https://doi.org/10.1051/epjconf/201714610009
Isomer-delayed gamma-ray spectroscopy of neutron-rich 166Tb
1 Department of Physics, University of Surrey, Guildford GU2 7XH, UK
2 National Physical Laboratory, Teddington, 11 0LW, UK
3 RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
4 International Research Center for Nuclei and Particles in the Cosmos, Beihang University, Beijing 100191, China
5 School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, China
6 Department of Physics, the University of Hong Kong, Pokfulam Road, Hong Kong
7 KU Leuven, Instituut voor Kern- en Stralings fysica, 3001 Leuven, Belgium
8 Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
9 Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578, Japan
10 School of Computing, Engineering and Mathematics, University of Brighton, BN2 4JG, UK
11 Department of Nuclear Physics, R.S.P.E., Australian National University, Canberra, A.C.T.02000, Australia
12 Nuclear Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
13 Department of Physics, Osaka University, Machikaneyama-machi 1-1, Osaka 560-0043, Toyonaka, Japan
14 School of Physics, Peking University, Beijing 100871, China
15 Department of Applied Physics, School of Science, Xi’an Jiaotong University, China
16 Institute for Nuclear Research, Hungarian Academy of Sciences, PO Box 51, Debrecen, Hungary
17 Department of Physics, Chung-Ang University, Seoul 156-756, Republic of Korea
18 NU Hanoi University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam
19 Department of Physics, College of Science in Zulfi, Almajmaah University, PO Box 1712, 11932, Saudi Arabia
20 Department of Physics, Sungkyunkwan University, Suwon 440-746, Republic of Korea
21 School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, UK
22 Department of Physics, Central Michigan University, Mount Pleasant, Michigan 48859, USA
23 Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047, Japan
24 GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
25 Hoseo University, Asan, Chungnam 336-795, Korea
26 Horia Hulubei National Institute of Physics and Nuclear Engineering,(IFIN-HH), 077125 Bucharest, Romania
27 School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
28 Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro, Italy
a e-mail: l.a.gurgi@surrey.ac.uk
Published online: 13 September 2017
This short paper presents the identification of a metastable, isomeric-state decay in the neutron-rich odd-odd, prolate-deformed nucleus 166Tb. The nucleus of interest was formed using the in-flight fission of a 345 MeV per nucleon 238U primary beam at the RIBF facility, RIKEN, Japan. Gamma-ray transitions decaying from the observed isomeric states in 166Tb were identified using the EURICA gamma-ray spectrometer, positioned at the final focus of the BigRIPS fragments separator. The current work identifies a single discrete gamma-ray transition of energy 119 keV which de-excites an isomeric state in 166Tb with a measured half-life of 3.5(4) μs. The multipolarity assignment for this transition is an electric dipole and is made on the basis internal conversion and decay lifetime arguments. Possible two quasi-particle Nilsson configurations for the initial and final states which are linked by this transition in 166Tb are made on the basis of comparison with Blocked BCS Nilsson calculations, with the predicted ground state configuration for this nucleus arising from the coupling of the v(1-/2)[521] and π(3+/2) Nilsson orbitals.
© The Authors, published by EDP Sciences, 2017
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