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Author Delafosse, C. et al; Gadea, A.; Perez-Vidal, R.M.; Domingo-Pardo, C.
Title Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the Ni-78 Region: A Hint from Lifetime Measurements Type Journal Article
Year 2018 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 121 Issue 19 Pages 192502 - 7pp
Keywords
Abstract (down) Lifetime measurements of excited states of the light N = 52 isotones Kr-88, Se-86, and Ge-84 have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2; 2(+)-> 0(+)) and B(E2; 4(+)-> 2(+)) were obtained for the first time for the hard-to-reach 84Ge. While the B(E2; 2(+)-> 0(+) ) values of Kr-88, Se-86 saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g(7/2), 1h(11/2)) space of an inert Ni-78 core, the value obtained for Ge-84 largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N less than or similar to 49, extend beyond N = 50. The onset of collectivity at Z = 32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector rho field in shell-structure evolution.
Address [Delafosse, C.; Verney, D.; Marevic, P.; Gottardo, A.; Babo, M.; Franchoo, S.; Ibrahim, F.; Matea, I; Olivier, L.; Portail, C.; Stefan, I] Univ Paris Saclay, Univ Paris Sud, CNRS IN2P3, Inst Phys Nucl, F-91406 Orsay, France, Email: verney@ipno.in2p3.fr
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Medium
Area Expedition Conference
Notes WOS:000449791600008 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3800
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Author Goldkuhle, A. et al; Perez-Vidal, R.M.
Title Lifetime measurements of excited states in neutron-rich Ti-53: Benchmarking effective shell-model interactions Type Journal Article
Year 2020 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 102 Issue 5 Pages 054334 - 10pp
Keywords
Abstract (down) Level lifetimes of the yrast (5/2(-)) to 13/2(-) states in the neutron-rich nucleus Ti-53, produced in a multinucleon-transfer reaction, have been measured for the first time. The recoil distance Doppler-shift method was employed and lifetimes of the excited states were extracted by a lineshape analysis aided by GEANT4-based Monte-Carlo simulations. The experiment was performed at the Grand Accelerateur National d'Ions Lourds facility in Caen, France, by using the Advanced Gamma Tracking Array for the gamma-ray detection coupled to the large-acceptance variable mode spectrometer for an event-by-event particle identification and the Cologne plunger for deep-inelastic reactions. Reduced transition probabilities, deduced from the lifetimes, give new information on the nuclear structure of Ti-53, and are used to benchmark different shell-model calculations using established interactions in the f p shell.
Address [Goldkuhle, A.; Blazhev, A.; Fransen, C.; Dewald, A.; Beckers, M.; Birkenbach, B.; Braunroth, T.; Eberth, J.; Hess, H.; Jolie, J.; Litzinger, J.; Mueller-Gatermann, C.; Reiter, P.; Vogt, A.; Warr, N.; Zell, K. O.] Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany, Email: agoldkuhle@ikp.uni-koeln.de
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000595152800006 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4629
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Author Lauritsen, T. et al; Perez-Vidal, R.M.
Title Characterization of a gamma-ray tracking array: A comparison of GRETINA and Gammasphere using a Co-60 source Type Journal Article
Year 2016 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 836 Issue Pages 46-56
Keywords Segmented germanium detectors; Efficiency measurements; gamma-Ray tracking; Gammasphere; GRETINA; GRETA; gamma-Ray spectroscopy; Nuclear structure
Abstract (down) In this paper; we provide a formalism for the characterization of tracking arrays with emphasis on the proper corrections required to extract their photopeak efficiencies and peak-to-total ratios. The methods are first applied to Gammasphere, a well characterized 4 pi array based on the principle of Compton suppression, and subsequently to GRETINA. The tracking efficiencies are then discussed and some guidelines as to what clustering angle to use in the tracking algorithm are presented. It was possible, using GEANT4 simulations, to scale the measured efficiencies up to the expected values for the full 4 pi implementation of GRETA.
Address [Lauritsen, T.; Zhu, S.; Ayangeakaa, A. D.; Carpenter, M. P.; Greene, J. P.; Janssens, R. V. F.; Khoo, T. L.; Seweryniak, D.] Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA, Email: torben@anl.gov
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000385601400007 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2830
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Author Lalovic, N.; Louchart, C.; Michelagnoli, C.; Perez-Vidal, R.M.; Ralet, D.; Gerl, J.; Rudolph, D.; Arici, T.; Bazzacco, D.; Clement, E.; Gadea, A.; Kojouharov, I.; Korichi, A.; Labiche, M.; Ljungvall, J.; Lopez-Martens, A.; Nyberg, J.; Pietralla, N.; Pietri, S.; Stezowski, O.
Title Performance of the AGATA gamma-ray spectrometer in the PreSPEC set-up at GSI Type Journal Article
Year 2016 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 806 Issue Pages 258-266
Keywords Gamma-ray spectroscopy; Gamma-ray tracking; Nuclear structure; Pulse shape analysis; HPGe detectors
Abstract (down) In contemporary nuclear physics, the European Advanced GAmma Tracking Array (AGATA) represents a crucial detection system for cutting-edge nuclear structure studies. AGATA consists of highly segmented high-purity germanium crystals and uses the pulse-shape analysis technique to determine both the position and the energy of the y-ray interaction points in the crystals. It is the tracking algorithms that deploy this information and enable insight into the sequence of interactions, providing information on the full or partial absorption of the 7 ray. A series of dedicated performance measurements for an AGATA set-up comprising 21 crystals is described. This set-up was used within the recent PreSPEC-AGATA experimental campaign at the GSI Helmholtzzentrum fur Schwerionenforschung. Using the radioactive sources Co-56, Co-60 and Eu-152, absolute and normalized efficiencies and the peak-to-total of the array were measured. These quantities are discussed using different data analysis procedures. The quality of the pulse-shape analysis and the tracking algorithm are evaluated. The agreement between the experimental data and the Geant4 simulations is also investigated.
Address [Lalovic, N.; Rudolph, D.] Lund Univ, Dept Phys, SE-22100 Lund, Sweden, Email: Natasa.Lalovic@nuclear.lu.se
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000364856100035 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2463
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Author Banik, R. et al; Perez-Vidal, R.M.
Title High-spin states above the isomers in neutron-rich iodine nuclei near N=82 Type Journal Article
Year 2020 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 102 Issue 4 Pages 044329 - 15pp
Keywords
Abstract (down) Excited states of neutron-rich iodine isotopes I130-134 above the high-spin isomers have been identified using prompt-delayed gamma-ray spectroscopy. The iodine isotopes were produced as fission fragments of fusion-fission and transfer induced fission of 9Be(U-238, f) at a beam energy of 6.2 MeV/u. The complete (A, Z) identification was obtained using the large acceptance magnetic spectrometer VAMOS++. The AGATA gamma-ray tracking array was used to detect the prompt gamma rays while the delayed gamma rays (in the time range of 100 ns to 200 μs) from the isomeric states were identified by the EXOGAM segmented clover detectors, placed behind the focal plane of the VAMOS++ spectrometer. The high-spin states above the (8(-)) isomers in I-130,I-132 were populated for the first time, and a new isomer in I-132 was identified. A new gamma-ray transition was also assigned to the level structure of I-134. Prompt transitions above the 19/2- isomer were identified in I-131,I-133, for the first time. The level structures are interpreted in terms of the systematics of odd-Z nuclei above the Z = 50 shell closure and large-scale shell model calculations.
Address [Banik, R.; Bhattacharyya, S.; Bhattacharya, Soumik; Mukherjee, G.] Variable Energy Cyclotron Ctr, 1-AF Bidhannagar, Kolkata 700064, India, Email: sarmi@vecc.gov.in
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000583198600001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4588
Permanent link to this record