Suchergebnisse

LEMASSON, Antoine/0000-0002-9434-8520; Jaworski, Grzegorz/0000-0003-2241-0329; GOASDUFF, Alain/0000-0003-3453-3297; Georgiev, Georgi/0000-0003-1467-1764; SAYGI, BAHADIR/0000-0001-5406-506X; Maj, Adam/0000-0002-2873-7077; benzoni, giovanna/0000-0002-7938-0338; Siciliano, Marco/0000-0002-4598-0298; Leoni, Silvia/0000-0002-3691-0749; Nowacki, Frederic/0000-0002-7854-8717 ; WOS: 000571760900006 ; The lifetimes of the low-lying excited states 2(+) and 4(+) have been directly measured in the neutron-deficient Sn-106,Sn-108 isotopes. the nuclei were populated via a deep-inelastic reaction and the lifetime measurement was performed employing a differential plunger device. the emitted gamma rays were detected by the AGATA array, while the reaction products were uniquely identified by the VAMOS++ magnetic spectrometer. Large-Scale Shell-Model calculations with realistic forces indicate that, independently of the pairing content of the interaction, the quadrupole force is dominant in the B(E2; 2(1)(+) -> 0(g.s)(+)) values and it describes well the experimental pattern for Sn104-114 ; the B(E2;(+)(4) -> 2(1)(+)) values, measured here for the first time, depend critically on a delicate pairing-quadrupole balance, disclosed by the very precise results in Sn-108. (C) 2020 the Authors. Published by Elsevier B.V. ; European Union's Seventh Framework Programme for Research and Technological DevelopmentEuropean Union (EU) [262010]; Fondazione Cassa di Risparmio Padova e Rovigo under the project CONPHYT, starting grant in 2017; Swedish Research CouncilSwedish Research Council [822-2005-3332, 821-2010-6024, 821-2013-2304, 621-20145558, 2017-0065]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation [2005.0184]; Scientific and Technological Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [114F473]; Ministerio de Ciencia e InnovacionInstituto de Salud Carlos IIISpanish Government [SEV-2014-0398, FPA2017-84756-C4, EEBBI-15-09671]; Generalitat ValencianaGeneralitat Valenciana [PROMETEO/2019/005]; EU-FEDER fundsEuropean Union (EU); Croatian Science Foundation [7194]; Hungarian National Research and Innovation Office (NKFIH) [K128947, PD124717, GINOP-2.3.3-15-2016-00034]; Polish National Science Centre under the COPIN-IN2P3 project [2014-14-M-ST2-00738, 2016-22M-ST2-00269, 2017-25-B-ST2-01569]; Polish National Science Centre under the COPIGAL project [2014-14-M-ST2-00738, 2016-22M-ST2-00269, 2017-25-B-ST2-01569]; Polish National Science Centre under the POLITA project [2014-14-M-ST2-00738, 2016-22M-ST2-00269, 2017-25-B-ST2-01569] ; The authors would like to thank the AGATA and VAMOS collaborations. Special thanks go to the GANIL technical staff for their help in setting up the apparatuses and the good quality beam and to A. Poves for his fruitful comments. This work was partially supported by the European Union's Seventh Framework Programme for Research and Technological Development (grant no. 262010). A.G. acknowledges the support of the Fondazione Cassa di Risparmio Padova e Rovigo under the project CONPHYT, starting grant in 2017. the work was also supported (B.C, H.L., J.N. and U.J.) by Swedish Research Council under the grant agreements nos. 822-2005-3332, 821-2010-6024, 821-2013-2304, 621-20145558 and 2017-0065, and by the Knut and Alice Wallenberg Foundation grant no. 2005.0184, (B.S.) by the Scientific and Technological Council of Turkey (TUBITAK) under the project no. 114F473, (A.G., A.J. and R.P.) by the Ministerio de Ciencia e Innovacion under the contracts nos. SEV-2014-0398, FPA2017-84756-C4 and EEBBI-15-09671, by the Generalitat Valenciana under the grant agreement no. PROMETEO/2019/005 and by the EU-FEDER funds, (T.M and S.S.) by the Croatian Science Foundation under the project no. 7194, (I.K and D.S.) by the Hungarian National Research and Innovation Office (NKFIH) under the project nos. K128947, PD124717 and GINOP-2.3.3-15-2016-00034, (M.P.) by the Polish National Science Centre with the grants nos. 2014-14-M-ST2-00738, 2016-22M-ST2-00269 and 2017-25-B-ST2-01569 under the COPIN-IN2P3, COPIGAL and POLITA projects.

Background: Neutron-rich nuclei with protons in the fp shell show an onset of collectivity around N=40. Spectroscopic information is required to understand the underlying mechanism and to determine the relevant terms of the nucleon-nucleon interaction that are responsible for the evolution of the shell structure in this mass region. Methods: We report on the lifetime measurement of the first 2+ and 4+ states in 70,72 ,74Zn and the first 6+ state in 72Zn using the recoil distance Doppler shift method. The experiment was carried out at the INFN Laboratory of Legnaro with the AGATA demonstrator, first phase of the Advanced Gamma Tracking Array of highly segmented, high-purity germanium detectors coupled to the PRISMA magnetic spectrometer. The excited states of the nuclei of interest were populated in the deep inelastic scattering of a 76Ge beam impinging on a 238U target. Results: The maximum of collectivity along the chain of Zn isotopes is observed for 72Zn at N=42. An unexpectedly long lifetime of 20-5.2+1.8 ps was measured for the 4+ state in 74Zn. Conclusions: Our results lead to small values of the B(E2;41+→21+)/B(E2;21+→01+) ratio for 72,74Zn, suggesting a significant noncollective contribution to these excitations. These experimental results are not reproduced by state-of-the-art microscopic models and call for lifetime measurements beyond the first 2+ state in heavy zinc and nickel isotopes. © 2013 American Physical Society. ; This work has been partly financed by the European Union Seventh Framework Program FP7/2007-2013 under Grant Agreement No. 262010 ENSAR, the Polish MNiSW under Grant No. DPN/N190/AGATA/2009, the Spanish Ministerio de Ciencia e Innovacion under Contract No. FPA2011-29854-C04, and ´ the BMBF under Grant Nos. 05P12RDFN8 and 06DA9040I. ; Peer Reviewed

WOS: 000314826000009 ; The response of AGATA segmented HPGe detectors to gamma rays in the energy range 2-15 MeV was measured. The 15.1 MeV gamma rays were produced using the reaction d(B-11,n gamma)C-12 at E-beam=19.1 MeV, while gamma rays between 2 and 9 MeV were produced using an Am-Be-Fe radioactive source. The energy resolution and linearity were studied and the energy-to-pulse-height conversion resulted to be linear within 0.05%.Experimental interaction multiplicity distributions are discussed and compared with the results of Geant4 simulations. It is shown that the application of gamma-ray tracking allows a suppression of background radiation caused by n-capture in Ge nuclei. Finally the Doppler correction for the 15.1 MeV gamma line, performed using the position information extracted with Pulse-shape analysis is discussed. (C) 2012 Elsevier B.V. All rights reserved. ; European Union [262010-ENSAR]; MINECO Spain [AIC-D-2011-0746, FPA2011-29854]; Generalitat Valenciana, Spain [PROME-TEO/2010/101]; German BMBF [06K-167, 06KY205I] ; This research has received funding from the European Union Seventh Framework Program FP7/2007-2013 under grant Agreement no. 262010-ENSAR. A.G. activity has been supported by the MINECO Spain, under grants AIC-D-2011-0746, FPA2011-29854 and by and Generalitat Valenciana, Spain, under grant PROME-TEO/2010/101. We acknowledge the support by the German BMBF under Grants 06K-167 and 06KY205I.

19 pags., 11 figs., 3 tabs. ; The high-spin structures of Ba136 and Ba137 are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Ba136 is populated in a Xe136+U238 MNT reaction employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and in two Be9+Te130 fusion-evaporation reactions using the High-efficiency Observatory for γ-Ray Unique Spectroscopy (HORUS) at the FN tandem accelerator of the University of Cologne, Germany. Furthermore, both isotopes are populated in an elusive reaction channel in the B11+Te130 fusion-evaporation reaction utilizing the HORUS γ-ray array. The level scheme above the Jπ=10+ isomer in Ba136 is revised and extended up to an excitation energy of approximately 5.5 MeV. From the results of angular-correlation measurements, the Ex=3707- and Ex=4920-keV states are identified as the bandheads of positive- and negative-parity cascades. While the high-spin regimes of both Te132 and Xe134 are characterized by high-energy 12+→10+ transitions, the Ba136E2 ground-state band is interrupted by negative-parity states only a few hundred keV above the Jπ=10+ isomer. Furthermore, spins are established for several hitherto unassigned high-spin states in Ba137. The new results close a gap along the high-spin structure of N<82 Ba isotopes. Experimental results are compared to large-scale shell-model calculations employing the GCN50:82, Realistic SM, PQM130, and SN100PN interactions. The calculations suggest that the bandheads of the positive-parity bands in both isotopes are predominantly of proton character. ; Furthermore, we express our thanks to Dr. E. Teruya and Dr. N. Yoshinaga from Saitama University, Japan, for providing the results of their shellmodel calculation with the PQM130 interaction. The research leading to these results has received funding from the German BMBF under Contracts No. 05P15PKFN9 TP1 and No. 05P18PKFN9 TP1, from the European Union Seventh Framework Programme FP7/2007-2013 under Grant Agreement No. 262010 - ENSAR, from the Spanish Ministerio de Ciencia e Innovación under Contract No. FPA2011-29854- C04, from the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2014-57196-C5, and from the UK Science and Technology Facilities Council (STFC). L.K. and A.V. thank the Bonn-Cologne Graduate School of Physics and Astronomy (BCGS) for financial support. One of the authors (A. Gadea) has been supported by the Generalitat Valenciana, Spain, under Grant No. PROMETEOII/2014/019, and EU under the FEDER program.

13 pags., 12 figs., 4 tabs. ; Transition probabilities of intermediate-spin yrast and non-yrast excitations in Se80,82 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 Se80, the level lifetimes of the yrast (61+) and (81+) states and of a non-yrast band feeding the yrast 41+ 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 Se82, the level lifetimes of the yrast 61+ state and the yrare 42+ state and lifetime limits of the yrast (101+) state and of the 51- 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. ; This work was partially supported by the European Union Seventh Framework Program FP7/2007-2013 under Grant Agreement No. 262010 ENSAR, by the German Research Foundation (DFG) under Contract No. DE 1516/3-1, by the German BMBF under Grant No. 05P15PKFNA and by the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2014-57196-C5-4-P. J.L. and A.V. thank the Bonn-Cologne Graduate School of Physics and Astronomy (BCGS) for financial support. ; Peer Reviewed

The nuclear structure of neutron-rich nuclei close to the double-magic nucleus 78Ni has been investigated by measuring the lifetime of excited states. In this contribution, it will be presented the lifetime of the Jπ = 7=2 excited state at 981 keV of the 71Cu isotope, measured using the AGATA Demonstrator coupled to the PRISMA spectrometer and the Köln plunger setup. This is the first time this combined setup has been used for a lifetime measurement. ; This work has been partially supported by the grants FPA2008-06419, FPA2008-03774, AIC10-D-000605, AIC-D-2011-0764 and Consolider CSD2007-00042 from the Spanish Government and by INFN Italy. ; Peer Reviewed

18 pags., 11 figs., 4 tabs. ; The transitional nuclei Ba-134 and Ba-133 are investigated after multinucleon transfer employing the high-resolution Advanced GAmma Tracking Array coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and after fusion-evaporation reaction at the FN tandem accelerator of the University of Cologne, Germany. The J(pi) = 19/2(+) state at 1942 keV in Ba-133 is identified as an isomer with a half-life of 66.6(20) ns corresponding to a B(E1) value of 7.7(4) x 10(-6) e(2) fm(2) for the J(pi) = 19/2(+) to J(pi) = 19/2(-) transition. The level scheme of Ba-134 above the J(pi) = 10(+) isomer is extended to approximately 6 MeV. A pronounced backbending is observed at h omega = 0.38 MeV along the positive-parity yrast band. The results are compared to the high-spin systematics of the Z = 56 isotopes. Large-scale shell-model calculations employing the GCN50:82, SN100PN, SNV, PQM130, Realistic SM, and EPQQM interactions reproduce the experimental findings and elucidate the structure of the high-spin states. The shell-model calculations employing the GCN50:82 and PQM130 interactions reproduce alignment properties and provide detailed insight into the microscopic origin of this phenomenon in transitional Ba-134. ; The research leading to these results has received funding from the German BMBF under Contracts No. 05P15PKFN9 TP1 and No. 05P18PKFN9 TP1, from the European Union Seventh Framework Programme FP7/2007-2013 under Grant No. 262010-ENSAR, from the Spanish Ministerio de Ciencia e Innovación under Contract No. FPA2011-29854-C04, from the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2014- 57196-C5, and from the U.K. Science and Technology Facilities Council (STFC). One of the authors (A. Gadea) has been supported by the Generalitat Valenciana, Spain, under Grant No. PROMETEOII/2014/019 and EU under the FEDER program.

18 pags., 11 figs., 4 tabs. ; The transitional nuclei Ba-134 and Ba-133 are investigated after multinucleon transfer employing the high-resolution Advanced GAmma Tracking Array coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and after fusion-evaporation reaction at the FN tandem accelerator of the University of Cologne, Germany. The J(pi) = 19/2(+) state at 1942 keV in Ba-133 is identified as an isomer with a half-life of 66.6(20) ns corresponding to a B(E1) value of 7.7(4) x 10(-6) e(2) fm(2) for the J(pi) = 19/2(+) to J(pi) = 19/2(-) transition. The level scheme of Ba-134 above the J(pi) = 10(+) isomer is extended to approximately 6 MeV. A pronounced backbending is observed at h omega = 0.38 MeV along the positive-parity yrast band. The results are compared to the high-spin systematics of the Z = 56 isotopes. Large-scale shell-model calculations employing the GCN50:82, SN100PN, SNV, PQM130, Realistic SM, and EPQQM interactions reproduce the experimental findings and elucidate the structure of the high-spin states. The shell-model calculations employing the GCN50:82 and PQM130 interactions reproduce alignment properties and provide detailed insight into the microscopic origin of this phenomenon in transitional Ba-134. ; The research leading to these results has received funding from the German BMBF under Contracts No. 05P15PKFN9 TP1 and No. 05P18PKFN9 TP1, from the European Union Seventh Framework Programme FP7/2007-2013 under Grant No. 262010-ENSAR, from the Spanish Ministerio de Ciencia e Innovación under Contract No. FPA2011-29854-C04, from the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2014- 57196-C5, and from the U.K. Science and Technology Facilities Council (STFC). One of the authors (A. Gadea) has been supported by the Generalitat Valenciana, Spain, under Grant No. PROMETEOII/2014/019 and EU under the FEDER program.

WOS: 000350998600002 ; The level structure of the neutron-rich Cu-69, Cu-71, and Cu-73 isotopes has been investigated by means of multinucleon transfer reactions. The experiment was performed at Laboratori Nazionali di Legnaro using the AGATA Demonstrator array coupled to the PRISMA magnetic spectrometer. Lifetimes of excited states in Cu nuclei were measured with the recoil-distance Doppler-shift method. The resulting electromagnetic matrix elements for transitions from excited states in Cu-69,Cu-71,Cu-73 nuclei are used to assess the collective or single-particle character of these states. The results are compared with predictions of large-scale shell-model calculations, giving further insight into the evolution of the proton pf shell as neutrons fill the 1g(9/2) orbital. ; European Union Seventh Framework Program FP7 [262010]; ENSAR; MINECO, Spain [FPA2011-29854-C03, FPA2011-29854-C04, Consolider-Ingenio 2010 CSD2007-00042]; Generalitat Valenciana, Spain [PROMETEOII/2014/019] ; This work has been partially supported by the European Union Seventh Framework Program FP7/2007-2013 under Grant Agreement No. 262010, ENSAR and MINECO, Spain, under Grants No. FPA2011-29854-C03 and No. FPA2011-29854-C04, Generalitat Valenciana, Spain, under Grant No. PROMETEOII/2014/019, and MINECO, Spain, under Grant Consolider-Ingenio 2010 CSD2007-00042.