Speaker
Description
S. Alhomaidhi$^{\mathrm{1,2}}$, V. Werner$^{\mathrm{1,2}}$, P.-A. Söderström$^{\mathrm{1,12}}$, P. R. John$^{\mathrm{1}}$, U. Ahmed$^{\mathrm{1}}$, H. M. Albers$^{\mathrm{2}}$, C. Appleton$^{\mathrm{6}}$, T. Arıcı$^{\mathrm{2}}$, M. Armstrong$^{\mathrm{2,4}}$, A. Banerjee$^{\mathrm{2}}$, J. Benito$^{\mathrm{11}}$, A. Blazhev$^{\mathrm{4}}$, P. Boutachkov$^{\mathrm{2}}$, A. Bozo$^{\mathrm{5}}$, A. M. Bruce$^{\mathrm{10}}$, M. M. Chishti$^{\mathrm{3}}$, S. M. Collins$^{\mathrm{5}}$, T. Davinson$^{\mathrm{6}}$, T. Dickel$^{\mathrm{2}}$, A. Esmaylzadeh$^{\mathrm{4}}$, L. M. Fraile$^{\mathrm{11}}$, J. Gerl$^{\mathrm{2}}$, M. Górska$^{\mathrm{2}}$, J. Ha$^{\mathrm{9}}$, E. Haettner$^{\mathrm{2}}$, O. Hall$^{\mathrm{6}}$, H. Heggen$^{\mathrm{2}}$, N. Hubbard$^{\mathrm{1,2}}$, S. Jazrawi$^{\mathrm{3}}$, J. Jolie$^{\mathrm{4}}$, R. Kern$^{\mathrm{1}}$, L. Knafla$^{\mathrm{4}}$, I. Kojouharov$^{\mathrm{2}}$, N. Kurz$^{\mathrm{2}}$, A. K. Mistry$^{\mathrm{2}}$, J. R. Murias$^{\mathrm{11}}$, N. Pietralla$^{\mathrm{1}}$, Zs. Podolyak$^{\mathrm{3}}$, M. Polettini$^{\mathrm{7,8}}$, F. Recchia$^{\mathrm{9}}$, P. H. Regan$^{\mathrm{3}}$, J.-M. Régis$^{\mathrm{4}}$, M. Rudigier$^{\mathrm{1}}$, E. Sahin$^{\mathrm{1,2}}$, V. Sánchez-Tembleque$^{\mathrm{11}}$, H. Schaffner$^{\mathrm{2}}$, L. Sexton$^{\mathrm{6}}$, A. Sharma$^{\mathrm{2}}$, Ch. Scheidenberger$^{\mathrm{2}}$, R. Shearman$^{\mathrm{5}}$, J. M. Udías$^{\mathrm{11}}$, J. Wiederhold$^{\mathrm{1}}$, P. Woods$^{\mathrm{6}}$, A. Yaneva$^{\mathrm{2,4}}$, R. Zidarova$^{\mathrm{1}}$ on behalf of DESPEC collaboration
1 Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
2 GSI Helmholzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
3 Department of Physics, University of Surrey, Guildford, GU2 7XH, UK
4 Institut für Kernphysik, Universität zu Köln, 50937 Köln, Germany
5 National Physical Laboratory, Teddington, Middlesex TW11 0LW, UK
6 School of Physics and Astronomy, University of Edinburgh, EH9 3FD Edinburgh, UK
7 Universita degli Studi di Milano, Via Celoria 16, 20133, Milano, Italy
8 INFN, sez. di Milano, Via Celoria 16, 20133, Milano, Italy
9 Dipartimento di Fisica e Astronomia dell'Universita di Padova and INFN Padova, 35131, Padova, Italy
10 School of Computing, Engineering, and Mathematics, University of Brighton, Brighton BN2 4GJ, UK
11 Grupo de Fisica Nuclear, FAMN, Universidad Complutense, CEI Moncloa, 28040 Madrid, Spain
12 Extreme Light Infrastructure - Nuclear Physics (ELI-NP), Magurele 077126, Romania
In March 2021, the DEcay SPECtroscopy (DESPEC) experiment S452 was performed at GSI Helmholtzzentrum für Schwerionenforschung. The focus of the experiment was to measure the lifetimes and energies of the first exited states of neutron-rich Os, W and Hf isotopes in the A~190 mass region, in search for prolate-oblate shape transition [1]. The experimental setting, which was centered on $^{\mathrm{190}}$Ta, allowed us to investigate the single-particle structures of isomers in this region and connect their decays to the shape evolution.
The isomeric state for the nucleus of interest, $^{\mathrm{189}}$Ta, was populated by the fragmentation of $^{\mathrm{208}}$Pb primary beam impinging on $^{\mathrm{9}}$Be target [2]. The cocktail beam was separated and identified using FRagment Separator (FRS) [3] to implant the nuclei of interest in the active stopper, Advance Implantation Detector Array (AIDA). The AIDA consist of 3 Double Sided Silicon Strip Detectors (DSSSDs) [4] and located in the final focal plan of the FRS. The gamma rays from the implanted ions were detected by thirty six LaBr$_{\text{3}}$(Ce) detectors the Fast TIMing Array (FATIMA) [5] and two cluster HPGe detectors, 7 crystal each (EUROBALL), surrounding the AIDA. The LaBr$_{\text{3}}$(Ce) detectors were used for fast-timing spectroscopy, while HPGe provides precise energy information.
Data obtained in this experiment is analyzed on an event-by-event basis, for which the analysis is in progress. An overview of the DESPEC setup, the analysis procedures regarding this experiment and a preliminary result of the isomeric lifetime measurement of $^{\mathrm{189}}$Ta will be presented in the conference.
[1] R. F. Casten, Progress in Particle and Nuclear Physics 62, 183 (2009).
[2] T. Brock et al., Phys. Rev. C 82, 061309 (2011).
[3] S. Pietri et al., Nucl. Instrum. Meth. Phys. Res. A 261 (2007) 1079.
[4] "AIDA TDR, " [Online]. Available: https://fair-center.de/fileadmin/fair/experiments/
HISPEC_DESPEC/documents/TDR_HISPEC_DESPEC_AIDA_public.pdf
[5] "FATIMA TDR, " [Online]. Available: https://fair-center.de/fileadmin/fair/experiments/
HISPEC_DESPEC/documents/TDR_HISPEC_DESPEC_FATIMA_public.pdf
