Tübingen 2003 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 7: Kern- und Teilchen-Astrophysik I

HK 7.11: Vortrag

Montag, 17. März 2003, 18:45–19:00, F

First β- and γ-Spectroscopic Studies of the r-Process Nuclide ¹³⁰Cd — •Iris Dillmann¹, Karl-Ludwig Kratz¹, and Andreas Wöhr² — ¹Institut für Kernchemie, Universität Mainz, Mainz — ²Department of Chemistry, University of Maryland, USA

Using a combination of the RILIS and neutron-converter systems at CERN-ISOLDE, we have performed first β- and γ-spectroscopic measurements of the 162-ms isotope ¹³⁰Cd₈₂. This neutron-magic nuclide represents one of the most important classical r-process ”waiting-points”. So far 12 new γ-lines of ¹³⁰Cd decay, their γγ- and βγ- coincidence relationships were observed. The most surprising result is the position of the [πg_9/2⊗νg_7/2] 1⁺ state at 2.12 MeV, which is considerably higher than predicted by recent shell-model calculations. This excitation energy corresponds with a rather high Q_β value of about 8 MeV obtained from β-endpoint measurements, thus leading to a physically consistent picture of ¹³⁰Cd β-decay. With this new information, we have improved local shell-model predictions of so far unknown N≃82 nuclei and have tested their implications on the formation of the solar-system r-abundance peak at A≃130.