Bonn 2010 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 1: Eröffnung und Hauptvorträge I

HK 1.2: Hauptvortrag

Montag, 15. März 2010, 09:30–10:00, HG X

Probing the isospin structure of short-lived excited nuclear states using the Transient Field technique — •Joerg Leske¹, Norbert Pietralla¹, Thorsten Kröll¹, Andrea Jungclaus², and Karl-Heinz Speidel³ — ¹IKP, TU Darmstadt, D-64289 Darmstadt — ²Instituto de Estructura de la Materia, CSIC, E-28006 Madrid, Spain — ³HISKP, Universität Bonn, D-53115 Bonn

In the vicinity of the Z=50 and N=82 shell closures unexpected findings in the behaviour of the electric quadrupole transition probabilities of excited nuclear states, e.g. the surplus of B(E2) strengths in neutron deficient Sn isotopes or the surprisingly small B(E2,0₁⁺→2₁⁺) in ¹³⁶Te[1], have triggered many theoretical investigations and further experiments. However, model predictions could only partially explain the observed behaviour and the isospin structure of the excitations in the nuclear valence shell is discussed controversially, e.g. in ¹³⁶Te where results from calculations differ significantly. Due to their single-particle nature magnetic dipole moments grant access to the missing experimental information and we have therefore measured g factors of the first excited states in relevant even Sn, Te, Xe and Ba isotopes in stable and radioactive beam experiments. The short lifetimes in the range of a few ps are experimentally challenging and solely the technique of Transient Magnetic Fields can be applied. Achievements and results will be discussed together with a presentation of experimental aspects and developments for the use of this technique with radioactive ion beams at low- and intermediate beam energies. *supported by the BMBF
(1) D.C. Radford et al., PRL 88, (2002),222501