Bochum 2018 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 48: Structure and Dynamics of Nuclei IX

HK 48.6: Vortrag

Donnerstag, 1. März 2018, 15:15–15:30, HZO 70

Lifetime measurements in the vicinity of doubly-magic ⁵⁶Ni — •K. Arnswald, P. Reiter, A. Blazhev, T. Braunroth, A. Dewald, M. Droste, C. Fransen, C. Müller-Gatermann, A. Goldkuhle, R. Hirsch, L. Kaya, L. Lewandowski, D. Rosiak, D. Schneiders, M. Seidlitz, A. Vogt, K. Wolf, and K.O. Zell — Institut für Kernphysik, Universität zu Köln

Reduced transition strengths expressed by B(E2) values are sensitive signatures to describe collective excitations of atomic nuclei and the evolution of shell structures. Along the N=Z line in the 0f1p shell they provide stringent tests of present shell-model interactions. Recently determined B(E2, 2₁⁺→ 0_g.s.⁺) values for self-conjugate nuclei in the 0f_7/2 shell showed an enhanced collective behavior [1]. The soft shell closure at N=Z=28 is of particular interest as it has been shown that the doubly-closed shell structure is substantially broken [2]. In order to investigate the interplay between single-particle and collective characters of low-lying states, lifetime measurements employing the Doppler-shift attenuation method (DSAM) were performed at the FN tandem accelerator at the IKP, Cologne. Excited states in ₂₂⁴⁴Ti, ₂₄⁴⁸Cr, ₂₆⁵²Fe, and ₂₈⁵⁶Ni were populated with fusion-evaporation reactions. The emitted γ rays were detected by an array of 11 HPGe detectors. First results on lifetimes and corresponding B(E2) values will be presented and discussed.

[1] K. Arnswald et al. Phys. Lett. B 772, 599 (2017)

[2] Otsuka et al. Phys. Rev. Lett. 81, 1588 (1998)