Observation of a γ-decaying millisecond isomeric state in 128Cd80

A Jungclaus,R Orlandi,N Kurz,S Bönig,A Gargano,L Coraggio,Zs Podolyák,I Kojouharov,K Moschner,H Grawe,Zs Vajta,G Benzoni,H Schaffner,D Mücher,A Gadea,F Browne,F Drouet,A Montaner-Pizá,P Doornenbal,D Kameda,S Ilieva,F Naqvi,A Odahara,H Watanabe,J Wu,Hiroyuki Takeda ,T Sumikama,Z Li,K Yoshinaga,Z Patel,N Fukuda,N Inabe,G J Lane ,Thilo Kroll ,Hiroshi Suzuki ,N Itaco,J M Daugas ,H Sakuraï ,J Taprogge,Z Y Xu ,P.-A Söderström,Y K Kwon ,T Kubo,A Wendt,G S Simpson ,T Isobe,F G Kondev ,K Y Chae ,G Gey,A Yagi,G Lorusso,G.D Kim,M Nııkura ,H Baba,Y.-K Kim,H S Jung ,R Gernhäuser,Katja Steiger ,Y Shimizu,S Nishimura,H Nıshıbata

doi:10.1016/j.physletb.2017.07.006

Abstract

A new high-spin isomer in the neutron-rich nucleus 128Cd was populated in the projectile fission of a 238U beam at the Radioactive Isotope Beam Factory at RIKEN. A half-life of T1/2=6.3(8) ms was measured for the new state which was tentatively assigned a spin/parity of (15−). The experimental results are compared to shell model calculations performed using state-of-the-art realistic effective interactions and to the neighbouring nucleus 129Cd. In the present experiment no evidence was found for the decay of a 18+E6 spin-trap isomer, based on the complete alignment of the two-neutron and two-proton holes in the 0h11/2 and the 0g9/2 orbit, respectively, which is predicted to exist by the shell model.

Highlights

A new high-spin isomer in the neutron-rich nucleus 128Cd was populated in the projectile fission of a 238U beam at the Radioactive Isotope Beam Factory at RIKEN
In the present experiment no evidence was found for the decay of a 18+ E6 spin-trap isomer, based on the complete alignment of the two-neutron and two-proton holes in the 0h11/2 and the 0g9/2 orbit, respectively, which is predicted to exist by the shell model
The experiment was performed at the Radioactive Isotope Beam Factory (RIBF) of the RIKEN Nishina Center within the EURICA campaign

Summary

Introduction

A new high-spin isomer in the neutron-rich nucleus 128Cd was populated in the projectile fission of a 238U beam at the Radioactive Isotope Beam Factory at RIKEN.

Results

Conclusion