Eur. Phys. J. A (2009) 42: 489-493
https://doi.org/10.1140/epja/i2009-10794-5

Regular Article - Experimental Physics

Structure of neutron-rich nuclei around the N = 126 closed shell; the yrast structure of ²⁰⁵Au₁₂₆ up to spin-parity = (19/2⁺)

¹ Department of Physics, University of Surrey, GU2 7XH, Guildford, UK
² GSI, Planckstrasse 1, D-64291, Darmstadt, Germany
³ Department of Physics, Lund University, S-22100, Lund, Sweden
⁴ WNSL, Yale University, 272 Whitney Avenue, 06520, New Haven, CT, USA
⁵ The Institute of Nuclear Physics, PL-31-342, Kraków, Poland
⁶ Department of Physics, University of the West of Scotland, PA1 2BE, Paisley, Scotland
⁷ Departmento de Fisica Teórica, Universidad Autonoma de Madrid, Madrid, Spain
⁸ IKP, Universität zu Köln, D-50937, Köln, Germany
⁹ Universidad de Santiago de Compostela, Santiago de Campostela, Spain
¹⁰ INFN, Università degli Studi di Milano, I-20133, Milano, Italy
¹¹ IEP, Warsaw University, Hoża 69, PL-00-681, Warsaw, Poland
¹² INRNE, Bulgarian Academy of Sciences, BG-1784, Sofia, Bulgaria
¹³ NSCL, Michigan State University, 48824-1321, East Lansing, MI, USA
¹⁴ School of Environment and Technology, University of Brighton, BN2 4GJ, Brighton, UK
¹⁵ Institute for Nuclear Research, H-4001, Debrecen, Hungary
¹⁶ Instituto de Fisica Corpuscular, Valencia, Spain
¹⁷ Nuclear Engineering Division, Argonne National Laboratory, 60439, Argonne, IL, USA
¹⁸ Physik Department E12, Technische Universität München, Garching, Germany
¹⁹ Japan Atomic Energy Agency, 619-0215, Kyoto, Japan

^* e-mail: Z.Podolyak@surrey.ac.uk

Received: 31 December 2008
Revised: 1 April 2009
Accepted: 9 April 2009
Published online: 17 May 2009

Abstract

Heavy neutron-rich nuclei have been populated through the relativistic fragmentation of a beam at GeV on a thick Be target. The synthesised nuclei were selected and identified in-flight using the fragment separator at GSI. Approximately 300 ns after production, the selected nuclei were implanted in an mm thick perspex stopper, positioned at the centre of the RISING -ray detector spectrometer array. A previously unreported isomer with a half-life ns has been observed in the N = 126 closed-shell nucleus . Through -ray singles and - coincidence analysis a level scheme was established. The comparison with a shell model calculation tentatively identifies the spin-parity of the excited states, including the isomer itself, which is found to be .