Isomer decay spectroscopy of 164Sm and 166Gd: midshell collectivity around N=100

Z Patel; P-A Söderström; Zs Podolyák; P H Regan; P M Walker; H Watanabe; E Ideguchi; G S Simpson; H L Liu; S Nishimura; Q Wu; F R Xu; F Browne; P Doornenbal; G Lorusso; S Rice; L Sinclair; T Sumikama; J Wu; Z Y Xu; N Aoi; H Baba; F L Bello Garrote; G Benzoni; R Daido; Y Fang; N Fukuda; G Gey; S Go; A Gottardo; N Inabe; T Isobe; D Kameda; K Kobayashi; M Kobayashi; T Komatsubara; I Kojouharov; T Kubo; N Kurz; I Kuti; Z Li; M Matsushita; S Michimasa; C-B Moon; H Nishibata; I Nishizuka; A Odahara; E Şahin; H Sakurai; H Schaffner; H Suzuki; H Takeda; M Tanaka; J Taprogge; Zs Vajta; A Yagi; R Yokoyama

doi:10.1103/PhysRevLett.113.262502

Isomer decay spectroscopy of 164Sm and 166Gd: midshell collectivity around N=100

Phys Rev Lett. 2014 Dec 31;113(26):262502. doi: 10.1103/PhysRevLett.113.262502. Epub 2014 Dec 22.

Authors

Z Patel¹, P-A Söderström², Zs Podolyák³, P H Regan⁴, P M Walker³, H Watanabe⁵, E Ideguchi⁶, G S Simpson⁷, H L Liu⁸, S Nishimura², Q Wu⁹, F R Xu⁹, F Browne¹⁰, P Doornenbal², G Lorusso², S Rice¹, L Sinclair¹¹, T Sumikama¹², J Wu¹³, Z Y Xu¹⁴, N Aoi⁶, H Baba², F L Bello Garrote¹⁵, G Benzoni¹⁶, R Daido¹⁷, Y Fang¹⁷, N Fukuda², G Gey⁷, S Go¹⁸, A Gottardo¹⁹, N Inabe², T Isobe², D Kameda², K Kobayashi²⁰, M Kobayashi¹⁸, T Komatsubara²¹, I Kojouharov²², T Kubo², N Kurz²², I Kuti²³, Z Li²⁴, M Matsushita¹⁸, S Michimasa¹⁸, C-B Moon²⁵, H Nishibata¹⁷, I Nishizuka¹², A Odahara¹⁷, E Şahin¹⁵, H Sakurai²⁶, H Schaffner²², H Suzuki², H Takeda², M Tanaka¹⁷, J Taprogge²⁷, Zs Vajta²³, A Yagi¹⁷, R Yokoyama²⁸

Affiliations

¹ Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom and RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
² RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
³ Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom.
⁴ Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom and National Physical Laboratory, Teddington, Middlesex TW11 0LW, United Kingdom.
⁵ RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan and International Research Center for Nuclei and Particles in the Cosmos, Beihang University, Beijing 100191, China and 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 and Department of Physics, Osaka University, Machikaneyama-machi 1-1, Osaka 560-0043 Toyonaka, Japan.
⁷ LPSC, Université Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut National Polytechnique de Grenoble, F-38026 Grenoble Cedex, France.
⁸ Department of Applied Physics, School of Science, Xi'an Jiaotong University, Xi'an 710049, China.
⁹ School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China.
¹⁰ RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan and School of Computing, Engineering and Mathematics, University of Brighton, Brighton, BN2 4JG, United Kingdom.
¹¹ RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan and 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 RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan and School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China.
¹⁴ Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
¹⁵ Department of Physics, University of Oslo, Oslo, Norway.
¹⁶ INFN Sezione di Milano, I-20133 Milano, Italy.
¹⁷ Department of Physics, Osaka University, Machikaneyama-machi 1-1, Osaka 560-0043 Toyonaka, Japan.
¹⁸ Center for Nuclear Study (CNS), University of Tokyo, Wako, Saitama 351-0198, Japan.
¹⁹ Instituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro I-35020 Legnaro, Italy.
²⁰ Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan.
²¹ Research Facility Center for Pure and Applied Science, University of Tsukuba, Ibaraki 305-8577, Japan and Rare Isotope Science Project, Institute for Basic Science, Daejeon 305-811, Korea.
²² GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany.
²³ Institute for Nuclear Research, Hungarian Academy of Sciences, P. O. Box 51, Debrecen H-4001, Hungary.
²⁴ School of Physics, Peking University, Beijing 100871, China.
²⁵ Hoseo University, Asan, Chungnam 336-795, Korea.
²⁶ RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan and Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
²⁷ Instituto de Estructura de la Materia, CSIC, E-28006 Madrid, Spain and Departamento de Física Teórica, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
²⁸ Center for Nuclear Study (CNS), University of Tokyo, Wako-shi, Saitama 351-0198, Japan.

PMID: 25615314
DOI: 10.1103/PhysRevLett.113.262502

Abstract

Excited states in the N=102 isotones 166Gd and 164Sm have been observed following isomeric decay for the first time at RIBF, RIKEN. The half-lives of the isomeric states have been measured to be 950(60) and 600(140) ns for 166Gd and 164Sm, respectively. Based on the decay patterns and potential energy surface calculations, including β6 deformation, a spin and parity of 6- has been assigned to the isomeric states in both nuclei. Collective observables are discussed in light of the systematics of the region, giving insight into nuclear shape evolution. The decrease in the ground-band energies of 166Gd and 164Sm (N=102) compared to 164Gd and 162Sm (N=100), respectively, presents evidence for the predicted deformed shell closure at N=100.