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1
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Cox I, Xu ZY, Grzywacz R, Ong WJ, Rasco BC, Kitamura N, Hoskins D, Neupane S, Ruland TJ, Allmond JM, King TT, Lubna RS, Rykaczewski KP, Schatz H, Sherrill BM, Tarasov OB, Ayangeakaa AD, Berg HC, Bleuel DL, Cerizza G, Christie J, Chester A, Davis J, Dembski C, Doetsch AA, Duarte JG, Estrade A, Fijałkowska A, Gray TJ, Good EC, Haak K, Hanai S, Harke JT, Harris C, Hermansen K, Hoff DEM, Jain R, Karny M, Kolos K, Laminack A, Liddick SN, Longfellow B, Lyons S, Madurga M, Mogannam MJ, Nowicki A, Ogunbeku TH, Owens-Fryar G, Rajabali MM, Richard AL, Ronning EK, Rose GE, Siegl K, Singh M, Spyrou A, Sweet A, Tsantiri A, Walters WB, Yokoyama R. Proton Shell Gaps in N=28 Nuclei from the First Complete Spectroscopy Study with FRIB Decay Station Initiator. Phys Rev Lett 2024; 132:152503. [PMID: 38682970 DOI: 10.1103/physrevlett.132.152503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/12/2023] [Accepted: 03/08/2024] [Indexed: 05/01/2024]
Abstract
The first complete measurement of the β-decay strength distribution of _{17}^{45}Cl_{28} was performed at the Facility for Rare Isotope Beams (FRIB) with the FRIB Decay Station Initiator during the second FRIB experiment. The measurement involved the detection of neutrons and γ rays in two focal planes of the FRIB Decay Station Initiator in a single experiment for the first time. This enabled an analytical consistency in extracting the β-decay strength distribution over the large range of excitation energies, including neutron unbound states. We observe a rapid increase in the β-decay strength distribution above the neutron separation energy in _{18}^{45}Ar_{27}. This was interpreted to be caused by the transitioning of neutrons into protons excited across the Z=20 shell gap. The SDPF-MU interaction with reduced shell gap best reproduced the data. The measurement demonstrates a new approach that is sensitive to the proton shell gap in neutron rich nuclei according to SDPF-MU calculations.
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Affiliation(s)
- I Cox
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Z Y Xu
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - R Grzywacz
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - W-J Ong
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - B C Rasco
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - N Kitamura
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - D Hoskins
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - S Neupane
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - T J Ruland
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - J M Allmond
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - T T King
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - R S Lubna
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - K P Rykaczewski
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - H Schatz
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - B M Sherrill
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - O B Tarasov
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - A D Ayangeakaa
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Triangle Universities Nuclear Laboratory, Duke University, Durham, North Carolina 27708, USA
| | - H C Berg
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - D L Bleuel
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - G Cerizza
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - J Christie
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - A Chester
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - J Davis
- Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - C Dembski
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - A A Doetsch
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - J G Duarte
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - A Estrade
- Department of Physics, Central Michigan University, Mount Pleasant, Michigan 48859, USA
| | - A Fijałkowska
- Faculty of Physics, University of Warsaw, PL 02-093 Warsaw, Poland
| | - T J Gray
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - E C Good
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - K Haak
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - S Hanai
- Center for Nuclear Study, University of Tokyo, Wako, Saitama 351-0198, Japan
| | - J T Harke
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - C Harris
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - K Hermansen
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - D E M Hoff
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R Jain
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - M Karny
- Faculty of Physics, University of Warsaw, PL 02-093 Warsaw, Poland
| | - K Kolos
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - A Laminack
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - S N Liddick
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - B Longfellow
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S Lyons
- Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - M Madurga
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - M J Mogannam
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Nowicki
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - T H Ogunbeku
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - G Owens-Fryar
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - M M Rajabali
- Physics Department, Tennessee Technological University, Cookeville, Tennessee 38505, USA
| | - A L Richard
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - E K Ronning
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - G E Rose
- University of California, Berkeley, Berkeley, California 94704, USA
| | - K Siegl
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - M Singh
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A Spyrou
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Sweet
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - A Tsantiri
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - W B Walters
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - R Yokoyama
- Center for Nuclear Study, University of Tokyo, Wako, Saitama 351-0198, Japan
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2
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Gray TJ, Allmond JM, Xu Z, King TT, Lubna RS, Crawford HL, Tripathi V, Crider BP, Grzywacz R, Liddick SN, Macchiavelli AO, Miyagi T, Poves A, Andalib A, Argo E, Benetti C, Bhattacharya S, Campbell CM, Carpenter MP, Chan J, Chester A, Christie J, Clark BR, Cox I, Doetsch AA, Dopfer J, Duarte JG, Fallon P, Frotscher A, Gaballah T, Harke JT, Heideman J, Huegen H, Holt JD, Jain R, Kitamura N, Kolos K, Kondev FG, Laminack A, Longfellow B, Luitel S, Madurga M, Mahajan R, Mogannam MJ, Morse C, Neupane S, Nowicki A, Ogunbeku TH, Ong WJ, Porzio C, Prokop CJ, Rasco BC, Ronning EK, Rubino E, Ruland TJ, Rykaczewski KP, Schaedig L, Seweryniak D, Siegl K, Singh M, Stuchbery AE, Tabor SL, Tang TL, Wheeler T, Winger JA, Wood JL. Microsecond Isomer at the N=20 Island of Shape Inversion Observed at FRIB. Phys Rev Lett 2023; 130:242501. [PMID: 37390416 DOI: 10.1103/physrevlett.130.242501] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/26/2023] [Indexed: 07/02/2023]
Abstract
Excited-state spectroscopy from the first experiment at the Facility for Rare Isotope Beams (FRIB) is reported. A 24(2)-μs isomer was observed with the FRIB Decay Station initiator (FDSi) through a cascade of 224- and 401-keV γ rays in coincidence with ^{32}Na nuclei. This is the only known microsecond isomer (1 μs≤T_{1/2}<1 ms) in the region. This nucleus is at the heart of the N=20 island of shape inversion and is at the crossroads of the spherical shell-model, deformed shell-model, and ab initio theories. It can be represented as the coupling of a proton hole and neutron particle to ^{32}Mg, ^{32}Mg+π^{-1}+ν^{+1}. This odd-odd coupling and isomer formation provides a sensitive measure of the underlying shape degrees of freedom of ^{32}Mg, where the onset of spherical-to-deformed shape inversion begins with a low-lying deformed 2^{+} state at 885 keV and a low-lying shape-coexisting 0_{2}^{+} state at 1058 keV. We suggest two possible explanations for the 625-keV isomer in ^{32}Na: a 6^{-} spherical shape isomer that decays by E2 or a 0^{+} deformed spin isomer that decays by M2. The present results and calculations are most consistent with the latter, indicating that the low-lying states are dominated by deformation.
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Affiliation(s)
- T J Gray
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - J M Allmond
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Z Xu
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - T T King
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - R S Lubna
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - H L Crawford
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - V Tripathi
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - B P Crider
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - R Grzywacz
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - S N Liddick
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - A O Macchiavelli
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - T Miyagi
- Department of Physics, Technische Universität Darmstadt, Darmstadt, Germany
- ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
| | - A Poves
- Departamento de Fìsica Teórica and IFT-UAM/CSIC, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - A Andalib
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - E Argo
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - C Benetti
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - S Bhattacharya
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - C M Campbell
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - M P Carpenter
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J Chan
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - A Chester
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - J Christie
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - B R Clark
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - I Cox
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - A A Doetsch
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - J Dopfer
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - J G Duarte
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - P Fallon
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A Frotscher
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - T Gaballah
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - J T Harke
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - J Heideman
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - H Huegen
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - J D Holt
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics, McGill University, Montréal, Quebec City H3A 2T8, Canada
| | - R Jain
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - N Kitamura
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - K Kolos
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - F G Kondev
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A Laminack
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - B Longfellow
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S Luitel
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - M Madurga
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - R Mahajan
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - M J Mogannam
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - C Morse
- National Nuclear Data Center, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - S Neupane
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - A Nowicki
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - T H Ogunbeku
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - W-J Ong
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - C Porzio
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - C J Prokop
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B C Rasco
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - E K Ronning
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - E Rubino
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - T J Ruland
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - K P Rykaczewski
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - L Schaedig
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - D Seweryniak
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - K Siegl
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - M Singh
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - A E Stuchbery
- Department of Nuclear Physics and Accelerator Applications, Research School of Physics, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - S L Tabor
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - T L Tang
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - T Wheeler
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - J A Winger
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - J L Wood
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA
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Beck S, Kootte B, Dedes I, Dickel T, Kwiatkowski AA, Lykiardopoulou EM, Plaß WR, Reiter MP, Andreoiu C, Bergmann J, Brunner T, Curien D, Dilling J, Dudek J, Dunling E, Flowerdew J, Gaamouci A, Graham L, Gwinner G, Jacobs A, Klawitter R, Lan Y, Leistenschneider E, Minkov N, Monier V, Mukul I, Paul SF, Scheidenberger C, Thompson RI, Tracy JL, Vansteenkiste M, Wang HL, Wieser ME, Will C, Yang J. Mass Measurements of Neutron-Deficient Yb Isotopes and Nuclear Structure at the Extreme Proton-Rich Side of the N=82 Shell. Phys Rev Lett 2021; 127:112501. [PMID: 34558921 DOI: 10.1103/physrevlett.127.112501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/30/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
High-accuracy mass measurements of neutron-deficient Yb isotopes have been performed at TRIUMF using TITAN's multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). For the first time, an MR-TOF-MS was used on line simultaneously as an isobar separator and as a mass spectrometer, extending the measurements to two isotopes further away from stability than otherwise possible. The ground state masses of ^{150,153}Yb and the excitation energy of ^{151}Yb^{m} were measured for the first time. As a result, the persistence of the N=82 shell with almost unmodified shell gap energies is established up to the proton drip line. Furthermore, the puzzling systematics of the h_{11/2}-excited isomeric states of the N=81 isotones are unraveled using state-of-the-art mean field calculations.
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Affiliation(s)
- Sönke Beck
- II. Physikalisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
| | - Brian Kootte
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Irene Dedes
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31 342 Kraków, Poland
- Institute of Physics, Marie Curie-Skłodowska University, PL-20 031 Lublin, Poland
| | - Timo Dickel
- II. Physikalisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
| | - A A Kwiatkowski
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Eleni Marina Lykiardopoulou
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Wolfgang R Plaß
- II. Physikalisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
| | - Moritz P Reiter
- II. Physikalisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, Scotland, United Kingdom
| | - Corina Andreoiu
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Julian Bergmann
- II. Physikalisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany
| | - Thomas Brunner
- Physics Department, McGill University, H3A 2T8 Montréal, Québec, Canada
| | - Dominique Curien
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67 000 Strasbourg, France
| | - Jens Dilling
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Jerzy Dudek
- Institute of Physics, Marie Curie-Skłodowska University, PL-20 031 Lublin, Poland
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67 000 Strasbourg, France
| | - Eleanor Dunling
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics, University of York, York YO10 5DD, United Kingdom
| | - Jake Flowerdew
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Abdelghafar Gaamouci
- Faculté de Physique, University of Science and Technology Houari Boumediene, BP 32, El Alia, 16111 Bab Ezzouar, Algiers, Algeria
| | - Leigh Graham
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - Gerald Gwinner
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Andrew Jacobs
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | | | - Yang Lan
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Erich Leistenschneider
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Nikolay Minkov
- Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, BG-1784 Sofia, Bulgaria
| | | | - Ish Mukul
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | | | - Christoph Scheidenberger
- II. Physikalisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
- Helmholtz Forschungsakademie Hessen für FAIR (HFHF), GSI Helmholtzzentrum für Schwerionenforschung, Campus Gießen, 35392 Gießen, Germany
| | - Robert I Thompson
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | | | | | - Hua-Lei Wang
- School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450001, China
| | - Michael E Wieser
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Christian Will
- II. Physikalisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany
| | - Jie Yang
- Institute of Physics, Marie Curie-Skłodowska University, PL-20 031 Lublin, Poland
- School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450001, China
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Longfellow B, Weisshaar D, Gade A, Brown BA, Bazin D, Brown KW, Elman B, Pereira J, Rhodes D, Spieker M. Shape Changes in the N=28 Island of Inversion: Collective Structures Built on Configuration-Coexisting States in ^{43}S. Phys Rev Lett 2020; 125:232501. [PMID: 33337204 DOI: 10.1103/physrevlett.125.232501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/06/2020] [Accepted: 10/30/2020] [Indexed: 06/12/2023]
Abstract
The neutron-rich nuclei in the N=28 island of inversion have attracted considerable experimental and theoretical attention, providing great insight into the evolution of shell structure and nuclear shape in exotic nuclei. In this work, for the first time, quadrupole collectivity is assessed simultaneously on top of the 3/2^{-} ground state and the 7/2^{-} shape-coexisting isomer of ^{43}S, putting the unique interpretation of shape and configuration coexistence at N=27 and 28 in the sulfur isotopic chain to the test. From an analysis of the electromagnetic transition strengths and quadrupole moments predicted within the shell model, it is shown that the onset of shape coexistence and the emergence of a simple collective structure appear suddenly in ^{43}S with no indication of such patterns in the N=27 isotone ^{45}Ar.
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Affiliation(s)
- B Longfellow
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - D Weisshaar
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Gade
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - B A Brown
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - D Bazin
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - K W Brown
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - B Elman
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - J Pereira
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - D Rhodes
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - M Spieker
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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5
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Michimasa S, Kobayashi M, Kiyokawa Y, Ota S, Yokoyama R, Nishimura D, Ahn DS, Baba H, Berg GPA, Dozono M, Fukuda N, Furuno T, Ideguchi E, Inabe N, Kawabata T, Kawase S, Kisamori K, Kobayashi K, Kubo T, Kubota Y, Lee CS, Matsushita M, Miya H, Mizukami A, Nagakura H, Oikawa H, Sakai H, Shimizu Y, Stolz A, Suzuki H, Takaki M, Takeda H, Takeuchi S, Tokieda H, Uesaka T, Yako K, Yamaguchi Y, Yanagisawa Y, Yoshida K, Shimoura S. Mapping of a New Deformation Region around ^{62}Ti. Phys Rev Lett 2020; 125:122501. [PMID: 33016755 DOI: 10.1103/physrevlett.125.122501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/12/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
We performed the first direct mass measurements of neutron-rich scandium, titanium, and vanadium isotopes around the neutron number 40 at the RIKEN RI Beam Factory using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of ^{58-60}Sc, ^{60-62}Ti, and ^{62-64}V were measured for the first time. The experimental results show that the two-neutron separation energies in the vicinity of ^{62}Ti increase compared to neighboring nuclei. This shows that the masses of Ti isotopes near N=40 are affected by the Jahn-Teller effect. Therefore, a development of Jahn-Teller stabilization appears below the Cr isotopes, and the systematics in Sc, Ti, and V isotopes suggest that ^{62}Ti is located close to the peak of the Jahn-Teller effect.
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Affiliation(s)
- S Michimasa
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - M Kobayashi
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Kiyokawa
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Ota
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - R Yokoyama
- Department of Physics and Astronomy, the University of Tennessee, Knoxville, Tennessee 37996, USA
| | - D Nishimura
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Natural Sciences, Tokyo City University, Tamazutsumi 1-28-1, Setagaya-ku, Tokyo 158-8557, Japan
| | - D S Ahn
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Baba
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - G P A Berg
- Department of Physics and Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - M Dozono
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - N Fukuda
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Furuno
- Department of Physics, Kyoto University, Kitashirakawa-Oiwake, Sakyo, Kyoto 606-8502, Japan
| | - E Ideguchi
- Research Center for Nuclear Physics, Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - N Inabe
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Kawabata
- Department of Physics, Kyoto University, Kitashirakawa-Oiwake, Sakyo, Kyoto 606-8502, Japan
| | - S Kawase
- Department of Advanced Energy Engineering Science, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
| | - K Kisamori
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Kobayashi
- Department of Physics, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - T Kubo
- Facility for Rare Isotope Beams, Michigan State University, 640 S Shaw Lane, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 S Shaw Lane, East Lansing, Michigan 48824, USA
| | - Y Kubota
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - C S Lee
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - M Matsushita
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Miya
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - A Mizukami
- Department of Physics, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - H Nagakura
- Department of Physics, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - H Oikawa
- Department of Physics, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - H Sakai
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Shimizu
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - A Stolz
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 S Shaw Lane, East Lansing, Michigan 48824, USA
| | - H Suzuki
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - M Takaki
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Takeda
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Takeuchi
- Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan
| | - H Tokieda
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Uesaka
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Yako
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Yamaguchi
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Yanagisawa
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Yoshida
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Shimoura
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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6
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Mijatović T, Kobayashi N, Iwasaki H, Bazin D, Belarge J, Bender PC, Brown BA, Dewald A, Elder R, Elman B, Gade A, Grinder M, Haylett T, Heil S, Loelius C, Longfellow B, Lunderberg E, Mathy M, Whitmore K, Weisshaar D. Lifetime Measurements and Triple Coexisting Band Structure in ^{43}S. Phys Rev Lett 2018; 121:012501. [PMID: 30028163 DOI: 10.1103/physrevlett.121.012501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/07/2018] [Indexed: 06/08/2023]
Abstract
Lifetime measurements of excited states in the neutron-rich nucleus ^{43}S were performed by applying the recoil-distance method on fast rare-isotope beams in conjunction with the Gamma-Ray Energy Tracking In-beam Nuclear Array. The new data based on γγ coincidences and lifetime measurements resolve a doublet of (3/2^{-}) and (5/2^{-}) states at low excitation energies. Results were compared to the π(sd)-ν(pf) shell model and antisymmetrized molecular dynamics calculations. The consistency with the theoretical calculations identifies a possible appearance of three coexisting bands near the ground state of ^{43}S: the K^{π}=1/2^{-} band built on a prolate-deformed ground state, a band built on an isomer with a 1f_{7/2}^{-1} character, and a suggested excited band built on a newly discovered doublet state. The latter further confirms the collapse of the N=28 shell closure in the neutron-rich region.
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Affiliation(s)
- T Mijatović
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - N Kobayashi
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - H Iwasaki
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - D Bazin
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - J Belarge
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - P C Bender
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - B A Brown
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Dewald
- Institut für Kernphysik der Universität zu Köln, Köln D-50937, Germany
| | - R Elder
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - B Elman
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Gade
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - M Grinder
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - T Haylett
- Department of Physics, University of York, Heslington, York YO10 5DD, United Kingdom
| | - S Heil
- Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt 64289, Germany
| | - C Loelius
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - B Longfellow
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - E Lunderberg
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - M Mathy
- Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt 64289, Germany
| | - K Whitmore
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - D Weisshaar
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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7
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Abstract
We clarify the origin of the anomalously hindered E2 decay from the 4_{1}^{+} level in ^{44}S by performing a novel many-body analysis in the shell model. Within a unified picture about the occurrence of isomerism in neutron-rich sulfur isotopes, the 4_{1}^{+} state is demonstrated to be a K=4 isomer dominated by the two-quasiparticle configuration νΩ^{π}=1/2^{-}⊗νΩ^{π}=7/2^{-}. The 4_{1}^{+} state in ^{44}S is a new type of high-K isomer which has significant triaxiality.
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Affiliation(s)
- Yutaka Utsuno
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan and Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Noritaka Shimizu
- Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takaharu Otsuka
- Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan and Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - Tooru Yoshida
- Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yusuke Tsunoda
- Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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8
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Meisel Z, George S, Ahn S, Browne J, Bazin D, Brown BA, Carpino JF, Chung H, Cyburt RH, Estradé A, Famiano M, Gade A, Langer C, Matoš M, Mittig W, Montes F, Morrissey DJ, Pereira J, Schatz H, Schatz J, Scott M, Shapira D, Smith K, Stevens J, Tan W, Tarasov O, Towers S, Wimmer K, Winkelbauer JR, Yurkon J, Zegers RGT. Mass measurements demonstrate a strong N=28 shell gap in argon. Phys Rev Lett 2015; 114:022501. [PMID: 25635542 DOI: 10.1103/physrevlett.114.022501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Indexed: 06/04/2023]
Abstract
We present results from recent time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory at Michigan State University. We report the first mass measurements of ^{48}Ar and ^{49}Ar and find atomic mass excesses of -22.28(31) MeV and -17.8(1.1) MeV, respectively. These masses provide strong evidence for the closed shell nature of neutron number N=28 in argon, which is therefore the lowest even-Z element exhibiting the N=28 closed shell. The resulting trend in binding-energy differences, which probes the strength of the N=28 shell, compares favorably with shell-model calculations in the sd-pf shell using SDPF-U and SDPF-MU Hamiltonians.
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Affiliation(s)
- Z Meisel
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, 48824 Michigan, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA
| | - S George
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA and Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
| | - S Ahn
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA
| | - J Browne
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, 48824 Michigan, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA
| | - D Bazin
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA
| | - B A Brown
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, 48824 Michigan, USA
| | - J F Carpino
- Department of Physics, Western Michigan University, Kalamazoo, 49008 Michigan, USA
| | - H Chung
- Department of Physics, Western Michigan University, Kalamazoo, 49008 Michigan, USA
| | - R H Cyburt
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA
| | - A Estradé
- School of Physics and Astronomy, The University of Edinburgh, EH8 9YL Edinburgh, United Kingdom
| | - M Famiano
- Department of Physics, Western Michigan University, Kalamazoo, 49008 Michigan, USA
| | - A Gade
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, 48824 Michigan, USA
| | - C Langer
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA
| | - M Matoš
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, 70803 Louisiana, USA
| | - W Mittig
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, 48824 Michigan, USA
| | - F Montes
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA
| | - D J Morrissey
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Department of Chemistry, Michigan State University, East Lansing, 48824 Michigan, USA
| | - J Pereira
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA
| | - H Schatz
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, 48824 Michigan, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA
| | - J Schatz
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA
| | - M Scott
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, 48824 Michigan, USA
| | - D Shapira
- Oak Ridge National Laboratory, Oak Ridge, 37831 Tennessee, USA
| | - K Smith
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA and Department of Physics, University of Notre Dame, South Bend, 46556 Indiana, USA
| | - J Stevens
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, 48824 Michigan, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA
| | - W Tan
- Department of Physics, University of Notre Dame, South Bend, 46556 Indiana, USA
| | - O Tarasov
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA
| | - S Towers
- Department of Physics, Western Michigan University, Kalamazoo, 49008 Michigan, USA
| | - K Wimmer
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA
| | - J R Winkelbauer
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, 48824 Michigan, USA
| | - J Yurkon
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA
| | - R G T Zegers
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 Michigan, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, 48824 Michigan, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, 48824 Michigan, USA
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9
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Gaudefroy L, Mittig W, Orr NA, Varet S, Chartier M, Roussel-Chomaz P, Ebran JP, Fernández-Domínguez B, Frémont G, Gangnant P, Gillibert A, Grévy S, Libin JF, Maslov VA, Paschalis S, Pietras B, Penionzhkevich YE, Spitaels C, Villari ACC. Direct mass measurements of 19B, 22C, 29F, 31Ne, 34Na and other light exotic nuclei. Phys Rev Lett 2012; 109:202503. [PMID: 23215476 DOI: 10.1103/physrevlett.109.202503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 07/27/2012] [Indexed: 06/01/2023]
Abstract
We report on direct time-of-flight based mass measurements of 16 light neutron-rich nuclei. These include the first determination of the masses of the Borromean drip-line nuclei (19)B, (22)C, and (29)F as well as that of (34)Na. In addition, the most precise determinations to date for (23)N and (31)Ne are reported. Coupled with recent interaction cross-section measurements, the present results support the occurrence of a two-neutron halo in (22)C, with a dominant ν2s(1/2)(2) configuration, and a single-neutron halo in (31)Ne with the valence neutron occupying predominantly the 2p(3/2) orbital. Despite a very low two-neutron separation energy the development of a halo in (19)B is hindered by the 1d(5/2)(2) character of the valence neutrons.
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Affiliation(s)
- L Gaudefroy
- GANIL, CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen, France.
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10
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Gallant AT, Bale JC, Brunner T, Chowdhury U, Ettenauer S, Lennarz A, Robertson D, Simon VV, Chaudhuri A, Holt JD, Kwiatkowski AA, Mané E, Menéndez J, Schultz BE, Simon MC, Andreoiu C, Delheij P, Pearson MR, Savajols H, Schwenk A, Dilling J. New precision mass measurements of neutron-rich calcium and potassium isotopes and three-nucleon forces. Phys Rev Lett 2012; 109:032506. [PMID: 22861844 DOI: 10.1103/physrevlett.109.032506] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 06/03/2012] [Indexed: 06/01/2023]
Abstract
We present precision Penning trap mass measurements of neutron-rich calcium and potassium isotopes in the vicinity of neutron number N=32. Using the TITAN system, the mass of 51K was measured for the first time, and the precision of the (51,52)Ca mass values were improved significantly. The new mass values show a dramatic increase of the binding energy compared to those reported in the atomic mass evaluation. In particular, 52Ca is more bound by 1.74 MeV, and the behavior with neutron number deviates substantially from the tabulated values. An increased binding was predicted recently based on calculations that include three-nucleon (3N) forces. We present a comparison to improved calculations, which agree remarkably with the evolution of masses with neutron number, making neutron-rich calcium isotopes an exciting region to probe 3N forces.
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Affiliation(s)
- A T Gallant
- TRIUMF, University of British Columbia, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
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Chevrier R, Daugas JM, Gaudefroy L, Ichikawa Y, Ueno H, Hass M, Haas H, Cottenier S, Aoi N, Asahi K, Balabanski DL, Fukuda N, Furukawa T, Georgiev G, Hayashi H, Iijima H, Inabe N, Inoue T, Ishihara M, Ishii Y, Kameda D, Kubo T, Nanao T, Neyens G, Ohnishi T, Rajabali MM, Suzuki K, Takeda H, Tsuchiya M, Vermeulen N, Watanabe H, Yoshimi A. Is the 7/2(1)- isomer state of 43S spherical? Phys Rev Lett 2012; 108:162501. [PMID: 22680712 DOI: 10.1103/physrevlett.108.162501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Indexed: 06/01/2023]
Abstract
We report on the spectroscopic quadrupole moment measurement of the 7/2(1)(-) isomeric state in (16)(43)S(27) [E*=320.5(5) keV, T(1/2)=415(3) ns], using the time dependent perturbed angular distribution technique at the RIKEN RIBF facility. Our value, |Q(s)|=23(3) efm(2), is larger than that expected for a single-particle state. Shell model calculations using the modern SDPF-U interaction for this mass region reproduce remarkably well the measured |Q(s)|, and show that non-negligible correlations drive the isomeric state away from a purely spherical shape.
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Force C, Grévy S, Gaudefroy L, Sorlin O, Cáceres L, Rotaru F, Mrazek J, Achouri NL, Angélique JC, Azaiez F, Bastin B, Borcea R, Buta A, Daugas JM, Dlouhy Z, Dombrádi Z, De Oliveira F, Negoita F, Penionzhkevich Y, Saint-Laurent MG, Sohler D, Stanoiu M, Stefan I, Stodel C, Nowacki F. Prolate-spherical shape coexistence at N=28 in 44S. Phys Rev Lett 2010; 105:102501. [PMID: 20867514 DOI: 10.1103/physrevlett.105.102501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Indexed: 05/29/2023]
Abstract
The structure of 44S has been studied by using delayed γ and electron spectroscopy. The decay rates of the 02+ isomeric state to the 2(1)+ and 0(1)+ states, measured for the first time, lead to a reduced transition probability B(E2: 2(1)+→0(2)+)=8.4(26) e(2) fm4 and a monopole strength ρ2(E0: 0(2)+→0(1)+)=8.7(7)×10(-3). Comparisons to shell model calculations point towards prolate-spherical shape coexistence, and a two-level mixing model is used to extract a weak mixing between the two configurations.
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Affiliation(s)
- C Force
- Grand Accélérateur National d'Ions Lours (GANIL), CEA/DSM-CNRS/IN2P3, Caen, France
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Gaudefroy L, Daugas JM, Hass M, Grévy S, Stodel C, Thomas JC, Perrot L, Girod M, Rossé B, Angélique JC, Balabanski DL, Fiori E, Force C, Georgiev G, Kameda D, Kumar V, Lozeva RL, Matea I, Méot V, Morel P, Singh BSN, Nowacki F, Simpson G. Shell Erosion and Shape Coexistence in (16)43S27. Phys Rev Lett 2009; 102:092501. [PMID: 19392514 DOI: 10.1103/physrevlett.102.092501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 12/17/2008] [Indexed: 05/27/2023]
Abstract
We report on the g-factor measurement of the first isomeric state in (16)43S27 [Ex=320.5(5) keV, T1/2=415(5) ns, and g=0.317(4)]. The 7/2- spin-parity of the isomer and the intruder nature of the ground state of the nucleus are experimentally established for the first time, providing direct and unambiguous evidence of the collapse of the N=28 shell closure in neutron-rich nuclei. The shell model, beyond the mean-field and semiempirical calculations, provides a very consistent description of this nucleus showing that a well deformed prolate and quasispherical states coexist at low energy.
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Dworschak M, Audi G, Blaum K, Delahaye P, George S, Hager U, Herfurth F, Herlert A, Kellerbauer A, Kluge HJ, Lunney D, Schweikhard L, Yazidjian C. Restoration of the n=82 shell gap from direct mass measurements of 132,134Sn. Phys Rev Lett 2008; 100:072501. [PMID: 18352543 DOI: 10.1103/physrevlett.100.072501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2007] [Indexed: 05/26/2023]
Abstract
A high-precision direct Penning trap mass measurement has revealed a 0.5-MeV deviation of the binding energy of (134)Sn from the currently accepted value. The corrected mass assignment of this neutron-rich nuclide restores the neutron-shell gap at N=82, previously considered to be a case of "shell quenching." In fact, the new shell gap value for the short-lived (132)Sn is larger than that of the doubly magic (48)Ca which is stable. The N=82 shell gap has considerable impact on fission recycling during the r process. More generally, the new finding has important consequences for microscopic mean-field theories which systematically deviate from the measured binding energies of closed-shell nuclides.
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Affiliation(s)
- M Dworschak
- GSI, Planckstrasse 1, 64291 Darmstadt, Germany. m.dworschak.gsi.de
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