Bochum 2018 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 24: Structure and Dynamics of Nuclei IV
HK 24.6: Vortrag
Dienstag, 27. Februar 2018, 18:00–18:15, HZO 70
Prompt and delayed gamma-spectroscopy of neutron-rich krypton isotopes with N ≤ 60* — •Rosa-Belle Gerst, Kevin Moschner, and Andrey Blazhev — Institut für Kernphysik, Universität zu Köln
Low-lying excited states of the neutron-rich 94,95,96Kr were measured at the RIBF at the RIKEN Nishina Center for Accelerator-Based Science as part of the SEASTAR campaign. The nuclei of interest were populated in nucleon knockout reactions using the MINOS device surrounded by the DALI2 array for prompt γ-spectroscopy. Additionally, the EURICA array was run in a parasitic mode to measure the delayed isomeric transitions in 95Kr. In all three nuclei, previously unknown γ-transitions were observed. Even-even Sr and Zr nuclei in the A = 100 region show a sudden onset of deformation at N = 60 while the lighter isotopes up to N = 58 are rather spherical. Contrarily, the even krypton isotopes exhibit a smooth onset of collectivity up to N = 60 [1]. For 96Kr, the measured new transitions imply the existence of low-lying low-spin non-yrast states, which we interpret as the shape coexisting states becoming yrast above N = 60 [2] in agreement with very recent IBM calculations [3]. For 95Kr, the analysis of prompt γ-radiation with and without coincidence of delayed radiation identified the prompt γ-rays as either feeding or bypassing the known isomeric state in 95Kr.
*Supported by the DFG under Grant No. BL 1513/1-1
[1] M. Albers et al., Phys. Rev. Lett. 108, 062701 (2012)
[2] F. Flavigny et al., Phys. Rev. Lett. 118, 242501 (2017)
[3] K.Nomura et al., Phys. Rev. C 96, 034310 (2017)