Denise De Rosso, C. Michelagnoli, and Andreas Görgen

Subjects
Physics, 010308 nuclear & particles physics, Yrast, Nuclear structure, Deep inelastic scattering, 01 natural sciences, Particle identification, Nuclear physics, Excited state, 0103 physical sciences, Neutron, AGATA, 010306 general physics, Spin (physics)
Abstract

Transition probabilities of intermediate-spin yrast and non-yrast excitations in 80, 82Se were investigated in a recoil distance Doppler-shift (RDDS) experiment performed at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro. The Cologne Plunger device for deep inelastic scattering was used for the RDDS technique and was combined with the AGATA Demonstrator array for the γ-ray detection and coupled to the PRISMA magnetic spectrometer for an event-by-event particle identification. In 80Se, the level lifetimes of the yrast (6+1) and (8+1) states and of a non-yrast band feeding the yrast 4+1 state are determined. A spin and parity assignment of the head of this sideband is discussed based on the experimental results and supported by large-scale shell-model calculations. In 82Se, the level lifetimes of the yrast 6+1 state and the yrare 4+2 state and lifetime limits of the yrast (10+1) state and of the 5−1 state are determined. Although the experimental results contain large uncertainties, they are interpreted with care in terms of large-scale shell-model calculations using the effective interactions JUN45 and jj44b. The excited states' wave functions are investigated and discussed with respect to the role of the neutron g9/2 orbital.

Published
2018

33. Quadrupole collectivity in Ca42 from low-energy Coulomb excitation with AGATA

Author

D. Mengoni, M. Kisieliński, G. Anil Kumar, M. Kicińska-Habior, D. Karpiński, G. Lehaut, S. F. Özmen, A. Colombo, F. Recchia, R. Menegazzo, J. Iwanicki, F. Azaiez, B. Million, J. Eberth, D. M. Cullen, N. Toniolo, G. Maron, G. de Angelis, M. Krzysiek, O. Stezowski, P. Reiter, B. Birkenbach, D. T. Doherty, M. D. Salsac, P. J. Coleman-Smith, M. Kowalczyk, M. Gulmini, B. Bounthong, J. Srebrny, S. Franchoo, Hans-Jurgen E. Hess, K. Rusek, M. Ciemala, A. Obertelli, J. L. Wood, S. Leoni, H. Naïdja, C. Michelagnoli, A. Giaz, D. Bazzacco, G. Benzoni, J. Styczen, A. Gottardo, L. Berti, R. Wadsworth, E. Farnea, W. Korten, M. Komorowska, F. C. L. Crespi, Ch. Theisen, M. Kmiecik, A. Jungclaus, Megumi Niikura, D. S. Judson, K. Mazurek, S. Brambilla, B. Dulny, T. Abraham, Joël Chavas, Roberto Isocrate, F. Camera, Tomás R. Rodríguez, P. Bednarczyk, I. Stefan, A. Czermak, L. Charles, G. Jaworski, P. Désesquelles, M. Zieblinski, B. Bruyneel, B. Fornal, X. Grave, S. Lunardi, J. Grebosz, N. Kondratyev, Andreas Görgen, K. Wrzosek-Lipska, G. Rampazzo, Pär-Anders Söderström, Marco Bellato, E. Merchan, Andreas Wiens, Alessandra Corsi, T. Habermann, L. Próchniak, P. J. Napiorkowski, M. Zielińska, A. Lopez-Martens, C. A. Ur, B. Wasilewska, K. Hadynska-Klek, Begoña Quintana, D. Rosso, J. Ljungvall, E. Sahin, A. Gadea, A. Korichi, A. Maj, F. Nowacki, P. Cocconi, Alberto Pullia, Bo Cederwall, N. Karkour, Damiano Bortolato, J. J. Valiente Dobon, D. R. Napoli, W. Meczynski, N. Redon, S. Myalski, and M. Palacz

Subjects
Physics, Sideband, 010308 nuclear & particles physics, Coulomb excitation, 01 natural sciences, Matrix (mathematics), Excited state, 0103 physical sciences, Quadrupole, AGATA, Sum rule in quantum mechanics, Atomic physics, 010306 general physics, Beam (structure)
Abstract

A Coulomb-excitation experiment to study electromagnetic properties of Ca42 was performed using a 170-MeV calcium beam from the TANDEM XPU facility at INFN Laboratori Nazionali di Legnaro. γ rays from excited states in Ca42 were measured with the AGATA spectrometer. The magnitudes and relative signs of ten E2 matrix elements coupling six low-lying states in Ca42, including the diagonal E2 matrix elements of 21+ and 22+ states, were determined using the least-squares code gosia. The obtained set of reduced E2 matrix elements was analyzed using the quadrupole sum rule method and yielded overall quadrupole deformation for 01,2+ and 21,2+ states, as well as triaxiality for 01,2+ states, establishing the coexistence of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in Ca42. The experimental results were compared with the state-of-the-art large-scale shell-model and beyond-mean-field calculations, which reproduce well the general picture of shape coexistence in Ca42.

Published
2018

34. Study of isomeric states in $^{198,200,202,206}$Pb and $^{206}$Hg populated in fragmentation reactions

Author

A. Gottardo, P. Thöle, D. Bazzacco, R. Menegazzo, Dirk Rudolph, Jan Taprogge, E. Wilson, I. Burrows, C. Domingo-Pardo, Pavel Golubev, Claes Fahlander, D. Mengoni, H. J. Wollersheim, A. Pullia, K. Moschner, Herbert Hess, A. Jungclaus, Luis Sarmiento, Vicente González, P. Reiter, J. Eberth, C. Michelagnoli, O. Wieland, Begoña Quintana, F. Ameil, Eric Clément, Th Moeller, Zs. Podolyák, J. Simpson, A. Gadea, Anna Wendt, M. Reese, P. Désesquelles, T. Arici, M. Hackstein, B. Bruyneel, T. Habermann, I. Kojouharov, D. Ralet, E. Gregor, Zena Patel, C. Lizarazo, C. Louchart, Pushpendra Singh, A. Givechev, R. Stegmann, M. L. Cortés, O. Stezowski, J. J. Valiente Dobon, N. Kurz, M. Górska, C. Bauer, N. Lalović, T. Alexander, E. Merchan, Enrique Sanchis, N. Goel, Edward Simpson, J. Gerl, Jnaneswari Gellanki, Norbert Pietralla, M. Bowry, C. Stahl, M. Lettmann, D. R. Napoli, R. Kumar, G. Rainovski, G. Guastalla, J. Jolie, S. Pietri, B. Birkenbach, M. D. Salsac, M. A. Bentley, D. S. Judson, H. Schaffner, P. Boutachkov, P. H. Regan, R. Wood, 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, Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), AGATA, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and 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)

Subjects
Nuclear and High Energy Physics, isomeric decays, Astrophysics::High Energy Astrophysical Phenomena, Population, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Fragmentation (mass spectrometry), Subatomic Physics, 0103 physical sciences, Gamma spectroscopy, Gamma-ray spectroscopy, 010306 general physics, education, Nuclear Experiment, Physics, education.field_of_study, Isotope, 010308 nuclear & particles physics, Nuclear shell model, direct reactions, relativistic projectile fragmentation, electromagnetic transitions, nuclear shell model, AGATA, PreSPEC-AGATA, Atomic physics, Beam (structure)
Abstract

International audience; Isomeric states in isotopes in the vicinity of doubly-magic 208Pb were populatedfollowing reactions of a relativistic 208Pb primary beam impinging on a9Be fragmentation target. Secondary beams of 198,200,202,206Pb and 206Hg wereisotopically separated and implanted in a passive stopper positioned in thefocal plane of the GSI Fragment Separator. Delayed γ rays were detected withthe Advanced Gamma Tracking Array (AGATA). Decay schemes were reevaluatedand interpreted with shell-model calculations. The momentumdependentpopulation of isomeric states in the two-nucleon hole nuclei206Pb/206Hg was found to differ from the population of multi neutron-holeisomeric states in 198,200,202Pb.

Published
2018

35. 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

36. Pygmy dipole resonance in 124Sn populated by inelastic scattering of 17O

Author

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

Subjects
Elastic scattering, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Isoscalar, Gamma ray, Inelastic scattering, 01 natural sciences, 7. Clean energy, Resonance (particle physics), lcsh:QC1-999, Isospin character, Low-lying electric dipole excitations, Ion, Nuclear physics, Dipole, Low-lying electric dipole excitations 124Sn, 0103 physical sciences, AGATA, Atomic physics, 010306 general physics, 124Sn, lcsh:Physics
Abstract

L. Pellegri et al. ; 5 pags. ; 6 figs. ; open access article under the CC BY license. Funded by SCOAP3, © 2014 The Authors. The γ decay from the high-lying states of 124Sn was measured using the inelastic scattering of 17O at 340 MeV. The emitted γ rays were detected with high resolution with the AGATA demonstrator array and the scattered ions were detected in two segmented δE-E silicon telescopes. The angular distribution was measured both for the γ rays and the scattered 17O ions. An accumulation of E1 strength below the particle threshold was found and compared with previous data obtained with (γ, γ') and (α, α'γ) reactions. The present results of elastic scattering, and excitation of E2 and E1 states were analysed using the DWBA approach. From this comprehensive description the isoscalar component of the 1- excited states was extracted. The obtained values are based on the comparison of the data with DWBA calculations including a form factor deduced using a microscopic transition density., Grant No. 2011/03/B/ST2/01894; (iii) the National Superconducting Cyclotron Laboratory at MSU; (iv) the US NSF Grant PHY-1204486; and the German BMBF under Grant 06KY9136.

Published
2014
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37. 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

38. In-beam γ -ray spectroscopy of the neutron-rich platinum isotope Pt200 toward the N=126 shell gap

Author

S. M. Lenzi, M. Bunce, A. Vogt, B. Birkenbach, A. M. Bizzeti-Sona, A. Gottardo, W. Korten, Michele Sferrazza, P. Reiter, A. Kusoglu, M. D. Salsac, J. Walshe, C. A. Ur, P. R. John, Fernando Scarlassara, F. Recchia, P. G. Bizzeti, D. Bazzacco, A. M. Stefanini, L. Corradi, A. Bracco, L. Grente, C. Wheldon, Roberto Menegazzo, G. Montagnoli, G. Pollarolo, D. Mengoni, Tz. Kokalova, T. Mijatović, V. Modamio, Tomás R. Rodríguez, Zs. Podolyák, A. Gadea, Herbert Hess, F. Browne, M. Barr, G. Benzoni, F. C. L. Crespi, Suzana Szilner, E. Fioretto, B. Melon, S. Leoni, M. Bowry, E. Farnea, C. Michelagnoli, S. Bottoni, S. Lunardi, D. Montanari, G. de Angelis, Oliver J. Roberts, Pär-Anders Söderström, E. Sahin, J. Ljungvall, J. J. Valiente-Dobón, N. I. Ashwood, D. R. Napoli, F. Camera, and T. Alexander

Subjects
Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Gamma ray, Order (ring theory), 7. Clean energy, 01 natural sciences, medicine.anatomical_structure, Excited state, 0103 physical sciences, medicine, Neutron, AGATA, Gamma spectroscopy, Atomic physics, Nuclear Experiment, 010306 general physics, Spectroscopy, Nucleus
Abstract

The neutron-rich nucleus \nucleus{200}{Pt} is investigated via in-beam \gamma-ray spectroscopy in order to study the shape evolution in the neutron-rich platinum isotopes towards the N = 126 shell closure. The two-neutron transfer reaction \nucleus{198}{Pt}(\nucleus{82}{Se}, \nucleus{80}{Se})\nucleus{200}{Pt} is used to populate excited states of \nucleus{200}{Pt}. The Advanced Gamma Ray Tracking Array (AGATA) demonstrator coupled with the PRISMA spectrometer detects \gamma rays coincident with the \nucleus{80}{Se} recoils, the binary partner of \nucleus{200}{Pt}. The binary partner method is applied to extract the \gamma-ray transitions and build the level scheme of \nucleus{200}{Pt}. The level at 1884\,keV reported by Yates et. al [Phys. Rev. C 37, 1889] was confirmed to be at 1882.1\,keV and assigned as the (6^+_1) state. An additional \gamma ray was found and it presumably de-excites the (8^+_1) state. The results are compared with state-of-the-art beyond mean-field calculations, performed for the even-even \nucleus{190-204}{Pt} isotopes, revealing that \nucleus{200}{Pt} marks the transition from the \gamma-unstable behaviour of lighter Pt nuclei towards a more spherical one when approaching the N=126 shell closure.

Published
2017

39. Conceptual design of the AGATA 1$\pi$ array at GANIL

Author

E. Clément, C. Michelagnoli, G. de France, H.J. Li, A. Lemasson, C. Barthe Dejean, M. Beuzard, P. Bougault, J. Cacitti, J.-L. Foucher, G. Fremont, P. Gangnant, J. Goupil, C. Houarner, M. Jean, A. Lefevre, L. Legeard, F. Legruel, C. Maugeais, L. Ménager, N. Ménard, H. Munoz, M. Ozille, B. Raine, J.A. Ropert, F. Saillant, C. Spitaels, M. Tripon, Ph. Vallerand, G. Voltolini, W. Korten, M.-D. Salsac, Ch. Theisen, M. Zielińska, T. Joannem, M. Karolak, M. Kebbiri, A. Lotode, R. Touzery, Ch. Walter, A. Korichi, J. Ljungvall, A. Lopez-Martens, D. Ralet, N. Dosme, X. Grave, N. Karkour, X. Lafay, E. Legay, I. Kojouharov, C. Domingo-Pardo, A. Gadea, R.M. Pérez-Vidal, J.V. Civera, B. Birkenbach, J. Eberth, H. Hess, L. Lewandowski, P. Reiter, A. Nannini, G. De Angelis, G. Jaworski, P. John, D.R. Napoli, J.J. Valiente-Dobón, D. Barrientos, D. Bortolato, G. Benzoni, A. Bracco, S. Brambilla, F. Camera, F.C.L. Crespi, S. Leoni, B. Million, A. Pullia, O. Wieland, D. Bazzacco, S.M. Lenzi, S. Lunardi, R. Menegazzo, D. Mengoni, F. Recchia, M. Bellato, R. Isocrate, F.J. Egea Canet, F. Didierjean, G. Duchêne, R. Baumann, M. Brucker, E. Dangelser, M. Filliger, H. Friedmann, G. Gaudiot, J.-N. Grapton, H. Kocher, C. Mathieu, M.-H. Sigward, D. Thomas, S. Veeramootoo, J. Dudouet, O. Stézowski, C. Aufranc, Y. Aubert, M. Labiche, J. Simpson, I. Burrows, P.J. Coleman-Smith, A. Grant, I.H. Lazarus, P.S. Morrall, V.F.E. Pucknell, A. Boston, D.S. Judson, N. Lalović, J. Nyberg, J. Collado, V. González, I. Kuti, B.M. Nyakó, A. Maj, M. Rudigier, 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), 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, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, AGATA, 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), 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), Instituto de Fisica Corpuscular (IFIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universitat de València (UV), University of Cologne, Istituto Nazionale di Fisica Nucleare, Sezione di Firenze (INFN, Sezione di Firenze), Istituto Nazionale di Fisica Nucleare (INFN), INFN Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Sezione di Milano (INFN), Istituto Nazionale di Fisica Nucleare, Sezione di Padova (INFN, Sezione di Padova), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Computational Science and Engineering Department [Daresbury] (STFC), Science & Technologie Facilities Council, University of Liverpool, Lund University [Lund], Uppsala University, Department of Electronic Engineering [Universitat Politecnica de Valencia], Universitat Politècnica de València (UPV), Hungarian Academy of Sciences (MTA), Institute of Physics, Polish Academy of Sciences, Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics, University of Surrey, University of Surrey (UNIS), the EU FEDER funds, MINECO and Generalitat Valenciana, Spain, under the Grants FPA2014-57196-C5, PROMETEOII/2014/019, European Project: 262010,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2010-1,ENSAR(2010), and European Project: 654002,H2020,H2020-INFRAIA-2014-2015,ENSAR2(2016)

Subjects
Nuclear and High Energy Physics, Plunger device, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Cyclotron, Scintillator, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Accelerator Physics and Instrumentation, Tracking (particle physics), 01 natural sciences, 7. Clean energy, law.invention, Nuclear physics, Conceptual design, law, 0103 physical sciences, PARIS LaBr3 detector, Neutron detection, Pulse shape analysis, AGATA spectrometer, 010306 general physics, Nuclear Experiment, Instrumentation, Physics, Spectrometer, VAMOS plus plus spectrometer, 010308 nuclear & particles physics, Detector, FATIMA LaBr3 detector, Acceleratorfysik och instrumentering, DIAMANT detector, NEDA detector, Author Keywords:AGATA spectrometer, Physics::Accelerator Physics, AGATA, gamma-ray tracking, GANIL facility
Abstract

The Advanced GAmma Tracking Array (AGATA) has been installed at the GANIL facility, Caen-France. This setup exploits the stable and radioactive heavy-ions beams delivered by the cyclotron accelerator complex of GANIL. Additionally, it benefits from a large palette of ancillary detectors and spectrometers to address in-beam γ-ray spectroscopy of exotic nuclei. The set-up has been designed to couple AGATA with a magnetic spectrometer, charged-particle and neutron detectors, scintillators for the detection of high-energy γ rays and other devices such as a plunger to measure nuclear lifetimes. In this paper, the design and the mechanical characteristics of the set-up are described. Based on simulations, expected performances of the AGATA l π array are presented. Title in WoS: Conceptual design of the AGATA 1 pi array at GANIL

Published
2017

40. Kr369660 –Low- Z Boundary of the Island of Deformation at N=60

Author

J. Dudouet, A. Lemasson, G. Duchêne, M. Rejmund, E. Clément, C. Michelagnoli, F. Didierjean, A. Korichi, G. Maquart, O. Stezowski, C. Lizarazo, R. M. Pérez-Vidal, C. Andreoiu, G. de Angelis, A. Astier, C. Delafosse, I. Deloncle, Z. Dombradi, G. de France, A. Gadea, A. Gottardo, B. Jacquot, P. Jones, T. Konstantinopoulos, I. Kuti, F. Le Blanc, S. M. Lenzi, G. Li, R. Lozeva, B. Million, D. R. Napoli, A. Navin, C. M. Petrache, N. Pietralla, D. Ralet, M. Ramdhane, N. Redon, C. Schmitt, D. Sohler, D. Verney, D. Barrientos, B. Birkenbach, I. Burrows, L. Charles, J. Collado, D. M. Cullen, P. Désesquelles, C. Domingo Pardo, V. González, L. Harkness-Brennan, H. Hess, D. S. Judson, M. Karolak, W. Korten, M. Labiche, J. Ljungvall, R. Menegazzo, D. Mengoni, A. Pullia, F. Recchia, P. Reiter, M. D. Salsac, E. Sanchis, Ch. Theisen, J. J. Valiente-Dobón, and M. Zielińska

Subjects
Physics, Proton, 010308 nuclear & particles physics, Fission, General Physics and Astronomy, 01 natural sciences, Atomic orbital, Excited state, Neutron number, 0103 physical sciences, Quadrupole, Atomic number, Atomic physics, Nuclear Experiment, 010306 general physics, Spectroscopy
Abstract

Prompt γ-ray spectroscopy of the neutron-rich $^{96}$Kr, produced in transfer- and fusion-induced fission reactions, has been performed using the combination of the Advanced Gamma Tracking Array and the VAMOS++ spectrometer. A second excited state, assigned to $J^π$ = $4^+$, is observed for the first time, and a previously reported level energy of the first 2+ excited state is confirmed. The measured energy ratio R4/2 = E($4^+$)/E($2^+$) = 2.12(1) indicates that this nucleus does not show a well-developed collectivity contrary to that seen in heavier N = 60 isotones. This new measurement highlights an abrupt transition of the degree of collectivity as a function of the proton number at Z = 36, of similar amplitude to that observed at N = 60 at higher Z values. A possible reason for this abrupt transition could be related to the insufficient proton excitations in the g9/2, d5/2, and s1/2 orbitals to generate strong quadrupole correlations or to the coexistence of competing different shapes. An unexpected continuous decrease of R4/2 as a function of the neutron number up to N = 60 is also evidenced. This measurement establishes the Kr isotopic chain as the low-Z boundary of the island of deformation for N = 60 isotones. A comparison with available theoretical predictions using different beyond mean-field approaches shows that these models fail to reproduce the abrupt transitions at N = 60 and Z = 36.

Published
2017

41. 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

42. Measurement of lifetimes in Fe62,64,Co61,63 , and Mn59

Author

M. Klintefjord, J. Ljungvall, A. Görgen, S. M. Lenzi, F. L. Bello Garrote, A. Blazhev, E. Clément, G. de France, J.-P. Delaroche, P. Désesquelles, A. Dewald, D. T. Doherty, C. Fransen, A. Gengelbach, G. Georgiev, M. Girod, A. Goasduff, A. Gottardo, K. Hadyńska-Klȩk, B. Jacquot, T. Konstantinopoulos, A. Korichi, A. Lemasson, J. Libert, A. Lopez-Martens, C. Michelagnoli, A. Navin, J. Nyberg, R. M. Pérez-Vidal, S. Roccia, E. Sahin, I. Stefan, A. E. Stuchbery, M. Zielińska, D. Barrientos, B. Birkenbach, A. Boston, L. Charles, M. Ciemala, J. Dudouet, J. Eberth, A. Gadea, V. González, L. Harkness-Brennan, H. Hess, A. Jungclaus, W. Korten, R. Menegazzo, D. Mengoni, B. Million, A. Pullia, D. Ralet, F. Recchia, P. Reiter, M. D. Salsac, E. Sanchis, O. Stezowski, Ch. Theisen, and J. J. Valiente Dobon

Subjects
Physics, 010308 nuclear & particles physics, 0103 physical sciences, Creative commons, 010306 general physics, 01 natural sciences, Engineering physics
Abstract

M. Klintefjord et al. -- 11 pags., 8 figs., 1 tab. -- Open Access funded by Creative Commons Atribution Licence 4.0

Published
2017

43. Compton imaging with a highly-segmented, position-sensitive HPGe detector

Author

M. Winkel, Herbert Hess, M. Schlarb, B. Weiler, P. Reiter, L. Maier, Roman Gernhäuser, L. Lewandowski, B. Bruyneel, B. Birkenbach, J. Eberth, T. Steinbach, and R. Hirsch

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, business.industry, Scattering, Detector, Solid angle, Compton scattering, Radiation, 01 natural sciences, Coincidence, Particle detector, Semiconductor detector, Optics, 0103 physical sciences, 010306 general physics, business
Abstract

A Compton camera based on a highly-segmented high-purity germanium (HPGe) detector and a double-sided silicon-strip detector (DSSD) was developed, tested, and put into operation; the origin of \(\gamma\) radiation was determined successfully. The Compton camera is operated in two different modes. Coincidences from Compton-scattered \(\gamma\)-ray events between DSSD and HPGe detector allow for best angular resolution; while the high-efficiency mode takes advantage of the position sensitivity of the highly-segmented HPGe detector. In this mode the setup is sensitive to the whole \( 4\pi\) solid angle. The interaction-point positions in the 36-fold segmented large-volume HPGe detector are determined by pulse-shape analysis (PSA) of all HPGe detector signals. Imaging algorithms were developed for each mode and successfully implemented. The angular resolution sensitively depends on parameters such as geometry, selected multiplicity and interaction-point distances. Best results were obtained taking into account the crosstalk properties, the time alignment of the signals and the distance metric for the PSA for both operation modes. An angular resolution between \( 13.8^{\circ}\) and \( 19.1^{\circ}\), depending on the minimal interaction-point distance for the high-efficiency mode at an energy of 1275 keV, was achieved. In the coincidence mode, an increased angular resolution of \( 4.6^{\circ}\) was determined for the same \(\gamma\)-ray energy.

Published
2017

44. $_{36}^{96}$Kr$_{60}$–low-$Z$ boundary of the island of deformation at $N=60$

Author

J, Dudouet, A, Lemasson, G, Duchêne, M, Rejmund, E, Clément, C, Michelagnoli, F, Didierjean, A, Korichi, G, Maquart, O, Stezowski, C, Lizarazo, R M, Pérez-Vidal, C, Andreoiu, G, de Angelis, A, Astier, C, Delafosse, I, Deloncle, Z, Dombradi, G, de France, A, Gadea, A, Gottardo, B, Jacquot, P, Jones, T, Konstantinopoulos, I, Kuti, F, Le Blanc, S M, Lenzi, G, Li, R, Lozeva, B, Million, D R, Napoli, A, Navin, C M, Petrache, N, Pietralla, D, Ralet, M, Ramdhane, N, Redon, C, Schmitt, D, Sohler, D, Verney, D, Barrientos, B, Birkenbach, I, Burrows, L, Charles, J, Collado, D M, Cullen, P, Désesquelles, C, Domingo Pardo, V, González, L, Harkness-Brennan, H, Hess, D S, Judson, M, Karolak, W, Korten, M, Labiche, J, Ljungvall, R, Menegazzo, D, Mengoni, A, Pullia, F, Recchia, P, Reiter, M D, Salsac, E, Sanchis, Ch, Theisen, J J, Valiente-Dobón, and M, Zielińska

Subjects
Nuclear Physics - Experiment
Abstract

Prompt γ-ray spectroscopy of the neutron-rich ^{96}Kr, produced in transfer- and fusion-induced fission reactions, has been performed using the combination of the Advanced Gamma Tracking Array and the VAMOS++ spectrometer. A second excited state, assigned to J^{π}=4^{+}, is observed for the first time, and a previously reported level energy of the first 2^{+} excited state is confirmed. The measured energy ratio R_{4/2}=E(4^{+})/E(2^{+})=2.12(1) indicates that this nucleus does not show a well-developed collectivity contrary to that seen in heavier N=60 isotones. This new measurement highlights an abrupt transition of the degree of collectivity as a function of the proton number at Z=36, of similar amplitude to that observed at N=60 at higher Z values. A possible reason for this abrupt transition could be related to the insufficient proton excitations in the g_{9/2}, d_{5/2}, and s_{1/2} orbitals to generate strong quadrupole correlations or to the coexistence of competing different shapes. An unexpected continuous decrease of R_{4/2} as a function of the neutron number up to N=60 is also evidenced. This measurement establishes the Kr isotopic chain as the low-Z boundary of the island of deformation for N=60 isotones. A comparison with available theoretical predictions using different beyond mean-field approaches shows that these models fail to reproduce the abrupt transitions at N=60 and Z=36.

Published
2017

45. Lifetime measurement of neutron-rich even-even molybdenum isotopes

Author

Torbjörn Bäck, M. Labiche, M. Zielińska, M. Reese, A. Gadea, B. Million, T. Hüyük, F. Camera, R. Knoebel, T. Alexander, E. Gregor, N. Alkhomashi, Maria Doncel, A. Prochazka, A. Atac, D. Mengoni, L. J. Harkness-Brennan, Pushpendra Singh, A. Givechev, A. Gottardo, H. J. Wollersheim, T. Arici, Tomás R. Rodríguez, Alberto Pullia, D. Curien, E. Merchan, L. Sengele, C. Domingo-Pardo, Helmut Weick, A. Jungclaus, Herbert Hess, M. Dewald, P. Thoele, I. Kojouharov, G. Duchêne, S. Pietri, G. de Angelis, F. Didierjean, O. Stezowski, J. S. Winfield, N. Kurz, M. Hackstein, N. Goel, B. Birkenbach, P. Reiter, D. S. Judson, C. Stahl, E. Clément, F. Ameil, Pavel Golubev, P. Boutachkov, M. Górska, B. Bruyneel, A. Korichi, H. Schaffner, C. Scheidenberger, R. Avigo, F. Recchia, T. Goigoux, D. Bazzacco, Bo Cederwall, Vicente González, M. D. Salsac, P. Désesquelles, A. I. Morales, Zs. Podolyák, J. Gerl, J. J. Valiente Dobon, T. Habermann, Dirk Rudolph, Alison Bruce, D. Ralet, Luis Sarmiento, J. Jolie, D. R. Napoli, C. Louchart-Henning, Johan Nyberg, G. Guastalla, B. S. Nara Singh, Enrique Sanchis, M. Alaqeel, Oliver Wieland, G. Rainovski, J. Eberth, Norbert Pietralla, Hans Geissel, F. Ghazi Moradi, Anna Wendt, M. L. Cortés, S. Ceruti, N. Lalović, G. Henning, Begoña Quintana, F. Naqvi, W. Korten, 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), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Generalitat Valenciana, Ministerio de Economía y Competitividad (España), Science and Technology Facilities Council (UK), Federal Ministry of Education and Research (Germany), Swedish Research Council, European Commission, Helmholtz International Center for FAIR, 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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, Subatomic Physics, 0103 physical sciences, Neutron, ddc:530, 010306 general physics, Mass number, Physics, Isotope, 010308 nuclear & particles physics, relativistic projectile fragmentation, 3. Good health, secondary fragmentation, gamma-ray spectroscopy, chemistry, Molybdenum, Excited state, Quadrupole, Física nuclear, AGATA, Atomic physics, Energy (signal processing)
Abstract

D. Ralet et al. -- 11 pags., 10 figs., 3 tabs., Background: In the neutron-rich A≈100 mass region, rapid shape changes as a function of nucleon number as well as coexistence of prolate, oblate, and triaxial shapes are predicted by various theoretical models. Lifetime measurements of excited levels in the molybdenum isotopes allow the determination of transitional quadrupole moments, which in turn provides structural information regarding the predicted shape change. Purpose: The present paper reports on the experimental setup, the method that allowed one to measure the lifetimes of excited states in even-even molybdenum isotopes from mass A=100 up to mass A=108, and the results that were obtained. Method: The isotopes of interest were populated by secondary knock-out reaction of neutron-rich nuclei separated and identified by the GSI fragment separator at relativistic beam energies and detected by the sensitive PreSPEC-AGATA experimental setup. The latter included the Lund-York-Cologne calorimeter for identification, tracking, and velocity measurement of ejectiles, and AGATA, an array of position sensitive segmented HPGe detectors, used to determine the interaction positions of the γ ray enabling a precise Doppler correction. The lifetimes were determined with a relativistic version of the Doppler-shift-attenuation method using the systematic shift of the energy after Doppler correction of a γ-ray transition with a known energy. This relativistic Doppler-shift-attenuation method allowed the determination of mean lifetimes from 2 to 250 ps. Results: Even-even molybdenum isotopes from mass A=100 to A=108 were studied. The decays of the low-lying states in the ground-state band were observed. In particular, two mean lifetimes were measured for the first time: τ=29.7-9.1+11.3 ps for the 4+ state of Mo108 and τ=3.2-0.7+0.7 ps for the 6+ state of Mo102. Conclusions: The reduced transition strengths B(E2), calculated from lifetimes measured in this experiment, compared to beyond-mean-field calculations, indicate a gradual shape transition in the chain of molybdenum isotopes when going from A=100 to A=108 with a maximum reached at N=64. The transition probabilities decrease for Mo108 which may be related to its well-pronounced triaxial shape indicated by the calculations., This work was supported by the BMBF under Grants No. 05P09RDFN4, No. 05P12RDFN8, and No. 05P12PKFNE and by the LOEWE center HIC for FAIR. Part of this work was supported by the P2IO excellence center. This work was also supported by the European Community FP7–Capacities, ENSAR Contract No. 262010, by the Swedish Research Council under Contracts No. 2010-147, No. 2010-3694, No. 2011-5253, No. 2011-6127, and No. 2014-5558, by the IN2P3- GSI No. 02-42 collaboration, by the Science and Technology Facilities Council (STFC) and by MINECO, Spain, under Grant No. FPA2014-57196-C5, and Generalitat Valenciana, Spain, under Grant No. PROMETEOII/2014/019

Published
2017

46. 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

47. Spectroscopy of Actinide Nuclei – Perspectives with Position Sensitive HPGe Detectors

Author

P. Reiter, T. Kotthaus, and B. Birkenbach

Subjects
Physics, Spectrometer, Detector, Nuclear Theory, Physics and Astronomy(all), Tracking (particle physics), transfer reaction, Particle detector, Nuclear physics, In-beam gamma-ray spectroscopy, Coincident, Neutron, AGATA, Spectroscopy, Nuclear Experiment, multi-nucleon transfer reaction, actinide nuclei
Abstract

Recent advances in in-beam gamma-ray spectroscopy of actinide nuclei are based on highly efficient arrays of escape-suppressed spectrometers. The sensitivity of these detector arrays is greatly enhanced by the combination with powerful mass separators or particle detector systems. This technique is demonstrated by an experiment to investigate excited states in 234 U after the one-neutron-transfer reaction 235 U(d,t). In coincidence with the outgoing tritons, γ-rays were detected with the highly efficient MINIBALL spectrometer. In the near future an even enhanced sensitivity will be achieved by utilizing position sensitive HPGe detectors which will exploit the novel detection method of gamma-ray energy tracking in electrically segmented germanium detectors. An example for this novel approach is the investigation neutron-rich actinide Th and U nuclei after multi nucleon transfer reactions employing the AGATA demonstrator and PRISMA setup at LNL, Italy. A primary 136 Xe beam hitting a 238 U target was used to produce the nuclei of interest. Beam-like reaction products after neutron transfer were selected by the PRISMA spectrometer. Coincident γ-rays from excited states in beam and target like particles were measured with the position sensitive AGATA HPGe detectors. Improved Doppler correction and quality of the γ-spectra is based on the novel γ-ray tracking technique, which was successfully exploited in this region.

Published
2014
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48. Role of the Δ Resonance in the Population of a Four-Nucleon State in the Fe56→Fe54 Reaction at Relativistic Energies

Author

C. Louchart, I. Kojouharov, G. de Angelis, B. Bruyneel, A. Maj, J. Gerl, W. Korten, T. Alexander, D. S. Judson, M. D. Salsac, L. J. Harkness-Brennan, M. Reese, S. Pietri, H. Schaffner, J. J. Valiente Dobon, M. Labiche, Zena Patel, Dirk Rudolph, M. Lettmann, Luis Sarmiento, C. M. Shand, A. Pullia, P. H. Regan, H. Pai, Zs. Dombrádi, J. Eberth, A. Gadea, R. M. Pérez-Vidal, P. Désesquelles, Helmut Weick, B. Birkenbach, A. Jungclaus, D. Mengoni, C. Michelagnoli, Pavel Golubev, E. Wilson, I. Burrows, M. L. Cortés, D. R. Napoli, N. Lalović, D. M. Cullen, L. Charles, Herbert Hess, E. Merchan, Begoña Quintana, Eric Clément, T. Habermann, D. Ralet, T. Arici, G. Rainovski, N. Kurz, M. Górska, Oliver Wieland, Vicente González, P. Boutachkov, Raymond J. Carroll, Zs. Podolyák, P. Reiter, F. Ameil, C. Lizarazo, F. C. L. Crespi, Enrique Sanchis, Norbert Pietralla, Ch Stahl, and D. Mahboub

Subjects
Quark, Physics, education.field_of_study, Proton, 010308 nuclear & particles physics, Nuclear Theory, Population, General Physics and Astronomy, 7. Clean energy, 01 natural sciences, Resonance (particle physics), Momentum, Metastability, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, education, Ground state
Abstract

The 54Fe nucleus was populated from a 56Fe beam impinging on a Be target with an energy of E=A ¼ 500 MeV. The internal decay via γ-ray emission of the 10þ metastable state was observed. As the structure of this isomeric state has to involve at least four unpaired nucleons, it cannot be populated in a simple two-neutron removal reaction from the 56Fe ground state. The isomeric state was produced in the low-momentum (-energy) tail of the parallel momentum (energy) distribution of 54Fe, suggesting that it was populated via the decay of the Δ0 resonance into a proton. This process allows the population of fournucleon states, such as the observed isomer. Therefore, it is concluded that the observation of this 10þ metastable state in 54Fe is a consequence of the quark structure of the nucleons.

Published
2016

49. Role of the Δ Resonance in the Population of a Four-Nucleon State in the $^{56}$Fe → $^{54} $Fe Reaction at Relativistic Energies

Author

Zs, Podolyák, C M, Shand, N, Lalović, J, Gerl, D, Rudolph, T, Alexander, P, Boutachkov, M L, Cortés, M, Górska, I, Kojouharov, N, Kurz, C, Louchart, E, Merchán, C, Michelagnoli, R M, Pérez-Vidal, S, Pietri, D, Ralet, M, Reese, H, Schaffner, Ch, Stahl, H, Weick, F, Ameil, G, de Angelis, T, Arici, R, Carroll, Zs, Dombrádi, A, Gadea, P, Golubev, M, Lettmann, C, Lizarazo, D, Mahboub, H, Pai, Z, Patel, N, Pietralla, P H, Regan, L G, Sarmiento, O, Wieland, E, Wilson, B, Birkenbach, B, Bruyneel, I, Burrows, L, Charles, E, Clément, F C L, Crespi, D M, Cullen, P, Désesquelles, J, Eberth, V, González, T, Habermann, L, Harkness-Brennan, H, Hess, D S, Judson, A, Jungclaus, W, Korten, M, Labiche, A, Maj, D, Mengoni, D R, Napoli, A, Pullia, B, Quintana, G, Rainovski, P, Reiter, M D, Salsac, E, Sanchis, J J, Valiente Dóbon, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), AGATA, 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 de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics and Astronomy (all), gamma-ray spectroscopy, Subatomic Physics, Nuclear Theory, isomer decay, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, relativistic projectile fragmentation
Abstract

The ^{54}Fe nucleus was populated from a ^{56}Fe beam impinging on a Be target with an energy of E/A=500 MeV. The internal decay via γ-ray emission of the 10^{+} metastable state was observed. As the structure of this isomeric state has to involve at least four unpaired nucleons, it cannot be populated in a simple two-neutron removal reaction from the ^{56}Fe ground state. The isomeric state was produced in the low-momentum (-energy) tail of the parallel momentum (energy) distribution of ^{54}Fe, suggesting that it was populated via the decay of the Δ^{0} resonance into a proton. This process allows the population of four-nucleon states, such as the observed isomer. Therefore, it is concluded that the observation of this 10^{+} metastable state in ^{54}Fe is a consequence of the quark structure of the nucleons.

Published
2016

50. 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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