Eur. Phys. J. A 11, 9-13 (2001)

A new s isomer in ¹³⁶Sb produced in the projectile fission of ²³⁸U

M.N. Mineva¹, M. Hellström^{1, 2}, M. Bernas³, J. Gerl², H. Grawe², M. Pfützner⁴, P.H. Regan⁵, M. Rejmund⁶, D. Rudolph¹, F. Becker⁶, C.R. Bingham⁷, T. Enqvist⁸, B. Fogelberg⁹, H. Gausemel¹⁰, H. Geissel², J. Genevey¹¹, M. Górska², R. Grzywacz⁷, K. Hauschild⁶, Z. Janas⁴, I. Kojouharov², Y. Kopatch², A. Korgul⁴, W. Korten⁶, J. Kurcewicz⁴, M. Lewitowicz¹², R. Lucas⁶, H. Mach⁹, S. Mandal², P. Mayet², C. Mazzocchi^{2, 13}, J.A. Pinston¹¹, Zs. Podolyàk⁵, H. Schaffner², Ch. Schlegel², K. Schmidt², K. Sümmerer² and H.J. Wollersheim<sup>2

1</sup>  Division of Cosmic and Subatomic Physics, Lund University, SE-22100 Lund, Sweden
²  Gesellschaft für Schwerionenforschung mbH, D-64291 Darmstadt, Germany
³  Institut de Physique Nucléaire d'Orsay, IN2P3-CNRS, F-91406 Orsay Cedex, France
⁴  Institute of Experimental Physics, Warsaw University, PL-00861, Poland
⁵  Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom
⁶  CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette Cedex, France
⁷  Department of Physics, University of Tennessee, Knoxville, TN 37996, USA
⁸  Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
⁹  Department of Radiation Science, Uppsala University, S-61182 Nyköping, Sweden
¹⁰  Department of Chemistry, University of Oslo, Blindern, N-0315 Oslo, Norway
¹¹  Institut des Sciences Nucléaires, IN2P3-CNRS/Université Joseph Fourier, F-38026 Grenoble Cedex, France
¹²  Grand Accélérateur National d'Ions Lourds, BP 5027, F-14021 Caen Cedex, France
¹³  Università degli Studi di Milano, I-20133 Milano, Italy

Milena.Mineva@kosufy.lu.se

(Received: 23 April 2001 Communicated by D. Schwalm )

Abstract
The neutron-rich isotope ¹³⁶Sb has been produced following the relativistic projectile fission of ²³⁸U in an experiment performed at the Fragment Separator at GSI, Darmstadt. Delayed -ray spectroscopy of the fission products has been performed after isotope separation. A new isomeric state in ¹³⁶Sb has been populated, and its lifetime measured as T_1/2=565 (50) ns. Realistic and empirical shell-model calculations have been performed and are compared to the experimental observables.

PACS
21.10.Tg - Lifetimes.
21.60.Cs - Shell model.
25.75.-q - Relativistic heavy-ion collisions.

© Società Italiana di Fisica, Springer-Verlag 2001