Frankfurt 2014 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 10: Struktur und Dynamik von Kernen

HK 10.7: Talk

Monday, March 17, 2014, 18:30–18:45, HZ 4

Investigation of low-lying dipole strength in ¹²⁴Sn — •D. Symochko¹, T. Aumann¹, M. Bhike², V. Derya.³, M. Duchêne¹, J. Isaak⁴, J. Kelley², M. Knörzer¹, B. Löher⁴, N. Pietralla¹, D. Savran⁴, H. Scheit¹, A. Tonchev⁵, W. Tornow², V. Werner^1,6, and A. Zilges³ — ¹Institut für Kernphysik, Technische Universität Darmstadt, Germany — ²Department for Physics, Duke University, USA — ³Institut für Kernphysik, Universität zu Köln, Germany — ⁴ExtreMe Matter Institute EMMI and Research Division, Darmstadt, Germany — ⁵Lawrence Livermore National Laboratory, USA — ⁶WNSL, Yale University, USA

Dipole excitations in the semi-magic ¹²⁴Sn nucleus were studied in (γ,γ’) reactions using the γ³ - high-efficiency detector setup [1]. The experiment was carried out with quasimonoenergetic photon beams provided by the HIγS facility at the TUNL in the energy range from 5.2 to 8.6 MeV at 15 different energies. Measurements allowed to identify near 80 new transitions to the ground state, obtain reduced transition probabilities and assign parity quantum numbers to the observed excited states. Besides, the γ-γ coincidence technique gave access to the γ-decay pattern of the Pygmy Dipole Resonance, e.g. it was possible to analyse the branching ratios to the first excited 2+ state. Investigations were made as a part of the experimental campaign aimed to obtain a complete picture of dipole strength function evolution in Sn isotopes - from stable ¹¹²Sn to short-lived ¹³⁴Sn.

Supported by DFG (SFB 634 and ZI 510/4-2).

1. B. Löher et al. Nucl. Instr. Meth. 723, P. 136 (2013).