Berlin 2005 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 23: Hauptvortr
äge

HK 23.1: Hauptvortrag

Dienstag, 8. März 2005, 10:15–10:45, TU MA001

Investigation of triple shape coexistence in ^188,186Pb using transition probabilities — •A. Dewald¹, O. Möller¹, B. Melon¹, B. Saha¹, K.O. Zell¹, T. Pissulla¹, S. Christen¹, J. Jolie¹, T. Grahn², P. Greenlees², S. Eeckhaudt², P. Jones², R. Julin², M. Leino², J. Pakarinen², P. Rahkila², C. Scholey², J. Uusitalo², P. Petkov³, R. Krücken⁴, T. Kröll⁴, P. Maierbeck⁴, C.W. Beausang⁵, D.A. Meyer⁵, W. Korten⁶, A. Görgen⁶, and Y.Le Coz⁶ — ¹IKP, Universität zu Köln, Köln — ²University of Jyväskylä, Finland — ³INRE, Sofia, Bulgaria — ⁴E12, TU München, München — ⁵WNSL, Yale University, USA — ⁶Dapnia/SPhN, CEA Saclay, France

The phenomenon of triple shape coexistence, established in the neutron deficient lead isotopes, is still one of the most exciting topics in nuclear structure physics. Despite of large theoretical and experimental effort devoted to that interesting phenomenon the knowledge on absolute transition probabilities in the nuclei of interest is very limited. Therefore we performed two recoil distance lifetime measurements using the ^106,108Pd(⁸³Kr,3n)^186,188Pb reactions at the JYFL Jyväskylä. The Köln plunger device was employed with the JUROGAM spectrometer and the gas-filled separator RITU. For ¹⁸⁸Pb recoil gated γ spectra were used to separate the weak reaction channel from a dominant fission. We determined four lifetimes from which the deformation of the prolate band was experimentally deduced for the first time. In case of ¹⁸⁶Pb α-tagging was applied for the first time in combination with a plunger measurement. First results will be presented. Supported in part by BMBF No. 06K167 and the EU-FP5 projects HPRI-1999-CT-50017 and HPRI-CT-1999-00044.