1
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Spyrou A, Mücher D, Denissenkov PA, Herwig F, Good EC, Balk G, Berg HC, Bleuel DL, Clark JA, Dembski C, DeYoung PA, Greaves B, Guttormsen M, Harris C, Larsen AC, Liddick SN, Lyons S, Markova M, Mogannam MJ, Nikas S, Owens-Fryar J, Palmisano-Kyle A, Perdikakis G, Pogliano F, Quintieri M, Richard AL, Santiago-Gonzalez D, Savard G, Smith MK, Sweet A, Tsantiri A, Wiedeking M. First Study of the ^{139}Ba(n,γ)^{140}Ba Reaction to Constrain the Conditions for the Astrophysical i Process. PHYSICAL REVIEW LETTERS 2024; 132:202701. [PMID: 38829093 DOI: 10.1103/physrevlett.132.202701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/06/2023] [Accepted: 04/04/2024] [Indexed: 06/05/2024]
Abstract
New astronomical observations point to a nucleosynthesis picture that goes beyond what was accepted until recently. The intermediate "i" process was proposed as a plausible scenario to explain some of the unusual abundance patterns observed in metal-poor stars. The most important nuclear physics properties entering i-process calculations are the neutron-capture cross sections and they are almost exclusively not known experimentally. Here we provide the first experimental constraints on the ^{139}Ba(n,γ)^{140}Ba reaction rate, which is the dominant source of uncertainty for the production of lanthanum, a key indicator of i-process conditions. This is an important step towards identifying the exact astrophysical site of stars carrying the i-process signature.
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Affiliation(s)
- 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
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - D Mücher
- Institute for Nuclear Physics, University of Cologne, 50937 Köln, Germany
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3
| | - P A Denissenkov
- Department of Physics & Astronomy, University of Victoria, Post Office Box 1700, STN CSC, Victoria, British Columbia V8W2Y2, Canada
| | - F Herwig
- Department of Physics & Astronomy, University of Victoria, Post Office Box 1700, STN CSC, Victoria, British Columbia V8W2Y2, Canada
| | - E C Good
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - G Balk
- Department of Physics, Hope College, Holland, Michigan 49422-9000, 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
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - D L Bleuel
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550-9234, USA
| | - J A Clark
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, 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
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - P A DeYoung
- Department of Physics, Hope College, Holland, Michigan 49422-9000, USA
| | - B Greaves
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - M Guttormsen
- Department of Physics, University of Oslo, NO-0316 Oslo, Norway
| | - C Harris
- 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
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - A C Larsen
- Department of Physics, University of Oslo, NO-0316 Oslo, Norway
| | - 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
| | - S Lyons
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - M Markova
- Department of Physics, University of Oslo, NO-0316 Oslo, Norway
| | - 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
| | - S Nikas
- University of Jyväskyla, Accelerator Laboratory, Department of Physics 11 Post Office Box 35, FI-40014 University of Jyväskyla, Finland
| | - J 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
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Palmisano-Kyle
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - G Perdikakis
- Department of Physics, Central Michigan University, Mount Pleasant, Michigan 48859, USA
| | - F Pogliano
- Department of Physics, University of Oslo, NO-0316 Oslo, Norway
| | - M Quintieri
- 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 L Richard
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550-9234, USA
| | | | - G Savard
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M K Smith
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Sweet
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550-9234, 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
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - M Wiedeking
- SSC Laboratory, iThemba LABS, Post Office Box 722, Somerset West 7129, South Africa
- School of Physics, University of the Witwatersrand, Johannesburg 2050, South Africa
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2
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Dillmann I, Kester O, Baartman R, Chen A, Junginger T, Herwig F, Kaltchev D, Lennarz A, Planche T, Ruiz C, Vassh N. Measuring neutron capture cross sections of radioactive nuclei: From activations at the FZK Van de Graaff to direct neutron captures in inverse kinematics with a storage ring at TRIUMF. THE EUROPEAN PHYSICAL JOURNAL. A, HADRONS AND NUCLEI 2023; 59:105. [PMID: 37187510 PMCID: PMC10182137 DOI: 10.1140/epja/s10050-023-01012-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/13/2023] [Indexed: 05/17/2023]
Abstract
Measuring neutron capture cross sections of radioactive nuclei is a crucial step towards a better understanding of the origin of the elements heavier than iron. For decades, the precise measurement of direct neutron capture cross sections in the "stellar" energy range (eV up to a few MeV) was limited to stable and longer-lived nuclei that could be provided as physical samples and then irradiated with neutrons. New experimental methods are now being developed to extend these direct measurements towards shorter-lived radioactive nuclei (t 1 / 2 < 1 y). One project in this direction is a low-energy heavy-ion storage ring coupled to the ISAC facility at TRIUMF, Canada's accelerator laboratory in Vancouver BC, which has a compact neutron source in the ring matrix. Such a pioneering facility could be built within the next 10 years and store a wide range of radioactive ions provided directly from the existing ISOL facility, allowing for the first time to carry out direct neutron capture measurements on short-lived isotopes in inverse kinematics.
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Affiliation(s)
- Iris Dillmann
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | - Oliver Kester
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | - Richard Baartman
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | - Alan Chen
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 Canada
| | - Tobias Junginger
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | - Falk Herwig
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | | | - Annika Lennarz
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 Canada
| | - Thomas Planche
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | - Chris Ruiz
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
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3
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Lewis R, Couture A, Liddick SN, Spyrou A, Bleuel DL, Campo LC, Crider BP, Dombos AC, Guttormsen M, Kawano T, Larsen AC, Lewis AM, Mosby S, Perdikakis G, Prokop CJ, Quinn SJ, Renstrøm T, Siem S. Statistical (n, γ ) cross section model comparison for short-lived nuclei. THE EUROPEAN PHYSICAL JOURNAL. A, HADRONS AND NUCLEI 2023; 59:42. [PMID: 36915898 PMCID: PMC9998597 DOI: 10.1140/epja/s10050-023-00920-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 01/11/2023] [Indexed: 06/18/2023]
Abstract
UNLABELLED Neutron-capture cross sections of neutron-rich nuclei are calculated using a Hauser-Feshbach model when direct experimental cross sections cannot be obtained. A number of codes to perform these calculations exist, and each makes different assumptions about the underlying nuclear physics. We investigated the systematic uncertainty associated with the choice of Hauser-Feshbach code used to calculate the neutron-capture cross section of a short-lived nucleus. The neutron-capture cross section for 73 Zn (n, γ ) 74 Zn was calculated using three Hauser-Feshbach statistical model codes: TALYS, CoH, and EMPIRE. The calculation was first performed without any changes to the default settings in each code. Then an experimentally obtained nuclear level density (NLD) and γ -ray strength function ( γ SF ) were included. Finally, the nuclear structure information was made consistent across the codes. The neutron-capture cross sections obtained from the three codes are in good agreement after including the experimentally obtained NLD and γ SF , accounting for differences in the underlying nuclear reaction models, and enforcing consistent approximations for unknown nuclear data. It is possible to use consistent inputs and nuclear physics to reduce the differences in the calculated neutron-capture cross section from different Hauser-Feshbach codes. However, ensuring the treatment of the input of experimental data and other nuclear physics are similar across multiple codes requires a careful investigation. For this reason, more complete documentation of the inputs and physics chosen is important. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1140/epja/s10050-023-00920-0.
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Affiliation(s)
- R. Lewis
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Department of Chemistry, Michigan State University, East Lansing, MI 48824 USA
- Present Address: Zeno Power Systems, Inc., Washington, DC USA
| | - A. Couture
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - S. N. Liddick
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Department of Chemistry, Michigan State University, East Lansing, MI 48824 USA
| | - A. Spyrou
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 USA
| | - D. L. Bleuel
- Lawrence Livermore National Laboratory, Livermore, CA 94550 USA
| | - L. Crespo Campo
- Department of Physics, University of Oslo, 0316 Oslo, Norway
| | - B. P. Crider
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 USA
| | - A. C. Dombos
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 USA
| | - M. Guttormsen
- Department of Physics, University of Oslo, 0316 Oslo, Norway
| | - T. Kawano
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - A. C. Larsen
- Department of Physics, University of Oslo, 0316 Oslo, Norway
| | - A. M. Lewis
- Department of Nuclear Engineering, University of California Berkeley, Berkeley, CA 94720 USA
- Present Address: Naval Nuclear Laboratory, New York, USA
| | - S. Mosby
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - G. Perdikakis
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 USA
- Central Michigan University, Mount Pleasant, MI 48859 USA
| | - C. J. Prokop
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Department of Chemistry, Michigan State University, East Lansing, MI 48824 USA
| | - S. J. Quinn
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 USA
| | - T. Renstrøm
- Department of Physics, University of Oslo, 0316 Oslo, Norway
| | - S. Siem
- Department of Physics, University of Oslo, 0316 Oslo, Norway
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4
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Production of zirconium-88 via proton irradiation of metallic yttrium and preparation of target for neutron transmission measurements at DICER. Sci Rep 2023; 13:1736. [PMID: 36720963 PMCID: PMC9889377 DOI: 10.1038/s41598-023-27993-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 01/11/2023] [Indexed: 02/01/2023] Open
Abstract
A process for the production of tens to hundreds of GBq amounts of zirconium-88 (88Zr) using proton beams on yttrium was developed. For this purpose, yttrium metal targets (≈20 g) were irradiated in a ~16 to 34 MeV proton beam at a beam current of 100-200 µA at the Los Alamos Isotope Production Facility (IPF). The 88Zr radionuclide was produced and separated from the yttrium targets using hydroxamate resin with an elution yield of 94(5)% (1σ). Liquid DCl solution in D2O was selected as a suitable 88Zr sample matrix due to the high neutron transmission of deuterium compared to hydrogen and an even distribution of 88Zr in the sample matrix. The separated 88Zr was dissolved in DCl and 8 µL of the obtained solution was transferred to a tungsten sample can with a 1.2 mm diameter hole using a syringe and automated filling station inside a hot cell. Neutron transmission of the obtained 88Zr sample was measured at the Device for Indirect Capture Experiments on Radionuclides (DICER).
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5
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DICER: a new instrument for nuclear data for nuclear security. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08474-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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6
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Stamatopoulos A, Koehler P, Matyskin A, Bond EM, Bredeweg T, Couture A, Di Giovine B, Fassbender M, Hayes-Sterbenz AC, Keksis AL, Parsons K, Rusev G, Ullmann J, Vermeulen C. New capability for indirect neutron capture measurements: The DICER instrument at LANSCE. EPJ WEB OF CONFERENCES 2022. [DOI: 10.1051/epjconf/202226003006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Device for Indirect Capture on Radionuclides (DICER) implements a new indirect technique for (n,γ) studies in which the neutron capture rate is determined from analysis of resonance neutron transmission data. The DICER instrument and associated radionuclide production at the Isotope Production Facility (IPF), both at the Los Alamos Neutron Science Center (LANSCE), as well radioactive sample fabrication, have been under development in the last few years. First measurements on a radioactive sample (88Zr, t½=83.4 days), which was recently reported to have an extremely large thermal neutron capture cross section and resonance integral [1, 2], are planned for the winter of 2021. A performance overview, brief details on the 88Zr fabrication and proof of good operation results will be presented.
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7
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Whitehead TR, Lim Y, Holt JW. Global Microscopic Description of Nucleon-Nucleus Scattering with Quantified Uncertainties. PHYSICAL REVIEW LETTERS 2021; 127:182502. [PMID: 34767381 DOI: 10.1103/physrevlett.127.182502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 08/25/2021] [Accepted: 09/28/2021] [Indexed: 06/13/2023]
Abstract
We develop for the first time a microscopic global nucleon-nucleus optical potential with quantified uncertainties suitable for analyzing nuclear reaction experiments at next-generation rare-isotope beam facilities. Within the improved local density approximation and without any adjustable parameters, we begin by computing proton-nucleus and neutron-nucleus optical potentials from a set of five nuclear forces from chiral effective field theory for 1800 target nuclei in the mass range 12≤A≤242 for energies between 0 MeV<E≲150 MeV. We then parameterize a global optical potential for each chiral force that depends smoothly on the projectile energy as well as the target nucleus mass number and isospin asymmetry. Uncertainty bands for elastic scattering observables are generated from a full covariance analysis of the parameters entering in the description of our global optical potential and benchmarked against existing experimental data for stable target nuclei. Since our approach is purely microscopic, we anticipate a similar quality of the model for nucleon scattering on unstable isotopes.
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Affiliation(s)
- T R Whitehead
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
- Facility for Rare Isotope Beams, Michigan State University, Michigan 48824, USA
| | - Y Lim
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
- ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
- Department of Science Education, Ewha Womans University, Seoul 120-750, Korea
| | - J W Holt
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
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8
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Ngwetsheni C, Orce JN. How do we infer shell effects at high-excitation energies? A new spectroscopic probe to search for magic numbers. EPJ WEB OF CONFERENCES 2019. [DOI: 10.1051/epjconf/201922301045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The nuclear dipole polarizability is mainly governed by the dynamics of the giant dipole resonance and, assuming validity of the brink-Axel hypothesis, has been investigated along with the effects of the low-energy enhancement of the photon strength function for nuclides in medium- and heavy-mass nuclei. Cubic-polynomial fitsto both data sets extrapolated down to a gamma-ray energy of 0.1 MeV show a significantreduction of the nuclear dipole polarizability for semi-magic nuclei, with magic numbers N =28, 50 and 82, which supports shell effects at high-excitation energies in the the quasi-continuum region. This work assigns σ-2 values as sensitive measures of long-range correlations of the nuclear force and provides a new spectroscopic probe to search for “old” and “new” magic numbers at high-excitation energies.
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Ratkiewicz A, Cizewski JA, Escher JE, Potel G, Burke JT, Casperson RJ, McCleskey M, Austin RAE, Burcher S, Hughes RO, Manning B, Pain SD, Peters WA, Rice S, Ross TJ, Scielzo ND, Shand C, Smith K. Towards Neutron Capture on Exotic Nuclei: Demonstrating (d,pγ) as a Surrogate Reaction for (n,γ). PHYSICAL REVIEW LETTERS 2019; 122:052502. [PMID: 30822004 DOI: 10.1103/physrevlett.122.052502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 11/09/2018] [Indexed: 06/09/2023]
Abstract
The neutron-capture reaction plays a critical role in the synthesis of the elements in stars and is important for societal applications including nuclear power generation and stockpile-stewardship science. However, it is difficult-if not impossible-to directly measure neutron capture cross sections for the exotic, short-lived nuclei that participate in these processes. In this Letter we demonstrate a new technique which can be used to indirectly determine neutron-capture cross sections for exotic systems. This technique makes use of the (d,p) transfer reaction, which has long been used as a tool to study the structure of nuclei. Recent advances in reaction theory, together with data collected using this reaction, enable the determination of neutron-capture cross sections for short-lived nuclei. A benchmark study of the ^{95}Mo(d,p) reaction is presented, which illustrates the approach and provides guidance for future applications of the method with short-lived isotopes produced at rare isotope accelerators.
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Affiliation(s)
- A Ratkiewicz
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08901, USA
| | - J A Cizewski
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08901, USA
| | - J E Escher
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - G Potel
- Michigan State University, East Lansing, Michigan 48824, USA
- Facility for Rare Isotope Beams, East Lansing, Michigan 48824, USA
| | - J T Burke
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R J Casperson
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - M McCleskey
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
| | - R A E Austin
- Astronomy and Physics Department, Saint Mary's University, Halifax, NS BH3 3C3, Canada
| | - S Burcher
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08901, USA
| | - R O Hughes
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
- Department of Physics, University of Richmond, Virginia 23173, USA
| | - B Manning
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08901, USA
| | - S D Pain
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - W A Peters
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831, USA
| | - S Rice
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08901, USA
| | - T J Ross
- Department of Physics, University of Richmond, Virginia 23173, USA
| | - N D Scielzo
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - C Shand
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08901, USA
- Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom
| | - K Smith
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
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10
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Escher JE, Burke JT, Hughes RO, Scielzo ND, Casperson RJ, Ota S, Park HI, Saastamoinen A, Ross TJ. Constraining Neutron Capture Cross Sections for Unstable Nuclei with Surrogate Reaction Data and Theory. PHYSICAL REVIEW LETTERS 2018; 121:052501. [PMID: 30118303 DOI: 10.1103/physrevlett.121.052501] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/14/2018] [Indexed: 06/08/2023]
Abstract
Obtaining reliable data for nuclear reactions on unstable isotopes remains an extremely important task and a formidable challenge. Neutron capture cross sections-crucial ingredients for models of astrophysical processes, national security applications, and simulations of nuclear energy generation-are particularly elusive, as both projectile and target in the reaction are unstable. We demonstrate a new method for determining cross sections for neutron capture on unstable isotopes, using ^{87}Y(n,γ) as a prototype. To validate the method, a benchmark experiment is carried out to obtain the known ^{90}Zr(n,γ) cross section analogously. Our approach, which employs an indirect ("surrogate") measurement combined with theory, can be generalized to a larger class of nuclear reactions. It can be used both with traditional stable-beam experiments and in inverse kinematics at rare-isotope facilities.
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Affiliation(s)
- J E Escher
- Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - J T Burke
- Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - R O Hughes
- Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - N D Scielzo
- Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - R J Casperson
- Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - S Ota
- Cyclotron Institute, Texas A&M University, College Station, Texas 77840, USA
| | - H I Park
- Cyclotron Institute, Texas A&M University, College Station, Texas 77840, USA
| | - A Saastamoinen
- Cyclotron Institute, Texas A&M University, College Station, Texas 77840, USA
| | - T J Ross
- Department of Physics, University of Richmond, Richmond, Virginia 23173, USA
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11
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E. Escher J, T. Burke J, J. Casperson R, O. Hughes R, D. Scielzo N. One-nucleon pickup reactions and compound-nuclear decays. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201817803002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
One-nucleon transfer reactions, long used as a tool to study the structure of nuclei, are potentially valuable for determining reaction cross sections indirectly. This is significant, as many reactions of interest to astrophysics and other applications involve short-lived isotopes and cannot be measured directly. We describe a procedure for obtaining constraints for calculations of neutron capture cross sections using observables from experiments with transfer reactions. As a first step toward demonstrating the method, we outline the theory developments used to properly describe the production of the compound nucleus 88Y* via the one-nucleon pickup reaction 89Y(p,d)88Y* and test the description with data from a recent experiment. We indicate how this development can be used to extract the unknown 87Y(n,γ) cross section from 89Y(p,dγ) data. The example illustrates a more generally applicable method for determining unknown cross sections via a combination of theory and transfer (or inelastic scattering) experiments.
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Escher J, Burke J, Casperson R, Hughes R, Ota S, Scielzo N. Capture cross sections from (p,d) reactions. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201714612014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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13
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Schwengner R, Frauendorf S, Brown BA. Low-Energy Magnetic Dipole Radiation in Open-Shell Nuclei. PHYSICAL REVIEW LETTERS 2017; 118:092502. [PMID: 28306274 DOI: 10.1103/physrevlett.118.092502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Indexed: 06/06/2023]
Abstract
Low-energy M1 strength functions of ^{60,64,68}Fe are determined on the basis of large-scale shell-model calculations with the goal to study their development from the bottom to the middle of the neutron shell. We find that the zero-energy spike, which characterizes nuclei near closed shells, develops toward the middle of the shell into a bimodal structure composed of a weaker zero-energy spike and a scissorslike resonance around 3 MeV, where the summed strengths of the two structures change within only 8% around a value of 9.8 μ_{N}^{2}. The summed strength of the scissors region exceeds the total γ absorption strength from the ground state by a factor of about three, which explains the discrepancy between total strengths of the scissors resonance derived from (γ, γ^{'}) experiments and from experiments using light-ion induced reactions.
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Affiliation(s)
- R Schwengner
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - S Frauendorf
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - B A Brown
- National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
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14
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Tonchev A, Escher J, Scielzo N, Bedrossian P, Ilieva R, Humby P, Cooper N, Goddard P, Werner V, Tornow W, Rusev G, Kelley J, Pietralla N, Scheck M, Savran D, Löher B, Yates S, Crider B, Peters E, Tsoneva N, Goriely S. Capture cross sections on unstable nuclei. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201714601013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Spyrou A, Liddick SN, Naqvi F, Crider BP, Dombos AC, Bleuel DL, Brown BA, Couture A, Crespo Campo L, Guttormsen M, Larsen AC, Lewis R, Möller P, Mosby S, Mumpower MR, Perdikakis G, Prokop CJ, Renstrøm T, Siem S, Quinn SJ, Valenta S. Strong Neutron-γ Competition above the Neutron Threshold in the Decay of ^{70}Co. PHYSICAL REVIEW LETTERS 2016; 117:142701. [PMID: 27740831 DOI: 10.1103/physrevlett.117.142701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Indexed: 06/06/2023]
Abstract
The β-decay intensity of ^{70}Co was measured for the first time using the technique of total absorption spectroscopy. The large β-decay Q value [12.3(3) MeV] offers a rare opportunity to study β-decay properties in a broad energy range. Two surprising features were observed in the experimental results, namely, the large fragmentation of the β intensity at high energies, as well as the strong competition between γ rays and neutrons, up to more than 2 MeV above the neutron-separation energy. The data are compared to two theoretical calculations: the shell model and the quasiparticle random phase approximation (QRPA). Both models seem to be missing a significant strength at high excitation energies. Possible interpretations of this discrepancy are discussed. The shell model is used for a detailed nuclear structure interpretation and helps to explain the observed γ-neutron competition. The comparison to the QRPA calculations is done as a means to test a model that provides global β-decay properties for astrophysical calculations. Our work demonstrates the importance of performing detailed comparisons to experimental results, beyond the simple half-life comparisons. A realistic and robust description of the β-decay intensity is crucial for our understanding of nuclear structure as well as of r-process nucleosynthesis.
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Affiliation(s)
- A Spyrou
- 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
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - S N Liddick
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - F Naqvi
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - B P Crider
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - A C Dombos
- 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
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - D L Bleuel
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550-9234, 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
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Couture
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - L Crespo Campo
- Department of Physics, University of Oslo, NO-0316 Oslo, Norway
| | - M Guttormsen
- Department of Physics, University of Oslo, NO-0316 Oslo, Norway
| | - A C Larsen
- Department of Physics, University of Oslo, NO-0316 Oslo, Norway
| | - R Lewis
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - P Möller
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S Mosby
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - M R Mumpower
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - G Perdikakis
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
- Central Michigan University, Mt. Pleasant, Michigan 48859, USA
| | - C J Prokop
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - T Renstrøm
- Department of Physics, University of Oslo, NO-0316 Oslo, Norway
| | - S Siem
- Department of Physics, University of Oslo, NO-0316 Oslo, Norway
| | - S J Quinn
- 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
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - S Valenta
- Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, CZ-180 00 Prague 8, Czech Republic
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16
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Escher JE, Tonchev AP, Burke JT, Bedrossian P, Casperson RJ, Cooper N, Hughes RO, Humby P, Ilieva RS, Ota S, Pietralla N, Scielzo ND, Werner V. Compound-nuclear reactions with unstable nuclei: Constraining theory through innovative experimental approaches. EPJ WEB OF CONFERENCES 2016. [DOI: 10.1051/epjconf/201612212001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Liddick SN, Spyrou A, Crider BP, Naqvi F, Larsen AC, Guttormsen M, Mumpower M, Surman R, Perdikakis G, Bleuel DL, Couture A, Crespo Campo L, Dombos AC, Lewis R, Mosby S, Nikas S, Prokop CJ, Renstrom T, Rubio B, Siem S, Quinn SJ. Experimental Neutron Capture Rate Constraint Far from Stability. PHYSICAL REVIEW LETTERS 2016; 116:242502. [PMID: 27367386 DOI: 10.1103/physrevlett.116.242502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Indexed: 06/06/2023]
Abstract
Nuclear reactions where an exotic nucleus captures a neutron are critical for a wide variety of applications, from energy production and national security, to astrophysical processes, and nucleosynthesis. Neutron capture rates are well constrained near stable isotopes where experimental data are available; however, moving far from the valley of stability, uncertainties grow by orders of magnitude. This is due to the complete lack of experimental constraints, as the direct measurement of a neutron-capture reaction on a short-lived nucleus is extremely challenging. Here, we report on the first experimental extraction of a neutron capture reaction rate on ^{69}Ni, a nucleus that is five neutrons away from the last stable isotope of Ni. The implications of this measurement on nucleosynthesis around mass 70 are discussed, and the impact of similar future measurements on the understanding of the origin of the heavy elements in the cosmos is presented.
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Affiliation(s)
- S N Liddick
- National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Spyrou
- National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - B P Crider
- National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA
| | - F Naqvi
- National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA
| | - A C Larsen
- Department of Physics, University of Oslo, N-0316 Oslo, Norway
| | - M Guttormsen
- Department of Physics, University of Oslo, N-0316 Oslo, Norway
| | - M Mumpower
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - R Surman
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - G Perdikakis
- National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
- Central Michigan University, Mount Pleasant, Michigan 48859, USA
| | - D L Bleuel
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550-9234, USA
| | - A Couture
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - L Crespo Campo
- Department of Physics, University of Oslo, N-0316 Oslo, Norway
| | - A C Dombos
- National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - R Lewis
- National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - S Mosby
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S Nikas
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
- Central Michigan University, Mount Pleasant, Michigan 48859, USA
| | - C J Prokop
- National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - T Renstrom
- Department of Physics, University of Oslo, N-0316 Oslo, Norway
| | - B Rubio
- IFIC, CSIC-Universidad de Valencia, 46071 Valencia, Spain
| | - S Siem
- Department of Physics, University of Oslo, N-0316 Oslo, Norway
| | - S J Quinn
- National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
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18
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Renstrøm T, Nyhus HT, Utsunomiya H, Larsen AC, Siem S, Guttormsen M, Filipescu DM, Gheorghe I, Goriely S, Bernstein LA, Bleuel DL, Glodariu T, Görgen A, Hagen TW, Lui YW, Negi D, Ruud IE, Şahin E, Schwengner R, Shima T, Takahisa K, Tesileanu O, Tornyi TG, Tveten GM, Wiedeking M. First evidence of low energy enhancement in Ge isotopes. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20159304003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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