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1. Experimental observation of the M1 scissors mode in 254No

Author

F.L. Bello Garrote, A. Lopez-Martens, A.C. Larsen, I. Deloncle, S. Péru, F. Zeiser, P.T. Greenlees, B.V. Kheswa, K. Auranen, D.L. Bleuel, D.M. Cox, L. Crespo Campo, F. Giacoppo, A. Görgen, T. Grahn, M. Guttormsen, T.W. Hagen, L. Harkness-Brennan, K. Hauschild, G. Henning, R.-D. Herzberg, R. Julin, S. Juutinen, T.A. Laplace, M. Leino, J.E. Midtbø, V. Modamio, J. Pakarinen, P. Papadakis, J. Partanen, T. Renstrøm, K. Rezynkina, M. Sandzelius, J. Sarén, C. Scholey, S. Siem, J. Sorri, S. Stolze, and J. Uusitalo

Subjects
Scissors mode, γ-strength function, Transfermium nuclides, Physics, QC1-999
Abstract

We present the first experimental evidence of the scissors mode in the superheavy nucleus 254No produced in the 208Pb(48Ca, 2nγ))254No reaction. The spectrum of γ rays emitted by the excited 254No nuclei shows an enhanced γ-ray yield for transition energies of ≈2.5 MeV. By measuring the linear polarization properties of the emitted γ rays, we confirm that the transitions in the enhancement region are predominantly of magnetic-dipole character, characteristic for the scissors mode. To further characterize the enhanced γ-ray yield, simulations of the electromagnetic decay of 254No were performed. The observed enhancement is reproduced by including an M1 component in the γ strength function with total strength B(M1↑)=11.8(19)μN2. This is in good agreement with the integrated M1 strength from sum-rule estimates and new calculations within the quasi-particle random-phase approximation presented here. Our results provide a stringent test of phenomenological formulae for the scissors mode currently used in stellar nucleosynthesis calculations. We find that those formulae are not satisfactory, and we recommend using sum-rule estimates assuming a rigid-body moment of inertia instead for describing the scissors mode in superheavy nuclei.

Published
2022
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2. Lifetime measurements of excited states in 169,171,173Os: Persistence of anomalous B(E2) ratios in transitional rare earth nuclei in the presence of a decoupled i13/2 valence neutron

Author

W. Zhang, B. Cederwall, M. Doncel, Ö. Aktas, A. Ertoprak, R. Liotta, C. Qi, T. Grahn, B.S. Nara Singh, D.M. Cullen, D. Hodge, M. Giles, S. Stolze, H. Badran, T. Braunroth, T. Calverley, D.M. Cox, Y.D. Fang, P.T. Greenlees, J. Hilton, E. Ideguchi, R. Julin, S. Juutinen, M. Kumar Raju, H. Li, H. Liu, S. Matta, P. Subramaniam, V. Modamio, J. Pakarinen, P. Papadakis, J. Partanen, C.M. Petrache, P. Rahkila, P. Ruotsalainen, M. Sandzelius, J. Sarén, C. Scholey, J. Sorri, M.J. Taylor, J. Uusitalo, and J.J. Valiente-Dobón

Subjects
Physics, QC1-999
Abstract

Lifetimes of low-lying excited states in the νi13/2+ bands of the neutron-deficient osmium isotopes 169,171,173Os have been measured for the first time using the recoil-distance Doppler shift and recoil-isomer tagging techniques. An unusually low value is observed for the ratio B(E2;21/2+→17/2+)/B(E2;17/2+→13/2+) in 169Os, similar to the “anomalously” low values of the ratio B(E2;41+→21+)/B(E2;21+→0gs+) previously observed in several transitional rare-earth nuclides with even numbers of neutrons and protons, including the neighbouring 168,170Os. Furthermore, the evolution of B(E2;21/2+→17/2+)/B(E2;17/2+→13/2+) with increasing neutron number in the odd-mass isotopic chain 169,171,173Os is observed to follow the same trend as observed previously in the even-even Os isotopes. These findings indicate that the possible quantum phase transition from a seniority conserving structure to a collective regime as a function of neutron number suggested for the even-even systems is maintained in these odd-mass osmium nuclei, with the odd valence neutron merely acting as a “spectator”. As for the even-even nuclei, the phenomenon is highly unexpected for nuclei that are not situated near closed shells.

Published
2021
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3. Strong enhancement of level densities in the crossover from spherical to deformed neodymium isotopes

Author

M. Guttormsen, Y. Alhassid, W. Ryssens, K.O. Ay, M. Ozgur, E. Algin, A.C. Larsen, F.L. Bello Garrote, L. Crespo Campo, T. Dahl-Jacobsen, A. Görgen, T.W. Hagen, V.W. Ingeberg, B.V. Kheswa, M. Klintefjord, J.E. Midtbø, V. Modamio, T. Renstrøm, E. Sahin, S. Siem, G.M. Tveten, and F. Zeiser

Subjects
Nuclear level density, Oslo method, Shell model Monte Carlo, Mean-field theory, Collective enhancement, Physics, QC1-999
Abstract

Understanding the evolution of level densities in the crossover from spherical to well-deformed nuclei has been a long-standing problem in nuclear physics. We measure nuclear level densities for a chain of neodymium isotopes 142,144−151Nd which exhibit such a crossover. These results represent the most complete data set of nuclear level densities to date for an isotopic chain between neutron shell-closure and towards mid-shell. We observe a strong increase of the level densities along the chain with an overall increase by a factor of ≈150 at an excitation energy of 6 MeV and saturation around mass 150. Level densities calculated by the shell model Monte Carlo (SMMC) are in excellent agreement with these experimental results. Based on our experimental and theoretical findings, we offer an explanation of the observed mass dependence of the level densities in terms of the intrinsic single-particle level density and the collective enhancement.

Published
2021
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4. Is seniority a partial dynamic symmetry in the first νg9/2 shell?

Author

A.I. Morales, G. Benzoni, H. Watanabe, G. de Angelis, S. Nishimura, L. Coraggio, A. Gargano, N. Itaco, T. Otsuka, Y. Tsunoda, P. Van Isacker, F. Browne, R. Daido, P. Doornenbal, Y. Fang, G. Lorusso, Z. Patel, S. Rice, L. Sinclair, P.-A. Söderström, T. Sumikama, J.J. Valiente-Dobón, J. Wu, Z.Y. Xu, A. Yagi, R. Yokoyama, H. Baba, R. Avigo, F.L. Bello Garrote, N. Blasi, A. Bracco, A.M. Bruce, F. Camera, S. Ceruti, F.C.L. Crespi, M.-C. Delattre, Zs. Dombradi, A. Gottardo, T. Isobe, I. Kojouharov, N. Kurz, I. Kuti, S. Lalkovski, K. Matsui, B. Melon, D. Mengoni, T. Miyazaki, V. Modamio-Hoybjor, S. Momiyama, D.R. Napoli, M. Niikura, R. Orlandi, Zs. Podolyák, P.H. Regan, H. Sakurai, E. Sahin, D. Sohler, H. Schaffner, R. Taniuchi, J. Taprogge, Zs. Vajta, O. Wieland, and M. Yalcinkaya

Subjects
Physics, QC1-999
Abstract

The low-lying structures of the midshell νg9/2 Ni isotopes 72Ni and 74Ni have been investigated at the RIBF facility in RIKEN within the EURICA collaboration. Previously unobserved low-lying states were accessed for the first time following β decay of the mother nuclei 72Co and 74Co. As a result, we provide a complete picture in terms of the seniority scheme up to the first (8+) levels for both nuclei. The experimental results are compared to shell-model calculations in order to define to what extent the seniority quantum number is preserved in the first neutron g9/2 shell. We find that the disappearance of the seniority isomerism in the (81+) states can be explained by a lowering of the seniority-four (6+) levels as predicted years ago. For 74Ni, the internal de-excitation pattern of the newly observed (62+) state supports a restoration of the normal seniority ordering up to spin J=4. This property, unexplained by the shell-model calculations, is in agreement with a dominance of the single-particle spherical regime near 78Ni.

Published
2018
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5. Type II shell evolution in A=70 isobars from the N≥40 island of inversion

Author

A.I. Morales, G. Benzoni, H. Watanabe, Y. Tsunoda, T. Otsuka, S. Nishimura, F. Browne, R. Daido, P. Doornenbal, Y. Fang, G. Lorusso, Z. Patel, S. Rice, L. Sinclair, P.-A. Söderström, T. Sumikama, J. Wu, Z.Y. Xu, A. Yagi, R. Yokoyama, H. Baba, R. Avigo, F.L. Bello Garrote, N. Blasi, A. Bracco, F. Camera, S. Ceruti, F.C.L. Crespi, G. de Angelis, M.-C. Delattre, Zs. Dombradi, A. Gottardo, T. Isobe, I. Kojouharov, N. Kurz, I. Kuti, K. Matsui, B. Melon, D. Mengoni, T. Miyazaki, V. Modamio-Hoybjor, S. Momiyama, D.R. Napoli, M. Niikura, R. Orlandi, H. Sakurai, E. Sahin, D. Sohler, H. Schaffner, R. Taniuchi, J. Taprogge, Zs. Vajta, J.J. Valiente-Dobón, O. Wieland, and M. Yalcinkaya

Subjects
Physics, QC1-999
Abstract

The level structures of 70Co and 70Ni, populated from the β decay of 70Fe, have been investigated using β-delayed γ-ray spectroscopy following in-flight fission of a 238U beam. The experimental results are compared to Monte-Carlo Shell-Model calculations including the pf+g9/2+d5/2 orbitals. The strong population of a (1+) state at 274 keV in 70Co is at variance with the expected excitation energy of ∼1 MeV from near spherical single-particle estimates. This observation indicates a dominance of prolate-deformed intruder configurations in the low-lying levels, which coexist with the normal near spherical states. It is shown that the β decay of the neutron-rich A=70 isobars from the new island of inversion to the Z=28 closed-shell regime progresses in accordance with a newly reported type of shell evolution, the so-called Type II, which involves many particle-hole excitations across energy gaps.

Published
2017
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6. 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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7. Decay properties of 68,69,70Mn: Probing collectivity up to N=44 in Fe isotopic chain

Author

G. Benzoni, A.I. Morales, H. Watanabe, S. Nishimura, L. Coraggio, N. Itaco, A. Gargano, F. Browne, R. Daido, P. Doornenbal, Y. Fang, G. Lorusso, Z. Patel, S. Rice, L. Sinclair, P.-A. Söderström, T. Sumikama, J. Wu, Z.Y. Xu, R. Yokoyama, H. Baba, R. Avigo, F.L. Bello Garrote, N. Blasi, A. Bracco, F. Camera, S. Ceruti, F.C.L. Crespi, G. de Angelis, M.-C. Delattre, Zs. Dombradi, A. Gottardo, T. Isobe, I. Kuti, K. Matsui, B. Melon, D. Mengoni, T. Miyazaki, V. Modamio-Hoybjor, S. Momiyama, D.R. Napoli, M. Niikura, R. Orlandi, H. Sakurai, E. Sahin, D. Sohler, R. Taniuchi, J. Taprogge, Zs. Vajta, J.J. Valiente-Dobón, O. Wieland, and M. Yalcinkaya

Subjects
Physics, QC1-999
Abstract

The β decays Mn68→Fe68, Mn69→Fe69 and Mn70→Fe70 have been measured at the RIBF facility at RIKEN using the EURICA γ spectrometer combined with an active stopper consisting of a stack of Si detectors. The nuclei were produced as fission fragments from a beam of 238U at a bombarding energy of 345 MeV/nucleon impinging on a Be target and selected using the BigRIPS separator. Half-lives and β-delayed neutron emission probabilities have been extracted for these decays, together with first experimental information on excited states populated in 69,70Fe. The data indicate a continuously increasing deformation for Fe isotopes up to A=70. This is interpreted, as for Cr isotopes, in terms of the interplay between the quadrupole correlations of the ν1d5/2 and ν0g9/2 orbitals and the monopole component of the π0f7/2–ν0f5/2 interaction.

Published
2015
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8. First spectroscopic study of odd-odd Cu78

Author

L. G. Pedersen, E. Sahin, A. Görgen, F. L. Bello Garrote, Y. Tsunoda, T. Otsuka, M. Niikura, S. Nishimura, Z. Xu, H. Baba, G. Benzoni, F. Browne, A. M. Bruce, S. Ceruti, F. C. L. Crespi, R. Daido, G. de Angelis, M.-C. Delattre, Zs. Dombradi, P. Doornenbal, Y. Fang, S. Franchoo, G. Gey, A. Gottardo, T. Isobe, P. R. John, H. S. Jung, I. Kojouharov, T. Kubo, N. Kurz, I. Kuti, Z. Li, G. Lorusso, I. Matea, K. Matsui, D. Mengoni, T. Miyazaki, V. Modamio, S. Momiyama, A. I. Morales, P. Morfouace, D. R. Napoli, F. Naqvi, H. Nishibata, A. Odahara, R. Orlandi, Z. Patel, S. Rice, H. Sakurai, H. Schaffner, L. Sinclair, P.-A. Söderström, D. Sohler, I. G. Stefan, T. Sumikama, D. Suzuki, R. Taniuchi, J. Taprogge, Z. Vajta, J. J. Valiente-Dobón, H. Watanabe, V. Werner, J. Wu, A. Yagi, M. Yalcinkaya, R. Yokoyama, and K. Yoshinaga

Published
2023

9. Observation of a candidate for the M1 scissors resonance in odd-odd Ho166

Author

F. Pogliano, F. L. Bello Garrote, A. C. Larsen, H. C. Berg, D. Gjestvang, A. Görgen, M. Guttormsen, V. W. Ingeberg, T. W. Johansen, K. L. Malatji, E. F. Matthews, M. Markova, J. E. Midtbø, V. Modamio, L. G. Pedersen, E. Sahin, S. Siem, T. G. Tornyi, and A. S. Voyles

Published
2023

10. Decay spectroscopy of Os171,172 and Ir171,172,174

Author

W. Zhang, B. Cederwall, M. Doncel, Ö. Aktas, A. Ertoprak, C. Qi, T. Grahn, B. S. Nara Singh, D. M. Cullen, D. Hodge, M. Giles, S. Stolze, K. Auranen, H. Badran, T. Braunroth, T. Calverley, D. M. Cox, Y. D. Fang, P. T. Greenlees, J. Hilton, E. Ideguchi, R. Julin, S. Juutinen, M. Kumar Raju, M. Leino, H. Li, H. Liu, S. Matta, P. Subramaniam, V. Modamio, J. Pakarinen, P. Papadakis, J. Partanen, C. M. Petrache, P. Rahkila, P. Ruotsalainen, M. Sandzelius, J. Sarén, C. Scholey, J. Sorri, M. J. Taylor, J. Uusitalo, and J. J. Valiente-Dobón

Published
2023

11. Lifetime measurements of states of S35 , S36 , S37 , and S38 using the AGATA γ -ray tracking spectrometer

Author

L. Grocutt, R. Chapman, M. Bouhelal, F. Haas, A. Goasduff, J. F. Smith, R. S. Lubna, S. Courtin, D. Bazzacco, T. Braunroth, L. Capponi, L. Corradi, X. Derkx, P. Desesquelles, M. Doncel, E. Fioretto, A. Gottardo, V. Liberati, B. Melon, D. Mengoni, C. Michelagnoli, T. Mijatović, V. Modamio, G. Montagnoli, D. Montanari, K. F. Mulholland, D. R. Napoli, C. M. Petrache, A. Pipidis, F. Recchia, E. Sahin, P. P. Singh, A. M. Stefanini, S. Szilner, and J. J. Valiente-Dobón

Published
2022

12. Experimental observation of the M1 scissors mode in $^{254}No$

Author

F.L. Bello Garrote, A. Lopez-Martens, A.C. Larsen, I. Deloncle, S. Péru, F. Zeiser, P.T. Greenlees, B.V. Kheswa, K. Auranen, D.L. Bleuel, D.M. Cox, L. Crespo Campo, F. Giacoppo, A. Görgen, T. Grahn, M. Guttormsen, T.W. Hagen, L. Harkness-Brennan, K. Hauschild, G. Henning, R.-D. Herzberg, R. Julin, S. Juutinen, T.A. Laplace, M. Leino, J.E. Midtbø, V. Modamio, J. Pakarinen, P. Papadakis, J. Partanen, T. Renstrøm, K. Rezynkina, M. Sandzelius, J. Sarén, C. Scholey, S. Siem, J. Sorri, S. Stolze, J. Uusitalo, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), CEA DAM ILE-DE-FRANCE - Bruyères-le-Châtel [Arpajon] (CEA DAM IDF), Département Recherches Subatomiques (DRS-IPHC), Institut Pluridisciplinaire Hubert Curien (IPHC), 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)-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
Nuclear and High Energy Physics, scissors mode, transfermium nuclides, γ-strength function, ddc:530, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], ydinfysiikka
Abstract

Physics letters / B 834, 137479 (2022). doi:10.1016/j.physletb.2022.137479, Published by North-Holland Publ., Amsterdam

Published
2022

13. Evolution of the gamma-ray strength function in neodymium isotopes

Author

M. Guttormsen, K. O. Ay, M. Ozgur, E. Algin, A. C. Larsen, F. L. Bello Garrote, H. C. Berg, L. Crespo Campo, T. Dahl-Jacobsen, F. W. Furmyr, D. Gjestvang, A. Görgen, T. W. Hagen, V. W. Ingeberg, B. V. Kheswa, I. K. B. Kullmann, M. Klintefjord, M. Markova, J. E. Midtbø, V. Modamio, W. Paulsen, L. G. Pedersen, T. Renstrøm, E. Sahin, S. Siem, G. M. Tveten, and M. Wiedeking

Subjects
Nuclear Theory, Astrophysics::High Energy Astrophysical Phenomena, Modes, Dipole, Nuclear Experiment
Abstract

The experimental gamma-ray strength functions (gamma-SFs) of 142,144-151Nd have been studied for gamma-ray energies up to the neutron separation energy. The results represent a unique set of gamma-SFs for an isotopic chain with increasing nuclear deformation. The data reveal how the low-energy enhancement, the scissors mode and the pygmy dipole resonance evolve with nuclear deformation and mass number. The data indicate that the mechanisms behind the low-energy enhancement and the scissors mode are decoupled from each other., Comment: 14 pages and 10 figures

Published
2022

14. Experimental Level Scheme of \(^{78}\)Cu

Author

L.G. Pedersen, E. Sahin, A. Görgen, F.L. Bello Garrote, Y. Tsunoda, T. Otsuka, M. Niikura, S. Nishimura, Z. Xu, H. Baba, G. Benzoni, F. Browne, A.M. Bruce, S. Ceruti, F.C.L. Crespi, R. Daido, G. de Angelis, M.-C. Delattre, Zs. Dombradi, P. Doornenbal, Y. Fang, S. Franchoo, G. Gey, A. Gottardo, T. Isobe, P.R. John, H.S. Jung, I. Kojouharov, T. Kubo, N. Kurz, I. Kuti, Z. Li, G. Lorusso, I. Matea, K. Matsui, D. Mengoni, T. Miyazaki, V. Modamio, S. Momiyama, A.I. Morales, P. Morfouace, D.R. Napoli, F. Naqvi, H. Nishibata, A. Odahara, R. Orlandi, Z. Patel, S. Rice, H. Sakurai, H. Schaffner, L. Sinclair, P.-A. Söderström, D. Sohler, I.G. Stefan, T. Sumikama, D. Suzuki, R. Taniuchi, J. Taprogge, Z. Vajta, J.J. Valiente-Dobón, H. Watanabe, V. Werner, J. Wu, A. Yagi, M. Yalcinkaya, R. Yokoyama, and K. Yoshinaga

Subjects
General Physics and Astronomy
Published
2023

15. High-spin intruder states in the mirror nuclei S31 and P31

Author

M. Rocchini, M. Siciliano, R. Menegazzo, P. R. John, D. Bazzacco, J. J. Valiente-Dobón, A. Mentana, D. A. Testov, A. Nannini, G. Colucci, A. Gozzelino, F. Recchia, D. Mengoni, F. Galtarossa, K. Hadynska-Klek, D. R. Napoli, A. Boso, M. Palacz, V. Modamio, F. Nowacki, M. Cottini, S. M. Lenzi, G. Jaworski, S. Lunardi, G. de Angelis, and A. Goasduff

Subjects
Physics, Condensed matter physics, 010308 nuclear & particles physics, 0103 physical sciences, Mirror nuclei, 010306 general physics, Spin (physics), 01 natural sciences
Published
2021

16. High resolution gamma-ray spectrometry using GALILEO array

Author

D. Testov, J.J. Valiente-Dobon, D. Mengoni, F. Recchia, A. Goasduff, A. Boso, S. Lenzi, G. de Angelis, S. Bakes, C. Boiano, B. Cederwall, G. Colucci, M. Cicerchia, P. Colovic, F. Didierjean, M. Doncel, J.A. Duenas, F. Galtarossa, A. Gozzelino, K. Hadynska-Klek, R. Isocrate, G. Jaworski, P.R. John, H. Liu, S. Lunardi, R. Menegazzo, A. Mentana, V. Modamio, A. Nannini, D.R. Napoli, M. Palacz, G. Pasqualato, M. Rocchini, S. Riccetto, B. Saygi, E. Sahin, M. Siciliano, Yu. Sobolev, and S. Szilner

Subjects
Physics, γ -ray spectrometer, Nuclear and High Energy Physics, Radiation, Physics and Astronomy (miscellaneous), business.industry, Materials Science (miscellaneous), High resolution, γ -ray spectroscopy, nuclearstate lifetime, Condensed Matter Physics, lcsh:QC1-999, Optics, nuclear structure, Galileo (vibration training), business, lcsh:Physics, Gamma ray spectrometry
Abstract

The GALILEO γ -ray spectrometer has been constructed at the Legnaro National Laboratory of INFN (LNL-INFN). It can be coupled to advanced ancillary devices which allows nuclear structure studies employing the variety of in-beam γ -ray spectroscopy methods. Such studies benefit from reactions induced by the intense stable beams delivered by the Tandem-ALPI-PIAVE accelerator complex and by the radioactive beams which will be provided by the SPES facility. In this paper we outline two experiments performed within the experimental campaign at GALILEO coupled to the EUCLIDES Si-ball and the Neutron Wall array. The first one was aimed at spectroscopic studies in A=31 mirror nuclei and the second one at measurements of lifetimes of excited states in nuclei in the vicinity of 100 Sn.

Published
2019

17. Neutron detection and γ-ray suppression using artificial neural networks with the liquid scintillators BC-501A and BC-537

Author

K. Hadyńska-Klȩk, G. de Angelis, A. Goasduff, Sara Carturan, Jorge Agramunt, A. Triossi, D. A. Testov, S. Erturk, V. Modamio, R. Wadsworth, J. J. Valiente Dobon, J. Egea, P. A. Söderström, M. N. Erduran, A. Gadea, T. Hüyük, Marek Moszynski, Enrique Sanchis, M. Palacz, Vicente González, Norbert Pietralla, A. Di Nitto, Johan Nyberg, and G. Jaworski

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Artificial neural network, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Scintillator, 01 natural sciences, Computational physics, Recoil, Deuterium, 0103 physical sciences, Neutron detection, Neutron, 010306 general physics, Spectroscopy, Instrumentation
Abstract

In this work we present a comparison between the two liquid scintillators BC-501A and BC-537 in terms of their performance regarding the pulse-shape discrimination between neutrons and γ rays. Special emphasis is put on the application of artificial neural networks . The results show a systematically higher γ -ray rejection ratio for BC-501A compared to BC-537 applying the commonly used charge comparison method. Using the artificial neural network approach the discrimination quality was improved to more than 95% rejection efficiency of γ rays over the energy range 150 to 1000 keV for both BC-501A and BC-537. However, due to the larger light output of BC-501A compared to BC-537, neutrons could be identified in BC-501A using artificial neural networks down to a recoil proton energy of 800 keV compared to a recoil deuteron energy of 1200 keV for BC-537. We conclude that using artificial neural networks it is possible to obtain the same γ -ray rejection quality from both BC-501A and BC-537 for neutrons above a low-energy threshold. This threshold is, however, lower for BC-501A, which is important for nuclear structure spectroscopy experiments of rare reaction channels where low-energy interactions dominates.

Published
2019

18. The GALILEO γ-ray array at the Legnaro National Laboratories

Author

R. Menegazzo, I. Zanon, F. Veronese, D.A. Testov, J. Ha, N. Bez, B. Million, G. Pasqualato, Alberto Pullia, M. Biasotto, L. Ramina, S. Bottoni, C. A. Ur, M. L. Cortés, D. Mengoni, S. Coelli, G. Gosta, C. Fanin, M. Siciliano, A. Saltarelli, D. Bazzacco, D. Tomasella, J. J. Valiente-Dobón, S. Leoni, M. Romanato, S. Ventura, A. Gadea, N. Toniolo, Marco Bellato, Diego Barrientos, S. Brambilla, D. Brugnara, R.M. Pérez-Vidal, F. Recchia, F. C. L. Crespi, F.J. Egea, S. Lunardi, S. Capra, M. Rebeschini, S. Fantinel, G. Jaworski, A. Bracco, M. Gulmini, G. Rampazzo, M. Scarcioffolo, N. Blasi, J. Pellumaj, S. Pigliapoco, G. Benzoni, V. Volpe, P. Cocconi, A. Boso, O. Wieland, K. Hadyńska-Klȩk, E.R. Gamba, A. Capsoni, A. Gambalonga, E. Viscione, F. Camera, G. de Angelis, A. Nannini, Roberto Isocrate, C. Boiano, A. Illana, M. Rocchini, G. Zhang, A. Gottardo, A. Goasduff, C. Gesmundo, P. R. John, N. Marchini, S. Ziliani, K. Rezynkina, D. R. Napoli, E. Gregor, A. Gozzelino, D. Rosso, M. Rampazzo, V. Modamio, M. Polettini, M. Magalini, F. Tomasi, S. M. Lenzi, and C. Porzio

Subjects
Physics, Nuclear and High Energy Physics, Silicon, business.industry, Instrumentation, High-resolution γ-ray spectroscopy, Detector, Neutron, DAQ, Electronics, HPGe, Semiconductor detector, Optics, Data acquisition, Galileo (vibration training), business, Hpge detector
Abstract

GALILEO, a new 4 π high-resolution γ -detection array, based on HPGe detectors, has been developed and installed at the Legnaro National Laboratories. The GALILEO array greatly benefits from a fully-digital read-out chain, customized DAQ, and a variety of complementary detectors to improve the resolving power by the detection of particles, ions or high-energy γ -ray transitions. In this work, a full description of the array, including electronics and DAQ, is presented together with its complementary instrumentation.

Published
2021

19. Strong enhancement of level densities in the crossover from spherical to deformed neodymium isotopes

Author

E. Algin, Fabio Zeiser, F. L. Bello Garrote, Andreas Görgen, V. W. Ingeberg, M. Klintefjord, Trine Wiborg Hagen, Wouter Ryssens, Gry Merete Tveten, Yoram Alhassid, B. V. Kheswa, E. Sahin, L. Crespo Campo, Ann-Cecilie Larsen, V. Modamio, M. Ozgur, Therese Renstrøm, Sunniva Siem, J. E. Midtbø, T. Dahl-Jacobsen, Magne Guttormsen, and K. O. Ay

Subjects
Nuclear and High Energy Physics, Monte Carlo method, Crossover, Nuclear Theory, FOS: Physical sciences, chemistry.chemical_element, Collective enhancement, 01 natural sciences, Neodymium, Molecular physics, 0103 physical sciences, Neutron, Mean-field theory, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Isotope, Oslo method, 010308 nuclear & particles physics, Shell model Monte Carlo, lcsh:QC1-999, chemistry, Mean field theory, Nuclear level density, Saturation (chemistry), lcsh:Physics, Excitation
Abstract

Understanding the evolution of level densities in the crossover from spherical to well-deformed nuclei has been a long-standing problem in nuclear physics. We measure nuclear level densities for a chain of neodymium isotopes $^{142,144-151}$Nd which exhibit such a crossover. These results represent to date the most complete data set of nuclear level densities for an isotopic chain between neutron shell-closure and towards mid-shell. We observe a strong increase of the level densities along the chain with an overall increase by a factor of $\approx 170$ at an excitation energy of 7.5 MeV and saturation around mass 150. Level densities calculated by the shell model Monte Carlo (SMMC) are in excellent agreement with these experimental results. Based on our experimental and theoretical findings, we offer an explanation of the observed mass dependence of the level densities in terms of the intrinsic single-particle level density and the collective enhancement., 7 pages, 4 figures

Published
2021

20. The Oslo Cyclotron Laboratory

Author

Gjermund Henriksen, Sunniva Siem, A. C. Larsen, Theodossis A. Theodossiou, Erik Adli, Magne Guttormsen, H. Gjersdal, Jon Christopher Wikne, Bent W. Schoultz, Andreas Görgen, P. A. Sobas, Eirik Malinen, V. Modamio, and Nina Jeppesen Edin

Subjects
Fluid Flow and Transfer Processes, Engineering, 010308 nuclear & particles physics, business.industry, Nuclear engineering, Cyclotron, General Physics and Astronomy, 01 natural sciences, law.invention, law, 0103 physical sciences, Nuclear astrophysics, 010306 general physics, business
Abstract

Research at the Oslo Cyclotron Laboratory at the University of Oslo is focused on spectroscopy experiments for nuclear structure and nuclear astrophysics using the Oslo Scintillator Array OSCAR. Light-ion beams from the$$K=35$$K=35cyclotron are furthermore used for studies in radiation biology and medical physics, for research and development related to medical isotope production, and for irradiation of materials and electronics components. Here we present an overview of the laboratory and its research infrastructure, give a brief discussion of the respective research programs and methods, and present recent highlights.

Published
2021

21. Lifetimes of core-excited states in semi-magic $$^{95}\mathrm {Rh}$$

Author

G. de Angelis, Eric Clément, Bo Cederwall, H. Al Azri, Mikael Sandzelius, Ulrika Jakobsson, C. M. Petrache, Chong Qi, S. S. Ghugre, V. Modamio, Zhigang Xiao, F. Ghazi Moradi, S. Erturk, G. Jaworski, Baki Akkuş, A. Algora, A. Ertoprak, M. Palacz, M. Doncel, C. Michelagnoli, Torbjörn Bäck, Eiji Ideguchi, A. Boso, H. W. Li, J. J. Valiente-Dobón, M. Siciliano, Zs. Dombradi, A. Gadea, T. Hüyük, Johan Nyberg, F. Recchia, R. Wadsworth, B. M. Nyakó, P. J. Davies, István Kuti, D. M. Debenham, D. R. Napoli, D. Sohler, A. Gottardo, János Timár, R. Raut, A. Atac, Department of Physics [Stockholm], Royal Institute of Technology [Stockholm] (KTH ), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-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), and Department of Physics, Royal Institute of Technology (KTH), 10691 Stockholm, Sweden

Subjects
[PHYS]Physics [physics], Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Hadron, 01 natural sciences, Core (optical fiber), symbols.namesake, Excited state, 0103 physical sciences, symbols, Nuclear fusion, Neutron, MAGIC (telescope), Atomic physics, 010306 general physics, Doppler effect, Line (formation)
Abstract

Lifetimes of negative-parity states have been determined in the neutron deficient semi-magic (N = 50) nucleus $$^{95}\mathrm {Rh}$$ 95 Rh . The fusion-evaporation reaction $$^{58}Ni(^{40}Ca, 3p)$$ 58 N i ( 40 C a , 3 p ) was used to populate high-spin states in $$^{95}\mathrm {Rh}$$ 95 Rh at the Grand Accélérateur National d’Ions Lourds (GANIL) accelerator facility. The results were obtained using the Doppler Shift Attenuation Method (DSAM) based on the Doppler broadened line shapes produced during the slowing down process of the residual nuclei in a thick $$6\;\mathrm {mg/cm}^2$$ 6 mg / cm 2 metallic target. B(M1) and B(E2) reduced transition strengths are compared with predictions from large-scale shell-model calculations.

Published
2020

22. Transition strengths in the neutron-rich Ni73,74,75 isotopes

Author

P. A. Söderström, T. Furumoto, K. Kaneko, D. Mengoni, J. J. Valiente-Dobón, K. Matsui, István Kuti, Nunzio Itaco, Yoshiaki Shiga, Zhengyu Xu, G. de Angelis, F. Browne, Dóra Sohler, S. Ceruti, A. Gargano, Zs. Vajta, D. R. Napoli, Rin Yokoyama, M. Yalcinkaya, L. Coraggio, Satoshi Takeuchi, H. Liu, R. Orlandi, V. Modamio-Hoybjor, Jinguang Wu, E. Sahin, L. Sinclair, Ryo Taniuchi, F. L. Bello Garrote, F. C. L. Crespi, T. Isobe, G. Benzoni, P. Doornenbal, Stephen Rice, A. Gottardo, Jenny Lee, Satoru Momiyama, Hiroshi Watanabe, D. Fang, Giuseppe Lorusso, Hiroyoshi Sakurai, Jan Taprogge, M. C. Delattre, Masafumi Matsushita, R. Avigo, Megumi Niikura, T. Motobayashi, B. Melon, O. Wieland, R. Daido, Zs. Dombrádi, H. Wang, N. Blasi, H. Baba, Toshiyuki Sumikama, Z. Patel, Shunji Nishimura, Tsuyoshi Miyazaki, and P. Van Isacker

Subjects
Physics, Proton, Isotope, 010308 nuclear & particles physics, Shell (structure), Coulomb excitation, 01 natural sciences, medicine.anatomical_structure, 0103 physical sciences, medicine, Neutron, Atomic physics, 010306 general physics, Nucleus, Excitation, Line (formation)
Abstract

Reduced transition probabilities have been measured for the neutron-rich Ni73,74,75 nuclei with relativistic Coulomb excitation performed at the RIKEN Nishina Center. For the even-even Ni isotope the determined B(E2;0+→2+) value is compatible within errors with the result of a previous intermediate energy Coulomb excitation experiment, although being somewhat larger. For the odd Ni isotopes B(E2) values have been determined for the first time. In the middle νg9/2 shell nucleus Ni73 three peak candidates have been observed and tentatively assigned to the (5/2+), (13/2+), and (11/2+) excitations. Two peak candidates have been observed in Ni75 and tentatively assigned to the (13/2+) and (11/2+) levels. The measured B(E2) values are in line with the large B(E2) reported in Ni70 and at variance with the small strength measured in Ni72. Excitation energies compare well with the result of large-scale shell-model calculations, while B(E2) values are larger than predicted. This could indicate an increasing contribution of proton excitations across the Z=28 shell closure when approaching Ni78.

Published
2020

23. g factor of the $12^+$K-isomer in $^{174}$W

Author

F. Camera, A. I. Morales, E. Vigezzi, O. Wieland, C. Michelagnoli, R. Menegazzo, P. Sona, J. J. Valiente-Dobón, D. Bazzacco, A. Nannini, S. Bottoni, Georgi P. Georgiev, D. R. Napoli, S. Ceruti, G. Bocchi, N. Blasi, Luna Pellegri, V. Modamio, C. A. Ur, M. Rocchini, S. Leoni, B. Million, R. Avigo, A. Perego, B. Melon, D. Mengoni, A. Bracco, G. Benzoni, Agnese Giaz, A. Gottardo, F. C. L. Crespi, M. Ottanelli, E. R. Gamba, P. R. John, S. Capra, 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 Laue-Langevin (ILL), ILL, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, g factor, Landé g-factor, Hadron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Tunnel effect, 0103 physical sciences, Quadrupole, Nuclear fusion, Atomic physics, 010306 general physics, Ground state, Dimensionless quantity
Abstract

The g factor of the $$12^+$$ K-isomer in $$^{174}$$ W has been measured by means of the time-differential perturbed angular distribution technique as $$g(12^+)=+0.304(11)$$ . In addition, the half-life of the isomer has been remeasured as $$T_{1/2}(12^+)=124(8)$$ ns, in agreement with the literature value and confirming the anomalous hindrance F of the E2 transition to the $$10^+$$ level of the ground state band with respect to the $$\gamma $$ -tunnelling model prediction. The measured g factor has been compared with estimates based on experimental g factors from odd-mass isotopes in the same mass region and with Nilsson model calculations. The results establish unique features of the $$12^+$$ K-isomer in $$^{174}$$ W, which can possess a non-pure intrinsic configuration and/or can be characterised by values of the intrinsic quadrupole moment $$Q_0$$ and the rotational g factor $$g_R$$ significantly different with respect to the majority of K-isomers at mass $$A \approx 180$$ .

Published
2020

24. 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

25. Evidence for octupole collectivity in $^{172}{\mathrm {Pt}}$

Author

E. Ganioglu, Rauno Julin, I. Özgür, R. D. Page, Eiji Ideguchi, O. Aktas, Sanna Stolze, E. S. Paul, J. Hilton, Torbjörn Bäck, H. W. Li, J. J. Valiente-Dobón, S. Matta, Mikael Sandzelius, Steffen Ketelhut, B. S. Nara Singh, Panu Rahkila, Tuomas Grahn, U. Jakobsson, Panu Ruotsalainen, C. M. Petrache, Megumi Niikura, D. M. Cullen, Jari Partanen, K. Andgren, Janne Pakarinen, Bo Cederwall, A. Ertoprak, B. Hadinia, D. Hodge, M. Kumar Raju, T. Calverley, Juha Sorri, Juha Uusitalo, V. Modamio, H. Badran, Paul Greenlees, Chong Qi, M. Nyman, Pauli Peura, Daniel Cox, A. Johnson, Jan Sarén, Y. D. Fang, Peter M. Jones, Michael Taylor, Matti Leino, Ramon Wyss, Thomas Braunroth, Catherine Scholey, H. Liu, Sakari Juutinen, Roberto Liotta, M. B. Gomez Hornillos, M. Doncel, M. M. Giles, P. Subramaniam, Philippos Papadakis, Anton Khaplanov, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), 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, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, medicine.anatomical_structure, Excited state, 0103 physical sciences, medicine, Nuclear fusion, 010306 general physics, Nucleus, Excitation
Abstract

Excited states in the extremely neutron-deficient nucleus $$^{172}{\mathrm {Pt}}$$172Pt were populated via $$^{96}\mathrm {Ru}(^{78}\mathrm {Kr},2p)$$96Ru(78Kr,2p) and $$^{92}\mathrm {Mo}(^{83}\mathrm {Kr},3n)$$92Mo(83Kr,3n) reactions. The level scheme has been extended up to an excitation energy of $$\approx 5~\hbox {MeV}$$≈5MeV and tentative spin-parity assignments up to $$I^\pi = 18^+$$Iπ=18+. Linear polarization and angular distribution measurements were used to determine the electromagnetic E1 character of the dipole transitions connecting the positive-parity ground-state band with an excited side-band, firmly establishing it as a negative-parity band. The lowest member of this negative-parity structure was firmly assigned spin-parity $$3^-$$3-. In addition, we observed an E3 transition from this $$3^-$$3- state to the ground state, providing direct evidence for octupole collectivity in $$^{172}{\mathrm {Pt}}$$172Pt. Large-scale shell model (LSSM) and total Routhian surface (TRS) calculations have been performed, supporting the interpretation of the $$3^-$$3- state as a collective octupole-vibrational state.

Published
2020

26. Lifetime measurements of N≃20 phosphorus isotopes using the AGATA γ -ray tracking spectrometer

Author

L. Capponi, A. Gottardo, S. Courtin, E. Fioretto, K. Mulholland, D. Bazzacco, Alain Goasduff, D. Montanari, B. Melon, X. Derkx, F. Haas, A. Pipidis, Tea Mijatović, Thomas Braunroth, A. M. Stefanini, L. Grocutt, Suzana Szilner, C. Michelagnoli, G. Montagnoli, E. Sahin, L. Corradi, V. Liberati, J. J. Valiente-Dobón, D. R. Napoli, P. Désesquelles, C. M. Petrache, Maria Doncel, F. Recchia, M. Bouhelal, D. Mengoni, Robert Chapman, Pushpendra Singh, V. Modamio, and J. F. Smith

Subjects
Physics, Spectrometer, 010308 nuclear & particles physics, Nuclear structure, Isotopes of phosphorus, Phosphorus Isotopes, 01 natural sciences, Ion, Excited state, 0103 physical sciences, AGATA, Atomic physics, 010306 general physics, Ground state
Abstract

Lifetimes of excited states of the phosphorus isotopes 1533,34,35,36P have been measured by using the differential recoil-distance method. The isotopes of phosphorus were populated in binary grazing reactions initiated by a beam of S36 ions of energy 225 MeV incident on a thin Pb208 target mounted in the Cologne plunger apparatus. The combination of the PRISMA magnetic spectrometer and an early implementation of the AGATA γ-ray tracking array was used to detect γ rays in coincidence with projectile-like nuclear species. Lifetime measurements of populated states were made within the range from about 1 to 100 ps. The number of states for which lifetime measurements were possible was limited by statistics. For P33, lifetime limits were determined for the first 3/2+ and 5/2+ states at 1431 and 1848 keV, respectively; the results are compared with previous published lifetime values. The lifetime of the first 2+ state of P34 at 429 keV was determined and compared with earlier measurements. For P35, the states for which lifetimes, or lifetime limits, were determined were those at 2386, 3860, 4101, and 4493 keV, with Jπ values of 3/2+, 5/2+, 7/21−, and 7/22−, respectively. There have been no previous published lifetimes for states in this nucleus. A lifetime was measured for the stretched π(1f7/2)⊗ν(1f7/2)Jπ=(7+) state of P36 at 5212 keV and a lifetime limit was established for the stretched π(1d3/2)⊗ν(1f7/2)Jπ=(5−) state at 2030 keV. There are no previously published lifetimes for states of P36. Measured lifetime values were compared with the results of state-of-the-art shell-model calculations based on the PSDPF effective interaction. In addition, measured branching ratios, published mixing ratios, and electromagnetic transition rates, where available, have been compared with shell-model values. In general, there is good agreement between experiment and the shell model; however there is evidence that the shell-model values of the M1 transition rates for the 3/21+→1/2+ (ground state) and 5/21+→3/21+ transitions in P33 underestimate the experimental values by a factor between 5 and 10. In P35 there are some disagreements between experimental and shell-model values of branching ratios for the first and second excited 7/2− states. In particular, there is a serious disagreement for the decay characteristics of the second 7/2− state at 4493 keV, for which the shell-model counterpart lies at 4754 keV. In this case, the shell-model competing electromagnetic decay branches are dominated by E1 and M1 transitions.

Published
2019

27. Type II shell evolution in A = 70 isobars from the N ≥ 40 island of inversion

Author

G. de Angelis, A. I. Morales, A. Gottardo, Zs. Dombradi, A. Bracco, Zhengyu Xu, Pieter Doornenbal, E. Sahin, Shunji Nishimura, Hiroyoshi Sakurai, H. Schaffner, R. Orlandi, F. C. L. Crespi, Giuseppe Lorusso, N. Blasi, K. Matsui, N. Kurz, P. A. Söderström, Y. F. Fang, S. Ceruti, R. Avigo, Tadashi Miyazaki, R. Taniuchi, R. Daido, Jan Taprogge, V. Modamio-Hoybjor, Jin Wu, Yusuke Tsunoda, G. Benzoni, Zena Patel, F. Camera, Rin Yokoyama, István Kuti, F. Browne, D. R. Napoli, B. Melon, Stephen Rice, Takaharu Otsuka, Megumi Niikura, Toshiyuki Sumikama, J. J. Valiente-Dobón, Hidetada Baba, Oliver Wieland, F. L. Bello Garrote, Hirofumi Watanabe, L. Sinclair, M. Yalcinkaya, Ayumi Yagi, I. Kojouharov, Tadaaki Isobe, M. C. Delattre, Satoru Momiyama, D. Mengoni, D. Sohler, Zs. Vajta, 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), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and SCOAP

Subjects
Physics, Nuclear and High Energy Physics, education.field_of_study, 010308 nuclear & particles physics, Fission, Island of inversion, Population, Shell (structure), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, lcsh:QC1-999, Atomic orbital, 0103 physical sciences, Isobar, ddc:530, Atomic physics, 010306 general physics, Spectroscopy, education, lcsh:Physics, Excitation
Abstract

The level structures of 70 Co and 70 Ni, populated from the β decay of 70 Fe, have been investigated using β -delayed γ -ray spectroscopy following in-flight fission of a 238 U beam. The experimental results are compared to Monte-Carlo Shell-Model calculations including the pf+g9/2+d5/2 orbitals. The strong population of a (1+) state at 274 keV in 70 Co is at variance with the expected excitation energy of ∼1 MeV from near spherical single-particle estimates. This observation indicates a dominance of prolate-deformed intruder configurations in the low-lying levels, which coexist with the normal near spherical states. It is shown that the β decay of the neutron-rich A=70 isobars from the new island of inversion to the Z=28 closed-shell regime progresses in accordance with a newly reported type of shell evolution, the so-called Type II, which involves many particle-hole excitations across energy gaps. Elsevier

Published
2017

28. The New Neutron Multiplicity Filter NEDA and Its First Physics Campaign with AGATA

Author

G. Jaworski, A. Goasduff, F.J. Egea Canet, V. Modamio, T. Hüyük, A. Triossi, M. Jastrząb, P.-A. Söderström, S.M. Carturan, A. Di Nitto, G. de Angelis, G. De France, N. Erduran, A. Gadea, M. Moszyński, J. Nyberg, M. Palacz, J. Valiente, R. Wadsworth, R. Aliaga, C. Aufranc, M. Bézard, G. Beaulieu, P. Bednarczyk, E. Bisiato, A. Boujrad, I. Burrows, E. Clément, P. Cocconi, G. Colucci, D. Conventi, M. Cordwell, S. Coudert, J.M. Deltoro, L. Ducroux, T. Dupasquier, S. Ertürk, X. Fabian, V. González, A. Gottardo, A. Grant, K. Hadyńska-Klęk, A. Illana, M.L. Jurado-Gomez, M. Kogimtzis, I. Lazarus, L. Legeard, J. Ljungvall, A. Maj, G. Pasqualato, R.M. Pérez-Vidal, A. Raggio, D. Ralet, N. Redon, F. Saillant, E. Sanchis, B. Sayğı, M. Scarcioffolo, M. Siciliano, O. Stezowski, D. Testov, M. Tripon, I. Zanon, 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), 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), 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 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), Ege Üniversitesi, Jaworski, G., Goasduff, A., Egea Canet, F. J., Modamio, V., Hüyük, T., Triossi, A., Jastrząb, M., Söderström, P. -A., Carturan, S. M., Di Nitto, A., De Angelis, G., De France, G., Erduran, N., Gadea, A., Moszyński, M., Nyberg, J., Palacz, M., Valiente, J., Wadsworth, R., Aliaga, R., Aufranc, C., Bézard, M., Beaulieu, G., Bednarczyk, P., Bisiato, E., Boujrad, A., Burrows, I., Clément, E., Cocconi, P., Colucci, G., Conventi, D., Cordwell, M., Coudert, S., Deltoro, J. M., Ducroux, L., Dupasquier, T., Ertürk, S., Fabian, X., González, V., Gottardo, A., Grant, A., Hadyńska-Klęk, K., Illana, A., Jurado-Gomez, M. L., Kogimtzis, M., Lazarus, I., Legeard, L., Ljungvall, J., Maj, A., Pasqualato, G., Pérez-Vidal, R. M., Raggio, A., Ralet, D., Redon, N., Saillant, F., Sanchis, E., Sayğı, B., Scarcioffolo, M., Siciliano, M., Stezowski, O., Testov, D., Tripon, M., Zanon, I., Jaworski, G., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy, Heavy Ion Laboratory, University of Warsaw, Warszawa, Poland -- Goasduff, A., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy, Department of Physics and Astronomy, University of Padua, Padua, Italy, INFN, Division of Padua, Padua, Italy -- Egea Canet, F.J., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy, Department of Physics and Astronomy, University of Padua, Padua, Italy, INFN, Division of Padua, Padua, Italy, IFIC, CSIC University of Valencia, Paterna, Spain -- Modamio, V., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy, Department of Physics, University of Oslo, Oslo, Norway -- Hüyük, T., IFIC, CSIC University of Valencia, Paterna, Spain -- Triossi, A., Department of Physics and Astronomy, University of Padua, Padua, Italy, INFN, Division of Padua, Padua, Italy, CERN, Switzerland -- Jastrzab, M., Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland -- Söderström, P.-A., Extreme Light Infrastructure–Nucl. Phys. (ELI–NP), Bucharest, Romania -- Carturan, S.M., Department of Physics and Astronomy, University of Padua, Padua, Italy, INFN, Division of Padua, Padua, Italy -- Di Nitto, A., Helmholtz Institute Mainz and GSI, Darmstadt, Germany -- De Angelis, G., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy -- De France, G., GANIL, CEA/DSAM and CNRS/IN2P3, Caen, France -- Erduran, N., Fac. of Eng. and Natural Sciences, Istanbul Zaim University, Istanbul, Turkey -- Gadea, A., IFIC, CSIC University of Valencia, Paterna, Spain -- Moszynski, M., National Centre for Nuclear Research, Otwock-Swierk, Poland -- Nyberg, J., Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden -- Palacz, M., Heavy Ion Laboratory, University of Warsaw, Warszawa, Poland -- Valiente, J., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy -- Wadsworth, R., Department of Physics, University of York, Heslington, York, United Kingdom -- Aliaga, R., IFIC, CSIC University of Valencia, Paterna, Spain -- Aufranc, C., University of Lyon, CNRS, IN2P3, IPN Lyon, Villeurbanne, France -- Bézard, M., GANIL, CEA/DSAM and CNRS/IN2P3, Caen, France -- Beaulieu, G., University of Lyon, CNRS, IN2P3, IPN Lyon, Villeurbanne, France -- Bednarczyk, P., Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland -- Bisiato, E., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy -- Boujrad, A., GANIL, CEA/DSAM and CNRS/IN2P3, Caen, France -- Burrows, I. -- Clément, E., GANIL, CEA/DSAM and CNRS/IN2P3, Caen, France -- Cocconi, P., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy -- Colucci, G., Department of Physics and Astronomy, University of Padua, Padua, Italy, INFN, Division of Padua, Padua, Italy -- Conventi, D., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy -- Cordwell, M. -- Coudert, S., GANIL, CEA/DSAM and CNRS/IN2P3, Caen, France -- Deltoro, J.M., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy -- Ducroux, L., University of Lyon, CNRS, IN2P3, IPN Lyon, Villeurbanne, France -- Dupasquier, T., University of Lyon, CNRS, IN2P3, IPN Lyon, Villeurbanne, France -- Ertürk, S., Department of Physics, Nigde Omer Halisdemir University, Nigde, Turkey -- Fabian, X., University of Lyon, CNRS, IN2P3, IPN Lyon, Villeurbanne, France -- González, V., Department of Electric Engineering, University of Valencia, Burjassot, Spain -- Gottardo, A., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy -- Grant, A. -- Hadynska-Klek, K., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy, Department of Physics, University of Surrey, Guildford, United Kingdom -- Illana, A., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy -- Jurado-Gomez, M.L., IFIC, CSIC University of Valencia, Paterna, Spain -- Kogimtzis, M., qTFC Daresbury Laboratory, Daresbury, Warrington, United Kingdom -- Lazarus, I., qTFC Daresbury Laboratory, Daresbury, Warrington, United Kingdom -- Legeard, L., GANIL, CEA/DSAM and CNRS/IN2P3, Caen, France -- Ljungvall, J., CSNSM, CNRS, IN2P3, University Paris-Sud, Orsay, France -- Maj, A., Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland -- Pasqualato, G., Department of Physics and Astronomy, University of Padua, Padua, Italy, INFN, Division of Padua, Padua, Italy -- Pérez-Vidal, R.M., IFIC, CSIC University of Valencia, Paterna, Spain -- Raggio, A., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy, Department of Physics and Astronomy, University of Padua, Padua, Italy -- Ralet, D., GANIL, CEA/DSAM and CNRS/IN2P3, Caen, France -- Redon, N., University of Lyon, CNRS, IN2P3, IPN Lyon, Villeurbanne, France -- Saillant, F., GANIL, CEA/DSAM and CNRS/IN2P3, Caen, France -- Sanchis, E., Department of Electric Engineering, University of Valencia, Burjassot, Spain -- Sayğı, B., Ege University, Physics Department, Izmir, Turkey -- Scarcioffolo, M., INFN, Division of Padua, Padua, Italy -- Siciliano, M., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy -- Stezowski, O., University of Lyon, CNRS, IN2P3, IPN Lyon, Villeurbanne, France -- Testov, D., Department of Physics and Astronomy, University of Padua, Padua, Italy, INFN, Division of Padua, Padua, Italy -- Tripon, M., GANIL, CEA/DSAM and CNRS/IN2P3, Caen, France -- Zanon, I., Legnaro National Laboratories (LNL), INFN, Legnaro, Italy, and 0-Belirlenecek

Subjects
Physics, Spectrometer, 010308 nuclear & particles physics, business.industry, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, Neutron multiplicity, 01 natural sciences, 7. Clean energy, 0-Belirlenecek, Physics and Astronomy (all), Optics, Filter (video), 0103 physical sciences, AGATA, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics, business, Nuclear Experiment
Abstract

Zakopane Conference on Nuclear Physics - Extremes of the Nuclear Landscape -- AUG 26-SEP 02, 2018 -- Zakopane, POLAND, WOS: 000463866500047, A new neutron multiplicity filter NEDA, after a decade of design, R&D and construction, was employed in its first physics campaign with the AGATA spectrometer. Properties and performance of the array are discussed., Swedish Research CouncilSwedish Research Council [VR 2014-6644]; Scientific and Technological Research Council of Turkey (TUBITAK project)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [117F114, 114F473]; National Science Centre, Poland (NCN) [2017/25/B/ST2/01569, 2016/22/M/ST2/00269, 2014/14/M/ST2/00738, 2013/08/M/ST2/00257]; UK STFCScience & Technology Facilities Council (STFC) [ST/J000124/1, ST/L005727/1, STL005735/1, ST/P003885/1]; Generalitat Valenciana, SpainGeneralitat Valenciana; MICIU, Spain [PROM-ETEO II/2014/019, FPA2017-84756-C4, SEV-2014-0398]; E.C. FEDER fundsEuropean Union (EU), This study was supported by the Swedish Research Council (contract number VR 2014-6644), the Scientific and Technological Research Council of Turkey (TUBITAK project Nos. 117F114 and 114F473), the National Science Centre, Poland (NCN) (grants Nos. 2017/25/B/ST2/01569, 2016/22/M/ST2/00269, 2014/14/M/ST2/00738 and 2013/08/M/ST2/00257) the UK STFC under grant Nos. ST/J000124/1, ST/L005727/1, STL005735/1, ST/P003885/1, the Generalitat Valenciana and MICIU, Spain, grants PROM-ETEO II/2014/019, FPA2017-84756-C4, Severo Ochoa SEV-2014-0398 and by the E.C. FEDER funds.1

Published
2018

29. Pulse pile-up identification and reconstruction for liquid scintillator based neutron detectors

Author

Johan Nyberg, X.L. Luo, Enrique Sanchis, G. de Angelis, A. Triossi, M. Moszynski, R. Wadsworth, G. Jaworski, Q. Nishada, A. Gadea, T. Hüyük, P.-A. Söderström, M. Palacz, A. Di Nitto, V. Modamio, J. J. Valiente-Dobón, S. Erturk, F.J. Egea, J. Agramunt, A. Goasduff, M. N. Erduran, Vicente González, 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), 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), Luo, X. L., Modamio, V., Nyberg, J., Valiente-Dobon, J. J., Nishada, Q., de Angelis, G., Agramunt, J., Egea, F. J., Erduran, M. N., Erturk, S., de France, G., Gadea, A., Gonzalez, V., Goasduff, A., Huyuk, T., Jaworski, G., Moszynski, M., Di Nitto, A., Palacz, M., Soderstrom, P. -A., Sanchis, E., Triossi, A., and Wadsworth, R.

Subjects
Nuclear and High Energy Physics, Liquid scintillator, First-order derivative, Neutron-γ discrimination, 020209 energy, 02 engineering and technology, Derivative, Scintillator, Digital, 7. Clean energy, 01 natural sciences, Signal, Spectral line, Neutron-[formula omitted] discrimination, Optics, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Neutron detection, Neutron, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Instrumentation, Pile-up, Physics, Neutron-gamma discrimination, 010308 nuclear & particles physics, business.industry, Pulse (physics), Neutron- γ discrimination, business, Energy (signal processing)
Abstract

WOS: 000433206800010 The issue of pulse pile-up is frequently encountered in nuclear experiments involving high counting rates, which will distort the pulse shapes and the energy spectra. A digital method of off-line processing of pile-up pulses is presented. The pile-up pulses were firstly identified by detecting the downward-going zero-crossings in the first-order derivative of the original signal, and then the constituent pulses were reconstructed based on comparing the pile-up pulse with four models that are generated by combining pairs of neutron and.. standard pulses together with a controllable time interval. The accuracy of this method in resolving the pile-up events was investigated as a function of the time interval between two pulses constituting a pile-up event. The obtained results show that the method is capable of disentangling two pulses with a time interval among them down to 20 ns, as well as classifying them as neutrons or gamma rays. Furthermore, the error of reconstructing pile-up pulses could be kept below 6% when successive peaks were separated by more than 50 ns. By applying the method in a high counting rate of pile-up events measurement of the NEutron Detector Array (NEDA), it was empirically found that this method can reconstruct the pile-up pulses and perform neutron-gamma discrimination quite accurately. It can also significantly correct the distorted pulse height spectrum due to pile-up events. Swedish Research Council; UK STFC [ST/L005727/1]; Generalitat Valenciana, Spain [PROMETEO/2010/101]; MINECO, Spain [AIC-D-2011-0746, FPA2011-29854, FPA2012-33650]; TUBITAK, Turkey [114F473] This work was partly funded by the Swedish Research Council, by the UK STFC, under grant ST/L005727/1, by the Generalitat Valenciana, Spain, under grant PROMETEO/2010/101, by MINECO, Spain, under grants AIC-D-2011-0746, FPA2011-29854 and FPA2012-33650, and by TUBITAK, Turkey, under grant 114F473.

Published
2018

30. Neutron Skin Effects in Mirror Energy Differences: The Case of Mg23−Na23

Author

F. Ghazi-Moradi, K Juhász, Bo Cederwall, A. Boso, István Kuti, V. Modamio, P. R. John, A. Gadea, D. R. Napoli, T. Hüyük, M. A. Bentley, Johan Nyberg, S. M. Lenzi, T. W. Henry, B. M. Nyakó, Eric Clément, B. Melon, A. Dijon, Sibel Zehra Aydin, A. Gottardo, János Timár, J. Bonnard, Maria Doncel, G. Jaworski, M. Palacz, D. Mengoni, C. Michelagnoli, J. J. Valiente-Dobón, A. Di Nitto, A. P. Zuker, and F. Recchia

Subjects
Physics, Proton, 010308 nuclear & particles physics, Yrast, Nuclear Theory, Shell (structure), General Physics and Astronomy, 01 natural sciences, 0103 physical sciences, Orbit (dynamics), Neutron, Halo, Mirror nuclei, Atomic physics, Nuclear Experiment, 010306 general physics, Energy (signal processing)
Abstract

Energy differences between analogue states in the T=1/2 Mg23-Na23 mirror nuclei have been measured along the rotational yrast bands. This allows us to search for effects arising from isospin-symmetry-breaking interactions (ISB) and/or shape changes. Data are interpreted in the shell model framework following the method successfully applied to nuclei in the f7/2 shell. It is shown that the introduction of a schematic ISB interaction of the same type of that used in the f7/2 shell is needed to reproduce the data. An alternative novel description, applied here for the first time, relies on the use of an effective interaction deduced from a realistic charge-dependent chiral nucleon-nucleon potential. This analysis provides two important results: (i) The mirror energy differences give direct insight into the nuclear skin; (ii) the skin changes along the rotational bands are strongly correlated with the difference between the neutron and proton occupations of the s1/2 "halo" orbit.

Published
2018

31. Lifetime Measurements of Excited States in Pt172 and the Variation of Quadrupole Transition Strength with Angular Momentum

Author

H. Liu, Philippos Papadakis, Catherine Scholey, J. J. Valiente-Dobón, Rauno Julin, Joshua Hilton, Thomas Braunroth, D. Hodge, Juha Sorri, M. Doncel, S. Matta, Panu Ruotsalainen, Roberto Liotta, A. Ertoprak, D. M. Cullen, M. M. Giles, Daniel Cox, M. Kumar Raju, Panu Rahkila, C. M. Petrache, Sanna Stolze, H. J. Li, Tom Calverley, Jari Partanen, Tuomas Grahn, Janne Pakarinen, V. Modamio, Matthew J. Taylor, Juha Uusitalo, Sakari Juutinen, O. Aktas, Bo Cederwall, Eiji Ideguchi, Jan Sarén, Paul Greenlees, Chong Qi, H. Badran, Mikael Sandzelius, P. Subramaniam, and Y. D. Fang

Subjects
Physics, Quantum phase transition, Angular momentum, 010308 nuclear & particles physics, General Physics and Astronomy, 01 natural sciences, Excited state, Neutron number, 0103 physical sciences, Quadrupole, Nuclear fusion, Neutron, Interacting boson model, Atomic physics, 010306 general physics
Abstract

Lifetimes of the first excited 2(+) and 4(+) states in the extremely neutron -deficient nuclide Pt-172 have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2: 4(1)(+) -> 2(1)(+)/B(E2: 2(1)(+) -> 0(gs)(+)) = 0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segre chart. The observation adds to a cluster of a few extremely neutron -deficient nuclides of the heavy transition metals with neutron numbers N approximate to 90-94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2: 4(1)(+) -> 2(1)(+)/B(E2: 2(1)(+) -> 0(gs)(+)) ratios observed in these cases. Such low values cannot, e.g., be explained within the framework of the geometrical collective model or by algebraic approaches within the interacting boson model framework. It is proposed that the group of B(E2: 4(1)(+) -> 2(1)(+)/B(E2: 2(1)(+) -> 0(gs)(+)) ratios in the extremely neutron-deficient even-even W, Os, and Pt nuclei around neutron numbers N approximate to 90-94 reveal a quantum phase transition from a seniority-conserving structure to a collective regime as a function of neutron number. Although a system governed by seniority symmetry is the only theoretical framework for which such an effect may naturally occur, the phenomenon is highly unexpected for these nuclei that are not situated near closed shells.

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. Is Seniority a Partial Dynamic Symmetry in the First $\nu g_{9/2}$ Shell?

Author

Takaharu Otsuka, Toshiyuki Sumikama, Ryo Taniuchi, Giuseppe Lorusso, Zsolt Podolyak, R. Avigo, István Kuti, G. de Angelis, Shunji Nishimura, A. I. Morales, Nunzio Itaco, P. A. Söderström, D. R. Napoli, A. Gottardo, Yusuke Tsunoda, N. Blasi, Stephen Rice, Zena Patel, P. Van Isacker, Rin Yokoyama, I. Kojouharov, G. Benzoni, V. Modamio-Hoybjor, Jinguang Wu, Zs. Dombradi, F. Browne, F. L. Bello Garrote, T. Isobe, Jan Taprogge, E. Sahin, S. Lalkovski, Satoru Momiyama, L. Coraggio, N. Kurz, Hiroyoshi Sakurai, Tsuyoshi Miyazaki, P. Doornenbal, Oliver Wieland, M. Yalcinkaya, B. Melon, Ayumi Yagi, R. Daido, F. Camera, R. Orlandi, P. H. Regan, Y. F. Fang, A. Gargano, Hirofumi Watanabe, K. Matsui, H. Schaffner, D. Mengoni, F. C. L. Crespi, M. C. Delattre, J. J. Valiente-Dobón, A. Bracco, H. Baba, Zs. Vajta, Dóra Sohler, S. Ceruti, Megumi Niikura, Zhengyu Xu, Alison Bruce, L. Sinclair, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds ( GANIL ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Physique Nucléaire d'Orsay ( IPNO ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Morales, A. I., Benzoni, G., Watanabe, H., de Angelis, G., Nishimura, S., Coraggio, L., Gargano, A., Itaco, N., Otsuka, T., Tsunoda, Y., Van Isacker, P., Browne, F., Daido, R., Doornenbal, P., Fang, Y., Lorusso, G., Patel, Z., Rice, S., Sinclair, L., Söderström, P. -A., Sumikama, T., Valiente-Dobón, J. J., Wu, J., Xu, Z. Y., Yagi, A., Yokoyama, R., Baba, H., Avigo, R., Bello Garrote, F. L., Blasi, N., Bracco, A., Bruce, A. M., Camera, F., Ceruti, S., Crespi, F. C. L., Delattre, M. -C., Dombradi, Zs., Gottardo, A., Isobe, T., Kojouharov, I., Kurz, N., Kuti, I., Lalkovski, S., Matsui, K., Melon, B., Mengoni, D., Miyazaki, T., Modamio-Hoybjor, V., Momiyama, S., Napoli, D. R., Niikura, M., Orlandi, R., Podolyák, Zs., Regan, P. H., Sakurai, H., Sahin, E., Sohler, D., Schaffner, H., Taniuchi, R., Taprogge, J., Vajta, Zs., Wieland, O., Yalcinkaya, M., 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), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Nuclear and High Energy Physics, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Hadron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 29.30.Kv, 23.40.-s, Nuclear physics, 21.60.Cs, 0103 physical sciences, Neutron, Seniority, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Nuclear Experiment, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th], Spin-½, Physics, 010308 nuclear & particles physics, 23.20.Lv, Fermion, Quantum number, lcsh:QC1-999, Atomic physics, Nucleon, lcsh:Physics, Radioactive decay
Abstract

The low-lying structures of the midshell νg9/2 Ni isotopes 72Ni and 74Ni have been investigated at the RIBF facility in RIKEN within the EURICA collaboration. Previously unobserved low-lying states were accessed for the first time following β decay of the mother nuclei 72Co and 74Co. As a result, we provide a complete picture in terms of the seniority scheme up to the first (8+) levels for both nuclei. The experimental results are compared to shell-model calculations in order to define to what extent the seniority quantum number is preserved in the first neutron g9/2 shell. We find that the disappearance of the seniority isomerism in the (81+) states can be explained by a lowering of the seniority-four (6+) levels as predicted years ago. For 74Ni, the internal de-excitation pattern of the newly observed (62+) state supports a restoration of the normal seniority ordering up to spin J=4. This property, unexplained by the shell-model calculations, is in agreement with a dominance of the single-particle spherical regime near 78Ni. The low-lying structures of the midshell νg9/2 Ni isotopes 72Ni and 74Ni have been investigated at the RIBF facility in RIKEN within the EURICA collaboration. Previously unobserved low-lying states were accessed for the first time following β decay of the mother nuclei 72Co and 74Co. As a result, we provide a complete picture in terms of the seniority scheme up to the first (8+) levels for both nuclei. The experimental results are compared to shell-model calculations in order to define to what extent the seniority quantum number is preserved in the first neutron g9/2 shell. We find that the disappearance of the seniority isomerism in the (81+) states can be explained by a lowering of the seniority-four (6+) levels as predicted years ago. For 74Ni, the internal de-excitation pattern of the newly observed (62+) state supports a restoration of the normal seniority ordering up to spin J=4. This property, unexplained by the shell-model calculations, is in agreement with a dominance of the single-particle spherical regime near 78Ni. ispartof: Physics Letters B vol:781 pages:706-712 status: published

Published
2018

34. M1 and E2 transition rates from core-excited states in semi-magic 94Ru

Author

V. Modamio, F. Ghazi Moradi, Ulrika Jakobsson, Bo Cederwall, Torbjörn Bäck, H. W. Li, J. J. Valiente-Dobón, M. Siciliano, S. Erturk, István Kuti, Chong Qi, Eiji Ideguchi, D. R. Napoli, C. Michelagnoli, S. S. Ghugre, A. Gottardo, R. Wadsworth, János Timár, R. Raut, Zs. Dombradi, M. Doncel, A. Algora, A. Boso, G. Jaworski, G. de Angelis, P. J. Davies, Zhigang Xiao, D. M. Debenham, H. Al Azri, C. M. Petrache, A. Atac, Eric Clément, Baki Akkuş, F. Recchia, Mikael Sandzelius, A. Gadea, T. Hüyük, A. Ertoprak, M. Palacz, Johan Nyberg, B. M. Nyakó, Ertoprak, A., Department of Physics, Royal Institute of Technology (KTH), Stockholm, SE-10691, Sweden, Department of Physics, Faculty of Science, Istanbul University, Vezneciler/Fatih, Istanbul, 34134, Turkey -- Cederwall, B., Department of Physics, Royal Institute of Technology (KTH), Stockholm, SE-10691, Sweden -- Qi, C., Department of Physics, Royal Institute of Technology (KTH), Stockholm, SE-10691, Sweden -- Doncel, M., Department of Physics, Royal Institute of Technology (KTH), Stockholm, SE-10691, Sweden, Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 7ZE, United Kingdom -- Jakobsson, U., Department of Physics, Royal Institute of Technology (KTH), Stockholm, SE-10691, Sweden, Department of Chemistry, University of Helsinki, P.O. Box 3, Helsinki, 00014, Finland -- Nyakó, B.M., MTA Atomki, Debrecen, H-4001, Hungary -- Jaworski, G., Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, I-35020, Italy -- Davies, P., Department of Physics, University of York, Heslington, York, YO10 5DD, United Kingdom -- de France, G., Grand Accélérateur National d’Ions Lourds (GANIL), CEA/DSM - CNRS/IN2P3, Bd Henri Becquerel, BP 55027, Caen Cedex 5, F-14076, France -- Kuti, I., MTA Atomki, Debrecen, H-4001, Hungary -- Napoli, D.R., Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, I-35020, Italy -- Wadsworth, R., Department of Physics, University of York, Heslington, York, YO10 5DD, United Kingdom -- Ghugre, S.S., UGC-DAE Consortium for Scientific Research, Kolkata Centre, Kolkata, 700098, India -- Raut, R., UGC-DAE Consortium for Scientific Research, Kolkata Centre, Kolkata, 700098, India -- Akkus, B., Department of Physics, Faculty of Science, Istanbul University, Vezneciler/Fatih, Istanbul, 34134, Turkey -- Al Azri, H., Department of Physics, University of York, Heslington, York, YO10 5DD, United Kingdom -- Algora, A., MTA Atomki, Debrecen, H-4001, Hungary, Instituto de Física Corpuscular, CSIC-Universidad de Valencia, Valencia, E-46980, Spain -- de Angelis, G., Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, I-35020, Italy -- Atac, A., Department of Physics, Royal Institute of Technology (KTH), Stockholm, SE-10691, Sweden -- Bäck, T., Department of Physics, Royal Institute of Technology (KTH), Stockholm, SE-10691, Sweden -- Boso, A., Dipartimento di Fisica e Astronomia, Università di Padova, Padova, Italy -- Clément, E., Grand Accélérateur National d’Ions Lourds (GANIL), CEA/DSM - CNRS/IN2P3, Bd Henri Becquerel, BP 55027, Caen Cedex 5, F-14076, France -- Debenham, D.M., Department of Physics, University of York, Heslington, York, YO10 5DD, United Kingdom -- Dombrádi, Z., MTA Atomki, Debrecen, H-4001, Hungary -- Ertürk, S., Nigde Omer Halisdemir University, Science and Art Faculty, Department of Physics, Nigde, 51200, Turkey -- Gadea, A., Instituto de Física Corpuscular, CSIC-Universidad de Valencia, Valencia, E-46980, Spain -- Ghazi Moradi, F., Department of Physics, Royal Institute of Technology (KTH), Stockholm, SE-10691, Sweden -- Gottardo, A., Centre de Sciences Nucléaires et Sciences de la Matière, CNRS/IN2P3, Université Paris-Saclay, Orsay, 91405, France -- Hüyük, T., Instituto de Física Corpuscular, CSIC-Universidad de Valencia, Valencia, E-46980, Spain -- Ideguchi, E., Research Center for Nuclear Physics, Osaka University, Osaka, Japan -- Li, H., Department of Physics, Royal Institute of Technology (KTH), Stockholm, SE-10691, Sweden -- Michelagnoli, C., Grand Accélérateur National d’Ions Lourds (GANIL), CEA/DSM - CNRS/IN2P3, Bd Henri Becquerel, BP 55027, Caen Cedex 5, F-14076, France -- Modamio, V., Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, I-35020, Italy -- Nyberg, J., Department of Physics and Astronomy, Uppsala University, Uppsala, SE-75120, Sweden -- Palacz, M., Heavy Ion Laboratory, University of Warsaw, Pasteura 5A, Warsaw, PL 02-093, Poland -- Petrache, C.M., Centre de Sciences Nucléaires et Sciences de la Matière, CNRS/IN2P3, Université Paris-Saclay, Orsay, 91405, France -- Recchia, F., Dipartimento di Fisica e Astronomia, Università di Padova, Padova, Italy -- Sandzelius, M., University of Jyväskylä, Department of Physics, Jyväskylä, FI-40014, Finland -- Siciliano, M., Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, I-35020, Italy -- Timár, J., MTA Atomki, Debrecen, H-4001, Hungary -- Valiente-Dobón, J.J., Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, I-35020, Italy -- Xiao, Z.G., Department of Physics, Tsinghua University, Beijing, 100084, China, 0-Belirlenecek, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre 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), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Angular momentum, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Hadron, Elementary particle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Spectral line, 0-Belirlenecek, Baryon, Excited state, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon
Abstract

Lifetimes of high-spin states have been measured in the semi-magic (N= 50) nucleus 94Ru. Excited states in 94Ru were populated in the 58Ni(40Ca, 4p)94Ru* fusion-evaporation reaction at the Grand Accélérateur National d’Ions Lourds (GANIL) accelerator complex. DSAM lifetime analysis was performed on the Doppler broadened line shapes in energy spectra obtained from ?-rays emitted while the residual nuclei were slowing down in a thick 6mg/cm^2 metallic 58Ni target. In total eight excited-state lifetimes in the angular momentum range I= (13 - 20) ? have been measured, five of which were determined for the first time. The corresponding B(M1) and B(E2) reduced transition strengths are discussed within the framework of large-scale shell model calculations to study the contribution of different particle-hole configurations, in particular for analyzing contributions from core-excited configurations. © 2018, SIF, Springer-Verlag GmbH Germany, part of Springer Nature., National Brain Research Centre Vetenskapsrådet Göran Gustafssons Stiftelse för Naturvetenskaplig och Medicinsk Forskning Firat University Scientific Research Projects Management Unit Ministerio de Economía y Competitividad Science and Technology Facilities Council, We thank the operators of the GANIL cyclotrons for providing the beam, their cooperation and technical support. We would also like to thank the EXOGAM, DIAMANT and Neutron Wall Collaborations. This work was supported by the Swedish Research Council under Grant Nos. 621-2014-5558, 621-2012-3805, and 621-2013-4323 and the Göran Gustafsson foundation, the Scientific Research Projects Coordination Unit of Istanbul University Project No. 47886 and 48101, the UK STFC under grant number ST/L005727/1, the Spanish Ministerio de Economía y Competitividad under grant FPA2014-52823-C2-1-P and the program Severo Ochoa (SEV-2014-0398), the Polish National Research Centre contracts no. 2013/08/M/ST2 /00257 (LEA COPIGAL) and 2016/22/M/ST2/00269, the Scientific and Technological Council of Turkey (Proj. no. 114F473). BMN, IK, ZD and JT acknowledge the financial support of GINOP-2.3.3-15-2016-00034. IK was supported by National Research, Development and Innovation Office NK-FIH, contract number PD 124717. The computations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at PDC, KTH, Stockholm.

Published
2018

35. Digital pulse-timing technique for the neutron detector array NEDA

Author

V. Modamio, G. Jaworski, A. Triossi, Marek Moszynski, A. Gadea, T. Hüyük, S. Erturk, Johan Nyberg, Vicente González, Enrique Sanchis, J. J. Valiente-Dobón, A. Di Nitto, J. Kownacki, M. Palacz, J. Egea, J. Agramunt Ros, G. de Angelis, M. N. Erduran, R. Wadsworth, P. A. Söderström, 0-Belirlenecek, 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), Triossi, Andrea -- 0000-0001-5140-9154, Millan, Vicente Gonzalez -- 0000-0001-6014-2586, Jaworski, Grzegorz -- 0000-0003-2241-0329, Gadea, Andres -- 0000-0002-4233-1970, Di Nitto, Antonio -- 0000-0002-9319-366X, SANCHIS, ENRIQUE -- 0000-0002-9689-9131, Huyuk, Tayfun -- 0000-0003-0597-9767, Soderstrom, Par-Anders -- 0000-0002-9504-2814, de France, Gilles -- 0000-0002-7439-1759, [Modamio, V. -- Valiente-Dobon, J. J. -- Triossi, A. -- de Angelis, G.] Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy -- [Jaworski, G.] Warsaw Univ Technol, Fac Phys, PL-00662 Warsaw, Poland -- [Jaworski, G. -- Kownacki, J. -- Palacz, M.] Univ Warsaw, Heavy Ion Lab, PL-02093 Warsaw, Poland -- [Hueyuek, T. -- Egea, J. -- Agramunt Ros, J. -- Gadea, A.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46980 Valencia, Spain -- [Egea, J. -- Gonzalez, V. -- Sanchis, E.] Univ Valencia, Dept Elect Engn, E-46100 Burjassot, Spain -- [Di Nitto, A.] Johannes Gutenberg Univ Mainz, D-55099 Mainz, Germany -- [Soederstroem, P. -A.] RIKEN, Nishina Ctr, Wako, Saitama 3510198, Japan -- [de France, G.] CEA, GANIL, DSAM, F-14076 Caen, France -- [de France, G.] IN2P3, CNRS, F-14076 Caen, France -- [Erduran, M. N.] Istanbul Sabahattin Zaim Univ, Fac Engn & Nat Sci, TR-34303 Cerrahpasa, Turkey -- [Erturk, S.] Nigde Univ, Fen Edebiyat Falkultesi, Fiz Bolumu, TR-51240 Nigde, Turkey -- [Moszynski, M.] Natl Ctr Nucl Res, PL-05400 Otwock, Poland -- [Nyberg, J.] Uppsala Univ, Dept Phys & Astron, SE-75120 Uppsala, Sweden -- [Wadsworthm, R.] Univ York, Dept Phys, York YO1 5DD, N Yorkshire, England, Modamio, V., Valiente-Dobon, J. J., Jaworski, G., Huyuk, T., Triossi, A., Egea, J., Di Nitto, A., Soderstrom, P. -A., Agramunt Ros, J., De Angelis, G., De France, G., Erduran, M. N., Erturk, S., Gadea, A., Gonzalez, V., Kownacki, J., Moszynski, M., Nyberg, J., Palacz, M., Sanchis, E., and Wadsworth, R.

Subjects
Physics, Nuclear and High Energy Physics, Photomultiplier, Liquid scintillator, Physics::Instrumentation and Detectors, business.industry, Neutron detector, Detector, Constant fraction discriminator, NEDA, Zero crossing, Particle detector, Optics, Digital timing, Sampling (signal processing), BC501A, Scintillation counter, Neutron detection, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], business, Instrumentation, ComputingMilieux_MISCELLANEOUS
Abstract

WOS: 000348040900011, A new digital pulse-timing algorithm, to be used with the future neutron detector array NEDA, has been developed and tested. The time resolution of four 5 in diameter photomultiplier tubes (XP4512, R4144, R11833-100, and ET9390-kb), coupled to a cylindrical 5 in by 5 in BC501A liquict scintillator detector was measured by employing digital sampling electronics and a constant fraction discriminator (CFD) algorithm. The zero crossing of the CM algorithm was obtained with a cubic spline interpolation, which was continuous up to the second derivative. The performance of the algorithm was studied at sampling rates of 500 MS/s and 200 MS/s. The time resolution obtained with the digital electronics was compared to the values acquired with a standard analog CFD. The result of this comparison shows that the time resolution from the analog and the digital measurements at 500 MS/s and at 200 MS/s are within 15% for all the tested photomultiplier tubes. (C) 2014 Elsevier B.V. All rights reserved., Generalitat Valenciana, Spain [PROMETEO/2010/101, PROMETEO/2014/019]; MINECO, Spain [AIC-D-2011-0746, FPA2011-29854, FPA2012-33560]; STFC, UK; Swedish Research Council; Science and Technology Facilities Council [ST/L005727/1, ST/L005735/1, ST/J000124/1], Work partially supported by the Generalitat Valenciana, Spain, under grant PROMETEO/2010/101 and PROMETEO/2014/019, by MINECO, Spain, under grants AIC-D-2011-0746, FPA2011-29854 and FPA2012-33560, by the STFC, UK and by the Swedish Research Council.

Published
2015

36. Neutron effective single-particle energies above Ni78 : A hint from lifetime measurements in the N=51 isotones Se85 and Kr87

Author

S. Leoni, R. Menegazzo, C. Fransen, A. Gottardo, V. Vandone, E. Fioretto, L. Corradi, A. Dewald, Kamila Sieja, E. Sahin, L. Sengele, G. Duchêne, A. M. Stefanini, A. Bracco, G. Montagnoli, D. Mengoni, K. Kolos, E. Ellinger, M. Hackstein, S. Lunardi, S. Franchoo, D. R. Napoli, D. Montanari, F. Recchia, J. J. Valiente-Dobón, A. I. Morales, S. Bottoni, S. M. Lenzi, A. Goasduff, D. Verney, G. de Angelis, F. Didierjean, C. Michelagnoli, L. Grocutt, F. C. L. Crespi, D. Bazzacco, J. F. Smith, J. Litzinger, Suzana Szilner, F. Scarlassara, Megumi Niikura, R. Lozeva, O. Möller, E. Farnea, T. Mijatović, V. Modamio, C. A. Ur, Sibel Zehra Aydin, and F. Ibrahim

Subjects
Physics, 010308 nuclear & particles physics, Nuclear structure, 01 natural sciences, 7. Clean energy, Particle identification, Recoil, Atomic orbital, 0103 physical sciences, Particle, Neutron, AGATA, Atomic physics, 010306 general physics, Energy (signal processing)
Abstract

Background: While the $N=50$ shell-gap evolution towards $^{78}\mathrm{Ni}$ is presently in the focus of nuclear structure research, experimental information on the neutron effective single-particle energy sequence above the $^{78}\mathrm{Ni}$ core remain scarce. Direct nucleon-exchange reactions are indeed difficult with presently available post-accelerated radioactive-ion beams (especially for high orbital-momentum orbitals) in this exotic region.Purpose: In this study we probe the evolution of the $\ensuremath{\nu}1{g}_{7/2}$ effective single-particle energy which is a key to understanding the possible evolution of the spin-orbit splitting due to the proton-neutron interaction in the $^{78}\mathrm{Ni}$ region. To achieve this goal, a method based on lifetime measurements is used for the first time. The obtained lifetimes of the $7/{2}_{1}^{+}$ states in $^{87}\mathrm{Kr}$ and $^{85}\mathrm{Se}$ are used to investigate the $\ensuremath{\nu}1{g}_{7/2}$ evolution.Method: Yrast and near-yrast states in the light $N=51$ isotones $^{85}\mathrm{Se}$ and $^{87}\mathrm{Kr}$ were populated via multinucleon transfer reactions, using a $^{82}\mathrm{Se}$ beam and a $^{238}\mathrm{U}$ target at the LNL tandem-ALPI facility. The prompt $\ensuremath{\gamma}$ rays were detected by the AGATA Demonstrator and particle identification was performed using the PRISMA spectrometer. Lifetime measurements were performed by using the Cologne plunger device for deep inelastic reactions and the Recoil Distance Doppler Shift technique.Results: We obtain ${\ensuremath{\tau}}_{(7/{2}_{1}^{+})}=0.{4}_{\ensuremath{-}0.4}^{+1.6}$ ps for $^{87}\mathrm{Kr}$. In the case of $^{85}\mathrm{Se}$ an upper limit of 3(2) ps is obtained for the ${\ensuremath{\tau}}_{7/{2}_{1}^{+}}$ value.Conclusion: For $^{87}\mathrm{Kr}$, the measured $(7/{2}_{1}^{+})$ lifetime is consistent with a core-coupled ${2}^{+}\ensuremath{\bigotimes}\ensuremath{\nu}2{d}_{5/2}$ configuration for this state. This result is consistent with that obtained by direct reaction, which validates our method. For $^{85}\mathrm{Se}$, the measured $7/{2}_{1}^{+}$ lifetime limit indicates a very small contribution of the $\ensuremath{\nu}1{g}_{7/2}$ configuration to the wave function of this state.

Published
2017

37. Determination of lifetimes of nuclear excited states using the Recoil Distance Doppler Shift Method in combination with magnetic spectrometers

Author

J. J. Valiente-Dobón, O. Möller, D. Mengoni, A. Dewald, Begoña Quintana, V. Modamio, A. Gadea, Maria Doncel, and Norbert Pietralla

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, 010308 nuclear & particles physics, Hadron, 01 natural sciences, Ion, symbols.namesake, Recoil, Excited state, 0103 physical sciences, symbols, Nuclear fusion, AGATA, Atomic physics, Nuclear Experiment, 010306 general physics, Doppler effect
Abstract

The current work presents the determination of lifetimes of nuclear excited states using the Recoil Distance Doppler Shift Method, in combination with spectrometers for ion identification, normalizing the intensity of the peaks by the ions detected in the spectrometer as a valid technique that produces results comparable to the ones obtained by the conventional shifted-to-unsifted peak ratio method. The technique has been validated using data measured with the $ \gamma$ -ray array AGATA, the PRISMA spectrometer and the Cologne plunger setup. In this paper a test performed with the AGATA-PRISMA setup at LNL and the advantages of this new approach with respect to the conventional Recoil Distance Doppler Shift Method are discussed.

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. Experimental study of the isovector giant dipole resonance in Zr80 and Rb81

Author

C. A. Ur, R. Nicolini, D. Bazzacco, F. Recchia, M. Kmiecik, A. Bracco, A. Giaz, D. Mengoni, S. Brambilla, G. Benzoni, A. Gottardo, S. Bottoni, N. Blasi, E. Sahin, S. Ceruti, S. Leoni, Stefano Riboldi, V. Modamio, R. Avigo, G. Bocchi, D. R. Napoli, D. Montanari, B. Million, F. C. L. Crespi, A. I. Morales, Oliver Wieland, E. Farnea, C. Michelagnoli, M. Ciemala, J. J. Valiente-Dobón, Luna Pellegri, B. Wasilewska, M. Zieblinski, F. Camera, A. Maj, and A. Mentana

Subjects
Physics, Isovector, 010308 nuclear & particles physics, Nuclear Theory, Resonance, 01 natural sciences, Dipole, Nuclear magnetic resonance, 0103 physical sciences, Coulomb, Nuclear fusion, AGATA, Atomic physics, Nuclear Experiment, 010306 general physics, Energy (signal processing), Excitation
Abstract

The isovector giant dipole resonance (IVGDR) $\ensuremath{\gamma}$ decay was measured in the compound nuclei $^{80}\mathrm{Zr}$ and $^{81}\mathrm{Rb}$ at an excitation energy of ${E}^{*}=54$ MeV. The fusion reaction $^{40}\mathrm{Ca}+^{40}\mathrm{Ca}$ at ${E}_{\mathrm{beam}}=136$ MeV was used to form the compound nucleus $^{80}\mathrm{Zr}$, while the reaction $^{37}\mathrm{Cl}+^{44}\mathrm{Ca}$ at ${E}_{\mathrm{beam}}=95$ MeV was used to form the compound nucleus $^{81}\mathrm{Rb}$ at the same excitation energy. The IVGDR parameters extracted from the analysis were compared with the ones found at higher excitation energy (${E}^{*}=83$ MeV). The comparison allows one to observe two different nuclear mechanisms: (i) the IVGDR intrinsic width remains constant with the excitation energy in the nucleus $^{81}\mathrm{Rb}$; (ii) the isospin-violating spreading width (i.e., Coulomb spreading width) remains constant with the excitation energy in the nucleus $^{80}\mathrm{Zr}$. The experimental setup used for the $\ensuremath{\gamma}$-ray detection was composed by the AGATA demonstrator array coupled to the large-volume ${\mathrm{LaBr}}_{3}$:Ce detectors of the ${\mathrm{HECTOR}}^{+}$ array.

Published
2017

40. Isospin Symmetry Breaking in Mirror Nuclei $^{23}$Mg$-$$^{23}$Na

Author

A. Boso, S.M. Lenzi, F. Recchia, J. Bonnard, S. Aydin, M.A. Bentley, B. Cederwall, E. Clement, G. De France, A. Di Nitto, A. Dijon, M. Doncel, F. Ghazi-Moradi, A. Gottardo, T. Henry, T. Hüyük, G. Jaworski, P.R. John, K. Juhász, I. Kuti, B. Melon, D. Mengoni, C. Michelagnoli, V. Modamio, D.R. Napoli, B.M. Nyakó, J. Nyberg, M. Palacz, J.J. Valiente-Dobón, Dipartimento di Fisica [Padova], Universita degli Studi di Padova, Aksaray University, 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), Boso, A., Lenzi, S. M., Recchia, F., Bonnard, J., Aydin, S., Bentley, M. A., Cederwall, B., Clement, E., De France, G., Di Nitto, A., Dijon, A., Doncel, M., Ghazi-Moradi, F., Gottardo, A., Henry, T., Huyu, T., Jaworski, G., John, P. R., Juhasz, K., Kuti, I., Melon, B., Mengoni, D., Michelagnoli, C., Modamio, V., Napoli, D. R., Nyako, B. M., Nyberg, J., Palacz, M., Valiente-Dobo, J. J., Sabire Yazıcı Fen Edebiyat Fakültesi, Di Nitto, Antonio -- 0000-0002-9319-366X, Cederwall, Bo -- 0000-0003-1771-2656, Huyuk, Tayfun -- 0000-0003-0597-9767, John, Philipp Rudolf -- 0000-0003-1994-7248, de France, Gilles -- 0000-0002-7439-1759, BOSO, ALBERTO -- 0000-0001-9670-8123, Clement, Emmanuel -- 0000-0003-1887-717X, GOTTARDO, Andrea -- 0000-0002-0390-5767, Napoli, Daniel R. -- 0000-0002-8154-6958, Università degli Studi di Padova = University of Padua (Unipd), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Particle physics, Rho meson, Statistics::Applications, Weak isospin, 010308 nuclear & particles physics, Spontaneous symmetry breaking, Physics::Medical Physics, Nuclear Theory, Nuclear structure, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Quantitative Biology::Cell Behavior, 13. Climate action, Isospin, 0103 physical sciences, Symmetry breaking, Mirror nuclei, 010306 general physics, Chiral symmetry breaking, Nuclear Experiment
Abstract

Zakopane Conference on Nuclear Physics - Extremes of the Nuclear Landscape -- AUG 28-SEP 04, 2016 -- Zakopane, POLAND, WOS: 000398717500011, Mirror energy differences (MED) are a direct consequence of isospin symmetry breaking. Moreover, the study of MED has proved to give valuable information of several nuclear structure properties. We present the results of an experiment performed in GANIL to study the MED in mirror nuclei Mg-23-Na-23 up to high spin. The experimental values are compared with state-of-the-art shell model calculations. This permits to enlighten several nuclear structure properties, such as the way in which the nucleons alignment proceeds, the radius variation with J, the role of the spin-orbit interaction and the importance of isospin symmetry breaking terms of nuclear origin.

Published
2016

41. Lifetime Measurements with the Doppler Shift Attenuation Method Using a Thick Homogeneous Production Target — Verification of the Method

Author

A. Ertoprak, B. Cederwall, U. Jakobsson, B.M. Nyakó, J. Nyberg, P. Davies, M. Doncel, G. De France, I. Kuti, D.R. Napoli, R. Wadsworth, S.S. Ghugre, R. Raut, B. Akkus, H. Al-Azri, A. Algora, G. de Angelis, A. Atac, T. Bäck, A. Boso, E. Clément, D.M. Debenham, Zs. Dombrádi, S. Erturk, A. Gadea, F. Ghazi Moradi, A. Gottardo, T. Huyuk, E. Ideguchi, G. Jaworski, H. Li, C. Michelagnoli, V. Modamio, M. Palacz, C.M. Petrache, F. Recchia, M. Sandzelius, M. Siciliano, J. Timár, J.J. Valiente-Dobón, Z.G. Xiao, 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), 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, ta114, Doppler Shift Attenuation Method, 010308 nuclear & particles physics, business.industry, Attenuation, lifetime measurement, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, symbols.namesake, Optics, Homogeneous, 0103 physical sciences, symbols, 010306 general physics, business, Doppler effect, FOIL method
Abstract

International audience; Doppler Shift Attenuation Method (DSAM) analysis of excited-state lifetimes normally employs thin production targets mounted on a thick stopper foil (“backing”) serving to slow down and stop the recoiling nuclei of interest in a well-defined manner. Use of a thick, homogeneous production target leads to a more complex analysis as it results in a substantial decrease in the energy of the incident projectile which traverses the target with an associated change in the production cross section of the residues as a function of penetration depth. Here, a DSAM lifetime analysis using a thick homogeneous target has been verified using the Doppler broadened lineshapes of γ rays following the decay of highly excited states in the semi-magic (N = 50) nucleus 94Ru. Lifetimes of excited states in the 94Ru nucleus have been obtained using a modified version of the LINESHAPE package from the Doppler broadened lineshapes resulting from the emission of the γ rays, while the residual nuclei were slowing down in the thick (6 mg/cm2) metallic 58Ni target. The results have been validated by comparison with a previous measurement using a different (RDDS) technique.

Published
2016

42. Quadrupole Transition Strength in the Ni74 Nucleus and Core Polarization Effects in the Neutron-Rich Ni Isotopes

Author

T. Marchi, G. de Angelis, J. .J. Valiente Dobón, V. .M. Bader, T. Baugher, D. Bazin, J. Berryman, A. Bonaccorso, R. Clark, L. Coraggio, H. .L. Crawford, M. Doncel, E. Farnea, A. Gade, A. Gadea, A. Gargano, T. Glasmacher, A. Gottardo, F. Gramegna, P. .R. John, R. Kumar, S. .M. Lenzi, S. Lunardi, S. McDaniel, C. Michelagnoli, D. Mengoni, V. Modamio, D. .R. Napoli, B. Quintana, A. Ratkiewicz, F. Recchia, E. Sahin, R. Stroberg, D. Weisshaar, K. Wimmer, R. Winkler, ITACO, Nunzio, T., Marchi, G., de Angeli, Valiente Dobón, J. . J., Bader, V. . M., T., Baugher, D., Bazin, J., Berryman, A., Bonaccorso, R., Clark, L., Coraggio, Crawford, H. . L., M., Doncel, E., Farnea, A., Gade, A., Gadea, A., Gargano, T., Glasmacher, A., Gottardo, F., Gramegna, Itaco, Nunzio, John, P. . R., R., Kumar, Lenzi, S. . M., S., Lunardi, S., Mcdaniel, C., Michelagnoli, D., Mengoni, V., Modamio, Napoli, D. . R., B., Quintana, A., Ratkiewicz, F., Recchia, E., Sahin, R., Stroberg, D., Weisshaar, K., Wimmer, R., Winkler, Marchi, T., de Angelis, G., Baugher, T., Bazin, D., Berryman, J., Bonaccorso, A., Clark, R., Coraggio, L., Doncel, M., Farnea, E., Gade, A., Gadea, A., Gargano, A., Glasmacher, T., Gottardo, A., Gramegna, F., Kumar, R., Lunardi, S., Mcdaniel, S., Michelagnoli, C., Mengoni, D., Modamio, V., Quintana, B., Ratkiewicz, A., Recchia, F., Sahin, E., Stroberg, R., Weisshaar, D., Wimmer, K., and Winkler, R.

Abstract

The reduced transition probability B(E2;0(+) -> 2(+)) has been measured for the neutron-rich nucleus Ni-74 in an intermediate energy Coulomb excitation experiment performed at the National Superconducting Cyclotron Laboratory at Michigan State University. The obtained B(E2;0(+) -> 2(+)) = 642(-226)(+216) e(2) fm(4) value defines a trend which is unexpectedly small if referred to Ni-70 and to a previous indirect determination of the transition strength in Ni-74. This indicates a reduced polarization of the Z = 28 core by the valence neutrons. Calculations in the pfgd model space reproduce well the experimental result indicating that the B(E2) strength predominantly corresponds to neutron excitations. The ratio of the neutron and proton multipole matrix elements supports such an interpretation.

Published
2014

43. Low-lying excitations in Ni 72

Author

Giuseppe Lorusso, T. Isobe, Rin Yokoyama, S. Ceruti, Zhengyu Xu, R. Avigo, H. Shaffner, Ryo Taniuchi, D. Mengoni, J. J. Valiente-Dobón, Stephen Rice, N. Kurz, Zena Patel, K. Matsui, R. Orlandi, Shunji Nishimura, István Kuti, Toshiyuki Sumikama, Megumi Niikura, A. Bracco, Y. F. Fang, E. Sahin, Hirofumi Watanabe, H. Baba, M. Yalcinkaya, G. de Angelis, Ayumi Yagi, D. R. Napoli, Zs. Vajta, P. A. Söderström, Jan Taprogge, Zs. Dombrádi, G. Benzoni, P. Doornenbal, I. Kojouharov, Oliver Wieland, Hiroyoshi Sakurai, L. Sinclair, R. Daido, A. I. Morales, Satoru Momiyama, F. L. Bello Garrote, A. Gottardo, F. Camera, B. Melon, V. Modamio-Hoyborg, F. Browne, M. C. Delattre, Tadashi Miyazaki, Dóra Sohler, Jin Wu, N. Blasi, F. C. L. Crespi, Ministero dell'Istruzione, dell'Università e della Ricerca, National Research Foundation of Korea, Ministry of Science, ICT and Future Planning (South Korea), RIKEN Nishina Center for Accelerator-Based Science, Ministerio de Ciencia e Innovación (España), Hungarian Scientific Research Fund, Japan Society for the Promotion of Science, European Commission, Institut de Physique Nucléaire d'Orsay (IPNO), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Physics, SIMPLE (dark matter experiment), Nuclear and High Energy Physics, Isotope, 010308 nuclear & particles physics, Fission, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, Excited state, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics
Abstract

A. I. Morales et al.; 14 págs.; 9 figs.; 3 tabs., Low-lying excited states in Ni72 have been investigated in an in-flight fission experiment at the RIBF facility of the RIKEN Nishina Center. The combination of the state-of-the-art BigRIPS and EURICA setups has allowed for a very accurate study of the β decay from Co72 to Ni72, and has provided first experimental information on the decay sequence Fe72→Co72→Ni72 and on the delayed neutron-emission branch Co73→Ni72. Accordingly, we report nearly 60 previously unobserved γ transitions which deexcite 21 new levels in Ni72. Evidence for the location of the so-sought-after (42+),(62+), and (81+) seniority states is provided. As well, the existence of a low-spin β-decaying isomer in odd-odd neutron-rich Co isotopes is confirmed for mass A=72. The new experimental information is compared to simple shell-model calculations including only neutron excitations across the fpg shells. It is shown that, in general, the calculations reproduce well the observed states. ©2016 American Physical Society, The excellent work of the RIKEN accelerator staff for providing a stable and high-intensity 238U beam is acknowledged. Part of he WAS3ABi was supported by the Rare Isotope Science Project, which is funded by the Ministry of Science, ICT and Future Planning (MSIP) and National Research Foundation (NRF) of Korea. This work is cofinanced by the European Union and the European Social Fund. Support from italian Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale (PRIN) Grant No. 2001024324_01302, the NuPNET-ERANET within the NuPNET GANAS project under Grant Agreement No. 202914, and the European Union within the 7th Framework Program FP7/2007-2013 under Grant Agreement No. 262010 ENSAR-INDESYS is acknowledged. This work was also financed by the Spanish Ministerio de Ciencia e Innovación under ContractsNo. FPA2009-13377-C02 and No. FPA2011-29854-C04, the Hungarian Research Fund OTKA Contract No. K100835 and No. K106035, the European Commission through the Marie Curie Actions Contract No. PIEFGA-2001-30096, and by the Japanese JSPS KAKENHI Grants No. 24740188 and No. 25247045

Published
2016

44. Structure of the As, Ge, Ga nuclei

Author

D. Bazzacco, D. Mengoni, M. D. Salsac, A. Khouaja, S. M. Lenzi, E. Sahin, A. F. Lisetskiy, Kenia Teodoro Wiedemann, R. P. Singh, D. Curien, J. J. Valiente-Dobón, E. Fioretto, P. Mason, U. Datta Pramanik, A. Gottardo, J. Ollier, I. Stefan, R. Chapman, L. Corradi, F. Recchia, S. Courtin, R. Orlandi, G. Benzoni, B.J.P. Gall, S. Aydin, J. F. Smith, T. Byrski, K. Zuber, R. Moro, S. Erturk, Igor T. Čeliković, Predrag Ujić, Alejandro Algora, A. M. Stefanini, E. Farnea, M. Labiche, Dieter Ackermann, D. Verney, S. Leoni, G. Montagnoli, R. Silvestri, D. Lebhertz, P. T. Wady, F. Haas, G. Pollarolo, M. Yalcinkaya, A. Gadea, B. Mouginot, F. Ibrahim, O. Dorvaux, F. Azaiez, T. Faul, J. Robin, C. Michelagnoli, S. Franchoo, D. A. Torres, S. Szilner, David O'Donnell, C. A. Ur, Fernando Scarlassara, M. Trotta, A. Kusoglu, M. N. Erduran, B. Guiot, V. Modamio, K. Subotic, G. Duchêne, S. Lunardi, D. Montanari, G. de Angelis, F. Didierjean, M. Bostan, D. Tonev, D. R. Napoli, Elif Ince, J. R. B. Oliveira, and G. La Rana

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Band gap, Nuclear Theory, SHELL model, Shell (structure), Structure (category theory), 01 natural sciences, Stability (probability), Coincidence, 0103 physical sciences, Order (group theory), Atomic physics, 010306 general physics
Abstract

The level structures of the N = 50 83As, 82Ge, and 81Ga isotones have been investigated by means of multi-nucleon transfer reactions. A first experiment was performed with the CLARA–PRISMA setup to identify these nuclei. A second experiment was carried out with the GASP array in order to deduce the γ-ray coincidence information. The results obtained on the high-spin states of such nuclei are used to test the stability of the N = 50 shell closure in the region of 78Ni ( Z = 28 ). The comparison of the experimental level schemes with the shell-model calculations yields an N = 50 energy gap value of 4.7(3) MeV at Z = 28 . This value, in a good agreement with the prediction of the finite-range liquid-drop model as well as with the recent large-scale shell model calculations, does not support a weakening of the N = 50 shell gap down to Z = 28 .

Published
2012

45. Transition probabilities in neutron-richSe84,86

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, SHELL model, symbols.namesake, Recoil, Excited state, Quadrupole, symbols, Physics::Accelerator Physics, Neutron, Physics::Atomic Physics, Atomic physics, Nuclear Experiment, Doppler effect
Abstract

Reduced quadrupole transition probabilities for low-lying transitions in neutron-rich Se-84,Se-86 are investigated with a recoil distance Doppler shift (RDDS) experiment. The experiment was perform ...

Published
2015

46. Decay properties of 68,69,70Mn: Probing collectivity up to N=44 in Fe isotopic chain

Author

Satoru Momiyama, F. Browne, Toshiyuki Sumikama, G. Benzoni, Tadaaki Isobe, H. Baba, M.-C. Delattre, V. Modamio-Hoybjor, A. Bracco, Ryo Taniuchi, R. Daido, Jan Taprogge, D. Mengoni, Y. F. Fang, J. J. Valiente-Dobón, L. Sinclair, Tadashi Miyazaki, Shunji Nishimura, Jin Wu, Dóra Sohler, Megumi Niikura, S. Ceruti, Simon Rice, L. Coraggio, István Kuti, Zs. Vajta, Pieter Doornenbal, Giuseppe Lorusso, Hiroshi Watanabe, D. R. Napoli, Hiroyoshi Sakurai, Zhengyu Xu, R. Avigo, B. Melon, F. C. L. Crespi, A. Gargano, F. L. Bello Garrote, F. Camera, K. Matsui, N. Blasi, Rin Yokoyama, Oliver Wieland, G. de Angelis, Zena Patel, A. I. Morales, E. Sahin, Nunzio Itaco, P. A. Söderström, M. Yalcinkaya, R. Orlandi, A. Gottardo, Zsolt Dombrádi, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Hungarian Scientific Research Fund, Ministerio de Ciencia e Innovación (España), European Commission, and Japan Society for the Promotion of Science

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, Isotope, 010308 nuclear & particles physics, Fission, Neutron emission, Nuclear Theory, Fizikai tudományok, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, lcsh:QC1-999, 3. Good health, Atomic orbital, Természettudományok, Excited state, 0103 physical sciences, Quadrupole, Atomic physics, 010306 general physics, Nucleon, Nuclear Experiment, lcsh:Physics
Abstract

6 pags.; 4 figs.; This is an open access article under the CC BY license. Funded by SCOAP, © 2015 The Authors. The β decays Mn68→Fe68, Mn69→Fe69 and Mn70→Fe70 have been measured at the RIBF facility at RIKEN using the EURICA γ spectrometer combined with an active stopper consisting of a stack of Si detectors. The nuclei were produced as fission fragments from a beam of 238U at a bombarding energy of 345 MeV/nucleon impinging on a Be target and selected using the BigRIPS separator. Half-lives and β-delayed neutron emission probabilities have been extracted for these decays, together with first experimental information on excited states populated in 69,70Fe. The data indicate a continuously increasing deformation for Fe isotopes up to A=70. This is interpreted, as for Cr isotopes, in terms of the interplay between the quadrupole correlations of the ν1d5/2 and ν0g9/2 orbitals and the monopole component of the π0f7/2-ν0f5/2 interaction., The project is co-financed by the European Union and the European Social Fund. This work was supported by NuPNET-ERANET within the NuPNET GANAS project, under grant agreement No. 202914 and from the European Union, within the 7th Framework Program FP7/2007-2013, under grant agreement No. 262010 ENSAR-INDESYS. This work was also supported by Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale (PRIN) number 2001024324_01302. We here acknowledge support from the Spanish Ministerio de Ciencia e Innovación under Contracts No. FPA2009-13377-C02 and No. FPA2011-29854-C04, the Hungarian Research Fund OTKA contract numbers K100835 and NN104543, the European Commission through the Marie Curie Actions Contract No. PIEFGA-2001-30096 and by Japanese JSPS KAKENHI Grants No. 24740188 and No. 25247045.

Published
2015

47. Isospin Mixing inZr80: From Finite to Zero Temperature

Author

S. Brambilla, S. Leoni, D. Bazzacco, P. Désesquelles, Stefano Riboldi, D. S. Judson, P. Reiter, O. Stezowski, G. Benzoni, Herbert Hess, R. Menegazzo, R. Avigo, F. C. L. Crespi, M. Ciemala, F. Camera, E. Farnea, M. Kmiecik, Andreas Görgen, G. Bocchi, J. J. Valiente-Dobón, F. Recchia, R. Nicolini, D. Montanari, P. A. Söderström, B. Birkenbach, J. Eberth, M. Zieblinski, V. Modamio, S. Myalski, Luna Pellegri, B. Million, A. Mentana, A. Jungclaus, S. Bottoni, C. A. Ur, W. Korten, D. R. Napoli, Ch. Theisen, N. Blasi, S. Ceruti, A. Bracco, A. Pullia, A. Giaz, A. Maj, A. Gottardo, O. Wieland, D. Mengoni, E. Sahin, M.D. Salsac, Begoña Quintana, D. Rosso, A. I. Morales, and C. Michelagnoli

Subjects
Physics, 010308 nuclear & particles physics, Nuclear Theory, Gamma ray, General Physics and Astronomy, Resonance, 7. Clean energy, 01 natural sciences, Nuclear physics, Dipole, Isospin, 0103 physical sciences, AGATA, Atomic physics, Nuclear Experiment, 010306 general physics, Mixing (physics), Excitation, Fermi Gamma-ray Space Telescope
Abstract

The isospin mixing was deduced in the compound nucleus Zr-80 at an excitation energy of E* = 54 MeV from the gamma decay of the giant dipole resonance. The reaction Ca-40 + Ca-40 at E-beam = 136 MeV was used to form the compound nucleus in the isospin I = 0 channel, while the reaction Cl-37 + Ca-44 at E-beam = 95 MeV was used as the reference reaction. The. rays were detected with the AGATA demonstrator array coupled with LaBr3:Ce detectors. The temperature dependence of the isospin mixing was obtained and the zero-temperature value deduced. The isospin-symmetry-breaking correction delta(C) used for the Fermi superallowed transitions was extracted and found to be consistent with beta-decay data.

Published
2015

48. Population of the2ms+mixed-symmetry state ofBa140with theα-transfer reaction

Author

A. Gadea, W. Korten, D. Mengoni, P. A. Söderström, S. Lunardi, C. Michelagnoli, G. de Angelis, A. Goergen, V. Modamio, Hans-Jurgen E. Hess, D. Bazzacco, S. M. Lenzi, A. Pullia, J. Leske, J. Eberth, D. R. Napoli, M. Reese, F. C. L. Crespi, R. Menegazzo, C. A. Ur, P. Reiter, E. Farnea, Ch. Theisen, J. Jolie, B. Birkenbach, A. Bracco, P. Désesquelles, P. R. John, C. Bauer, J. J. Valiente-Dobón, J. Grebosz, A. Gottardo, A. Jungclaus, M. D. Salsac, Begoña Quintana, Norbert Pietralla, D. Rosso, C. Stahl, O. Stezowski, E. Sahin, and F. Recchia

Subjects
Physics, Nuclear and High Energy Physics, education.field_of_study, Isovector, Proton, 010308 nuclear & particles physics, Population, State (functional analysis), 01 natural sciences, Inelastic neutron scattering, 0103 physical sciences, Atomic nucleus, Interacting boson model, Atomic physics, 010306 general physics, Spectroscopy, education
Abstract

Background: Identification of proton-neutron mixed-symmetric one-quadrupole phonon excitations (the 2(ms)(+) states) of atomic nuclei provides information on the isovector part of the residual nucleon-nucleon interaction. It was predicted that the 2(ms)(+) state of particular nuclei close to the U(5) limit of the interacting boson model, in particular Ba-140, should be considerably populated by alpha-transfer reactions [C. E. Alonso et al., Phys. Rev. C 78, 017301 (2008)]. Purpose: We aim at the identification of the 2(ms)(+) mixed-symmetry state (MSS) of radioactive Ba-140 and investigate its population by the alpha-transfer reaction as a suitable tool to selectively populate MSSs and as a potential new signature for its mixed-symmetric character. Method: A gamma-ray spectroscopy experiment was performed in inverse kinematics in order to populate the 2(ms)(+) state of Ba-140 by alpha-transfer from a C-nat target on Xe-136 beam ions. The population of the candidate for the 2(ms)(+) state of Ba-140 was measured relative to the population of the 2(1)(+) state. Results: The candidate for the 2(ms)(+) state of Ba-140 was populated by a transfer three times weaker than predicted. Another 2(+) state that can be ruled out as the MSS was in turn as strongly populated by the a transfer as predicted for the MSS. Conclusions: The relative population of 2(+) states by alpha-transfer cannot serve as a new signature for MSSs, since other 2(+) states are also strongly populated. Nevertheless, the substantial population of the MSS candidate of Ba-140 by alpha transfer qualifies this type of reaction as suitable tool to excite MSSs and study their electromagnetic decay properties.

Published
2015

49. Reduced transition strengths of low-lying yrast states in chromium isotopes in the vicinity of N = 40

Author

T. Marchi, H. Iwasaki, F. Recchia, A. Gottardo, Alfred Dewald, A. Lemasson, V. Modamio, T.R. Baugher, Thomas Baumann, V. M. Bader, D. Weisshaar, S. M. Lenzi, C. Morse, C. Fransen, Alexandra Gade, J. Litzinger, R. Wadsworth, Dominique Bazin, K. Whitmore, J. S. Berryman, M. Albers, M. Hackstein, J. Jolie, Thomas Braunroth, A. J. Nichols, T. N. Ginter, D. R. Napoli, S. Lunardi, Kathrin Wimmer, S. R. Stroberg, 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), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Isotope, Yrast, Nuclear Theory, Nuclear structure, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, Recoil, Excited state, Quadrupole, Quasiparticle, Atomic physics, Nuclear Experiment, Excitation, ComputingMilieux_MISCELLANEOUS
Abstract

Background: In neutron-rich nuclei around $N=40$ rapid changes in nuclear structure can be observed. While $^{68}\mathrm{Ni}$ exhibits signatures of a doubly magic nucleus, experimental data along the isotopic chains in even more exotic Fe and Cr isotopes---such as excitation energies and transition strengths---suggest a sudden rise in collectivity toward $N=40$.Purpose: Reduced quadrupole transition strengths for low-lying transitions in neutron-rich $^{58,60,62}\mathrm{Cr}$ are investigated. This gives quantitative new insights into the evolution of quadrupole collectivity in the neutron-rich region close to $N=40$.Method: The recoil distance Doppler-shift (RDDS) technique was applied to measure lifetimes of low-lying states in $^{58,60,62}\mathrm{Cr}$. The experiment was carried out at the National Superconducting Cyclotron Laboratory (NSCL) with the SeGA array in a plunger configuration coupled to the S800 magnetic spectrograph. The states of interest were populated by means of one-proton knockout reactions.Results: Data reveal a rapid increase in quadrupole collectivity for $^{58,60,62}\mathrm{Cr}$ toward $N=40$ and point to stronger quadrupole deformations compared to neighboring Fe isotopes. The experimental $B(E2$) values are reproduced well with state-of-the-art shell-model calculations using the LNPS effective interaction. A consideration of intrinsic quadrupole moments and ${\mathrm{B}}_{42}$ ratios suggest an evolution toward a rotational nature of the collective structures in $^{60,62}\mathrm{Cr}$. Compared to $^{58}\mathrm{Cr}$, experimental ${\mathrm{B}}_{42}$ and ${\mathrm{B}}_{62}$ values for $^{60}\mathrm{Cr}$ are in better agreement with the $E(5)$ limit.Conclusion: Our results indicate that collective excitations in neutron-rich Cr isotopes saturate at $N=38$, which is in agreement with theoretical predictions. More detailed experimental data of excited structures and interband transitions are needed for a comprehensive understanding of quadrupole collectivity close to $N=40$. This calls for additional measurements in neutron-rich Cr and neighboring Ti and Fe nuclei.

Published
2015

50. β-Decay Measurements in the Vicinity of 78Ni with the EURICA Setup

Author

K. Matsui, Rin Yokoyama, Shin-Ichiro Nishimura, Hiroshi Watanabe, F. L. Bello Garrote, Ryo Taniuchi, P. A. Söderström, G. de Angelis, Y. D. Fang, T. Miyazaki, M. C. Delattre, E. Sahin, A. Gottardo, Laura C. Sinclair, Jinguang Wu, F. C. L. Crespi, Zs. Vajta, Megumi Niikura, Hiroyoshi Sakurai, Z. Patel, F. Browne, B. Melon, Satoru Momiyama, P. Doornenbal, V. Modamio-Hoybjor, O. Wieland, Zs. Dombrádi, R. Daido, T. Isobe, Stephen Rice, A. I. Morales, István Kuti, D. Mengoni, Ziye Xu, S. Ceruti, M. Yalcinkaya, R. Orlandi, Ayumi Yagi, J. J. Valiente-Dobón, D. R. Napoli, D. Sohler, Jan Taprogge, H. Baba, A. Bracco, Toshiyuki Sumikama, G. Benzoni, Giuseppe Lorusso, R. Avigo, and N. Blasi

Subjects
Physics
Published
2015

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