β-decay spectroscopy of neutron-rich ^160,161,162Sm isotopes

¹ Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom
² RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
³ National Physical Laboratory, Teddington, Middlesex, TW11 0LW, United Kingdom
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 Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047, Japan
⁷ Department of Physics, Osaka University, Machikaneyama-machi 1-1, Osaka 560-0043 Toyonaka, Japan
⁸ LPSC, Université Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut National Polytechnique de Grenoble, F-38026 Grenoble Cedex, France
⁹ School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
¹⁰ School of Computing, Engineering and Mathematics, University of Brighton, Brighton, BN2 4JG, United Kingdom
¹¹ Department of Physics, University of York, Heslington, York, YO10 5DD, United Kingdom
¹² Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578, Japan
¹³ Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
¹⁴ Department of Physics, University of Oslo, Oslo, Norway
¹⁵ INFN Sezione di Milano, I-20133 Milano, Italy
¹⁶ Center for Nuclear Study (CNS), University of Tokyo, Wako, Saitama 351-0198, Japan
¹⁷ Instituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro, Italy
¹⁸ Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
¹⁹ Research Facility Center for Pure and Applied Science, University of Tsukuba, Ibaraki 305-8577, Japan
²⁰ Rare Isotope Science Project, Institute for Basic Science, Daejeon 305-811, Korea
²¹ GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
²² Institute for Nuclear Research, Hungarian Academy of Sciences, P. O. Box 51, Debrecen, H-4001, Hungary
²³ School of Physics, Peking University, Beijing 100871, China
²⁴ Hoseo University, Asan, Chungnam 336-795, Korea
²⁵ Instituto de Estructura de la Materia, CSIC, E-28006 Madrid, Spain
²⁶ Departamento de Física Teórica, Universidad Autónoma de Madrid, E-28049 Madrid, Spain

^a e-mail: z.patel@surrey.ac.uk

Published online: 5 September 2016

Abstract

Neutron-rich ^160,161,162Sm isotopes have been populated at the RIBF, RIKEN via β first time. β-coincident γ rays were observed in all three isotopes including γ rays from the isomeric decay of ¹⁶⁰Sm and ¹⁶²Sm. The isomers in ¹⁶⁰Sm and ¹⁶²Sm have previously been observed but have been populated via β decay for the first time. The isomeric state in ¹⁶²Sm is assigned a $$4^{-}v{\frac{7}{2}}^{+}\left[633\right]\otimes v{\frac{1}{2}}^{-}\left[521\right]$$ configuration based on the decay pattern. The level schemes of ¹⁶⁰Sm and ¹⁶²Sm are presented. The ground states in the parent nuclei ¹⁶⁰Pm and ¹⁶²Pm are both assigned a $$6^{-}v{\frac{7}{2}}^{+}\left[633\right]\otimes \pi {\frac{5}{2}}^{-}\left[532\right]$$ configuration based on the population of states in the daughter nuclei. Blocked BCS calculations were performed to further investigate the spin-parities of the ground states in ¹⁶⁰Pm, ¹⁶¹Pm, and ¹⁶²Pm, and the isomeric state in ¹⁶²Sm