Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Persistence of the Z=28 shell gap in A=75 isobars: Identification of a possible (1/ 2– ) μs isomer in Co 75 and β decay to Ni 75

Journal Article · · Physical Review. C
 [1];  [2];  [3];  [4];  [5];  [6];  [3];  [7];  [3];  [8];  [9];  [10];  [11];  [12];  [13];  [14];  [15];  [16];  [17];  [18] more »;  [3];  [19];  [3];  [20];  [21];  [3];  [21];  [19];  [4];  [22];  [19];  [23];  [24];  [17];  [17];  [25];  [6];  [21];  [19];  [26];  [4];  [27];  [28] « less
  1. Inst. de Física Corpuscular, Valencia (Spain); Inst. de Estructura de la Materia, Madrid (Spain); OSTI
  2. Inst. de Física Corpuscular, Valencia (Spain)
  3. RIKEN Nishina Center, Saitama (Japan)
  4. Univ. of Tokyo (Japan)
  5. Univ. Autónoma de Madrid (Spain)
  6. Univ. of Tokyo (Japan); RIKEN Nishina Center, Saitama (Japan)
  7. Univ. of Brighton (United Kingdom); RIKEN Nishina Center, Saitama (Japan)
  8. Univ. Grenoble-Alpes (France); ILL (France); RIKEN Nishina Center, Saitama (Japan)
  9. Univ. of Notre Dame, IN (United States)
  10. Peking Univ., Beijing (China)
  11. RIKEN Nishina Center, Saitama (Japan); Extreme Light Infrastructure-Nuclear Physics (ELI-NP) and Horia Hulubei National Inst. for Physics and Nuclear Engineering (IFIN-HH), Bucharest-Magurele (Romania)
  12. Tohoku Univ., Sendai (Japan)
  13. Univ. Autónoma de Madrid (Spain); Inst. de Estructura de la Materia, Madrid (Spain); RIKEN Nishina Center, Saitama (Japan)
  14. Inst. for Nuclear Research (Atomki), Debrecen (Hungary); RIKEN Nishina Center, Saitama (Japan)
  15. Beihang Univ., Beijing (China)
  16. Peking Univ., Beijing (China); RIKEN Nishina Center, Saitama (Japan)
  17. Osaka Univ. (Japan)
  18. Tokyo Univ. of Science, Chiba (Japan)
  19. Univ. Paris-Saclay (France)
  20. Univ. di Padova and INFN Sezione di Padova (Italy); Technische Univ. Darmstadt (Germany)
  21. GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany)
  22. Univ. di Padova and INFN Sezione di Padova (Italy)
  23. Istituto Nazionale di Fisica Nucleare, Legnaro (Italy)
  24. Yale Univ., New Haven, CT (United States)
  25. Univ. of Oslo (Norway)
  26. Univ. Paris-Saclay, Orsay (France); RIKEN Nishina Center, Saitama (Japan)
  27. Yale Univ., New Haven, CT (United States); Technische Universität Darmstadt (Germany)
  28. Inst. for Nuclear Research (Atomki), Debrecen (Hungary)
+ Show Author Affiliations

Here, the evolution of shell structure around doubly magic exotic nuclei is of great interest in nuclear physics and astrophysics. In the ‘southwest’ region of 78Ni, the development of deformation might trigger a major shift in our understanding of explosive nucleosynthesis. To this end, new spectroscopic information on key close-lying nuclei is very valuable. We intend to measure the isomeric and β decay of 75Co, with one-proton and two-neutron holes relative to 78Ni, to access new nuclear structure information in 75Co and its β-decay daughters 75Ni and 74Ni. The nucleus 75Co is produced in relativistic in-flight fission reactions of 238U at the Radioactive Ion Beam Factory in the RIKEN Nishina Center. Its isomeric and β decay are studied exploiting the BigRIPS and EURICA setups. We obtain partial β-decay spectra for 75Ni and 74Ni, and report a new isomeric transition in 75Co. The energy [Eγ = 1914(2)keV] and half-life [t1/2 = 13(6) μs] of the delayed γ ray lend support for the existence of a Jπ = (1/2–) isomeric state at 1914(2) keV. A comparison with PFSDG-U shell-model calculations provides a good account for the observed states in 75Ni, but the first calculated 1/2– level in 75Co, a prolate K = 1/2 state, is predicted about 1 MeV below the observed (1/2–) level. The spherical-like structure of the lowest-lying excited states in 75Ni is proved. In the case of 75Co, the results suggest that the dominance of the spherical configurations over the deformed ones might be stronger than expected below 78Ni. Further experimental efforts to discern the nature of the Jπ = (1/2–) isomer are necessary.

Research Organization:
Yale Univ., New Haven, CT (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
FG02-91ER40609
OSTI ID:
1850007
Journal Information:
Physical Review. C, Journal Name: Physical Review. C Journal Issue: 6 Vol. 103; ISSN 2469-9985
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English

References (66)

The essential decay of pandemonium: A demonstration of errors in complex beta-decay schemes journal November 1977
Studies of odd-mass Co isotopes in the unified model journal March 1968
Coupling of a three-particle (hole) valence-shell cluster to quadrupole vibrations (Alaga model): The Z = 50 region: odd Ag and I isotopes; and the Z = 28 region: odd Mn and Ga isotopes journal August 1973
Installation and commissioning of EURICA – Euroball-RIKEN Cluster Array
  • Söderström, P. -A.; Nishimura, S.; Doornenbal, P.
  • Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 317 https://doi.org/10.1016/j.nimb.2013.03.018
journal December 2013
Identification and separation of radioactive isotope beams by the BigRIPS separator at the RIKEN RI Beam Factory journal December 2013
Enhanced collectivity in 74Ni journal September 2010
Decay properties of 68,69,70 Mn: Probing collectivity up to N = 44 in Fe isotopic chain journal December 2015
Type II shell evolution in A = 70 isobars from the N ≥ 40 island of inversion journal February 2017
Shell evolution beyond Z = 28 and N = 50: Spectroscopy of 81,82,83,84 Zn journal October 2017
Partial conservation of seniority and its unexpected influence on E2 transitions in g 9/2 nuclei journal October 2017
Is seniority a partial dynamic symmetry in the first ν g 9/2 shell? journal June 2018
Shell evolution of N = 40 isotones towards 60Ca: First spectroscopy of 62Ti journal January 2020
78Ni revealed as a doubly magic stronghold against nuclear deformation journal May 2019
The impact of nuclear shape on the emergence of the neutron dripline journal November 2020
Exotic nuclei and nuclear forces journal January 2013
The role of shell evolution in shape coexistence journal January 2016
The AME2016 atomic mass evaluation (II). Tables, graphs and references journal March 2017
Beta-gamma spectroscopy at RIBF journal January 2012
Probing the role of proton cross-shell excitations in Ni 70 using nucleon knockout reactions journal September 2019
Shell structure of the neutron-rich isotopes Co 69 , 71 , 73 journal March 2020
Precision mass measurements of Fe 67 and Co 69 , 70 : Nuclear structure toward N = 40 and impact on r -process reaction rates journal April 2020
Transition strengths in the neutron-rich Ni 73 , 74 , 75 isotopes journal July 2020
β decay of Ni 75 and the systematics of the low-lying level structure of neutron-rich odd- A Cu isotopes journal September 2020
Mapping of fragmented ν f 5 / 2 → π f 7 / 2 transitions in the Co 73 → Ni 73 decay journal October 2020
β decay of the very neutron-deficient Ge 60 and Ge 62 nuclei journal January 2021
Seniority conservation and seniority violation in the g 9 / 2 shell journal April 2006
Relations between coefficients of fractional parentage journal June 2007
Energy expressions for n = 3 and 4 systems in a single- j shell journal March 2010
Half-lives and branchings for β -delayed neutron emission for neutron-rich Co–Cu isotopes in the r -process journal August 2010
Island of inversion around Cr 64 journal November 2010
Partial conservation of seniority in the j = 9 / 2 shell: Analytic and numerical studies journal January 2011
Multiple β − decaying states in 194 Re: Shape evolution in neutron-rich osmium isotopes journal March 2012
β decay of 71 , 73 Co: Probing single-particle states approaching doubly magic 78 Ni journal March 2012
β -delayed γ -ray spectroscopy of 203 , 204 Au and 200 − 202 Pt journal July 2013
Novel shape evolution in exotic Ni isotopes and configuration-dependent shell structure journal March 2014
Analogous intruder behavior near Ni, Sn, and Pb isotopes journal August 2015
Two-hole structure outside Ni 78 : Existence of a μ s isomer of Co 76 and β decay into Ni 76 journal November 2015
Low-lying excitations in Ni 72 journal March 2016
β decay of deformed r -process nuclei near A = 80 and A = 160 , including odd- A and odd-odd nuclei, with the Skyrme finite-amplitude method journal November 2016
Ultrafast-timing lifetime measurements in Ru 94 and Pd 96 : Breakdown of the seniority scheme in N = 50 isotones journal January 2017
Observation of new neutron-rich Mn, Fe, Co, Ni, and Cu isotopes in the vicinity of Ni 78 journal May 2017
Simultaneous investigation of the T = 1 ( J π = 0 + ) and T = 0 ( J π = 9 + ) β decays in Br 70 journal June 2017
Inelastic scattering of neutron-rich Ni and Zn isotopes off a proton target journal April 2018
Structure of Fe 70 : Single-particle and collective degrees of freedom journal January 2019
Nuclear structure of Ni 76 from the ( p , 2 p ) reaction journal January 2019
Partial Conservation of Seniority and Nuclear Isomerism journal February 2008
New Isomers in the Full Seniority Scheme of Neutron-Rich Lead Isotopes: The Role of Effective Three-Body Forces journal October 2012
Quadrupole Collectivity in Neutron-Rich Fe and Cr Isotopes journal June 2013
β -Decay Half-Lives of Co 76 , 77 , Ni 79 , 80 , and Cu 81 : Experimental Indication of a Doubly Magic Ni 78 journal July 2014
Quadrupole Transition Strength in the Ni 74 Nucleus and Core Polarization Effects in the Neutron-Rich Ni Isotopes journal October 2014
Extension of the N = 40 Island of Inversion towards N = 50 : Spectroscopy of Cr 66 , Fe 70 , 72 journal November 2015
Direct Lifetime Measurements of the Excited States in Ni 72 journal March 2016
Quantum Phase Transition in the Shape of Zr isotopes journal October 2016
Shape Coexistence in Ni 78 as the Portal to the Fifth Island of Inversion journal December 2016
Shell Evolution towards Ni 78 : Low-Lying States in Cu 77 journal June 2017
Persistence of the Z = 28 Shell Gap Around Ni 78 : First Spectroscopy of Cu 79 journal November 2017
Binding Energy of Cu 79 : Probing the Structure of the Doubly Magic Ni 78 from Only One Proton Away journal November 2017
Underlying Structure of Collective Bands and Self-Organization in Quantum Systems journal November 2019
Absence of Low-Energy Shape Coexistence in Ge 80 : The Nonobservation of a Proposed Excited 0 2 + Level at 639 keV journal October 2020
Magicity of the N 68 i Semidouble-Closed-Shell Nucleus Probed by Gamow-Teller Decay of the Odd- A Neighbors journal November 1999
Half-Life of the Doubly Magic r -Process Nucleus N 78 i journal March 2005
Evolution of Nuclear Shells due to the Tensor Force journal November 2005
Enhanced Core Polarization in Ni 70 and Zn 74 journal June 2006
The shell model as a unified view of nuclear structure journal June 2005
Evolution of shell structure in exotic nuclei journal March 2020
Identification of 45 New Neutron-Rich Isotopes Produced by In-Flight Fission of a 238 U Beam at 345 MeV/nucleon journal July 2010

Similar Records

β -delayed neutron emission of Mn64, Cr62 , and Fe65
Journal Article · Tue Aug 27 00:00:00 EDT 2024 · Physical Review. C · OSTI ID:2438190
β-delayed neutron spectroscopy of Co70,72 ground-state and isomeric-state decays
Journal Article · Mon Jun 10 00:00:00 EDT 2024 · Physical Review. C · OSTI ID:2438847

Related Subjects

59 ≤ A ≤ 89
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Beta decay
Electromagnetic transitions
Energy levels & level densities
Isomer decays
Nuclear structure & decays
Physics
Rare & new isotopes
Shell model