First measurement of β-decay strength to neutron-unbound states in the decay of Cu isotopes with N≥50

ORAL

Abstract

Cu isotopes with N ≥ 50  lying on the r-process pathway offer a laboratory to study the nature of nuclear forces in nuclei with a large neutron-to-proton (N/Z) ratio and also engage in β-delayed neutron emission. Most of the β-decay strength from the decay of these nuclei is expected due to Gamow-Teller transitions above the neutron separation energy of the daughter nucleus. An experiment for measuring the strength distribution in the 78Ni region (27≤Z≤33) was performed at the RIBF facility at RIKEN Nishina Center, JAPAN using a YSO-based implantation detector [1] and VANDLE [2] array for Time-of-Flight-based spectroscopy of the β-delayed neutrons. For γ-ray detection, two HPGe clovers and 10 LaBr3  detectors were used. This contribution presents the first results on the β-decay feeding to neutron-unbound states in the decay of  79,80,81Cu. For 79Cu decay, we identified neutrons in the energy range ~ 0.3-2.3 MeV, emitted from neutron-unbound states in 79Zn. We also identified neutrons in coincidence with the 2+→0+ transition of 730 keV to the ground state in 78Zn, needed to ascertain the excitation energy for strength distribution. For 80,81Cu (N = 51,52), we report on the first measurement of the β-delayed neutron spectra. These measurements will highlight the impact of the N=50 shell-closure on β-decay.

*The present experiment was carried out at the RI Beam Factory operated by RIKEN Nishina Center, RIKEN and CNS, University of Tokyo. This research was sponsored in part by the Office of Nuclear Funding Acknowledgement: Physics, U.S. Department of Energy Ander Award No. DE-FG02-96ER40983 (UTK) and DE-AC05-00OR22725 (ORNL), and by the National Nuclear Security Administration under the Stewardship Science Academic Alliances program through DOE Award No. DE-NA0002132 and DE-NA0002934.

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Publication: 1. R. Yokoyama et al., Nucl. Instrum. Methods Phys. A 937, 93 (2019).
2. W.A. Peters et al., Nucl. Instrum. Methods Phys. A 836, 122 (2016).

Presenters

  • Maninder Singh

    • University of Tennessee

Authors

  • Maninder Singh

    • University of Tennessee

  • Rin Yokoyama

    • University of Tennessee

  • Robert Grzywacz

    • University of Tennessee
    • University of Tennessee and Oak Ridge National Lab
    • University of Tennessee, Knoxville

  • Thomas T King

    • University of Tennessee
    • Oak Ridge National Laboratory
    • Oak Ridge National Lab

  • Shunji Nishimura

    • RIKEN Nishina Center
    • RIKEN Nishina Center, Japan

  • Jeremy Bundgaard

    • University of Tennessee

  • Pierre Brionnet

    • RIKEN Nishina Center

  • Nathan Brewer

    • Oak Ridge Natl. Lab
    • Oak Ridge national laboratory
    • ORNL
    • Oak Ridge National Laboratory

  • Ian C Cox

    • University of Tennessee

  • Aleksandra Fijalkowska

    • Rutgers University
    • University of Warsaw

  • Luis M Fraile

    • Universidad Complutense de Madrid

  • Shintaro Go

    • Kyushu University
    • RIKEN Nishina Center, Japan

  • Andrea Gottardo

    • INFN

  • Marek Karny

    • University of Warsaw, Poland
    • University of Warsaw

  • Andrew M Keeler

    • University of Tennessee

  • Agnieszka Korgul

    • University of Warsaw, Poland
    • University of Warsaw

  • Miguel Madurga

    • University of Tennessee
    • University of Tennessee, Knoxville

  • Krzysztof Miernik

    • University of Warsaw, Poland
    • University of Warsaw

  • Shree K Neupane

    • University of Tennessee
    • University of Tennessee, Knoxville

  • Megumi NIIKURA

    • University of Tokyo

  • Shimizu Noritaka

    • University of Tokyo

  • Marek Pfützner

    • University of Warsaw

  • Monika Piersa

    • University of Warsaw, Poland
    • University of Warsaw

  • Mustafa M Rajabali

    • Tennessee Tech University
    • Tennessee Technological University

  • Bertis C Rasco

    • Oak Ridge National Laboratory
    • Oak Ridge National Lab
    • ORNL

  • Krzysztof Rykaczewski

    • Oak Ridge National Laboratory
    • ORNL

  • Michal Silkowski

    • University of Warsaw

  • michal Stepaniuk

    • University of Warsaw

  • Jose L Tain

    • Instituto de Fisica Corpuscular, Valencia, Spain
    • Instituto de Física Corpuscular

  • Alvaro Tolosa-Delgado

    • University of Valencia

  • Zhengyu Xu

    • University of Tennessee
    • University of Tennessee, Knoxville

  • Marzena Wolinska-Cinhocka

    • Heavy Ion Laboratory University of Warsaw, Poland
    • Heavy Ion Laboratory, University of Warsaw
    • Heavy Ion Laboratory, University of Warsaw, Poland