Berlin 2005 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 17: Kernphysik/Spektroskopie

HK 17.1: Gruppenbericht

Montag, 7. März 2005, 14:00–14:30, TU MA004

Search for New Shell Structure in Neutron-Rich Cr Isotopes^* — •A. Bürger¹, T. Saito², A. Al-Khatib¹, A. Banu², T. Beck², F. Becker², P. Bednarczyk², G. Benzoni³, P. Doornenbal⁴, J. Gerl², H. Geissel², M. Górska², H. Grawe², J. Grȩbosz², G. Hammond⁵, H. Hübel¹, M. Kavatsyuk², O. Kavatsyuk², I. Kojuharov², M. Kmiecik⁶, N. Kurz², R. Lozeva², A. Maj⁶, S. Mandal², Zs. Podolyák⁷, P. Reiter⁴, N. Saito², H. Weick², O. Wieland³, and H.-J. Wollersheim² — ¹HISKP, Univ. Bonn — ²GSI, Darmstadt — ³Univ. Milano, Italy — ⁴IKP, Univ. Köln — ⁵Keele Univ., UK — ⁶IFJ PAN, Kraków, Poland — ⁷Univ. of Surrey, UK

Very neutron rich nuclei may exhibit new shell structure due to the monopole part of the effective nuclear interaction and a modification of the spin-orbit force. For the Cr isotopes, the excitation energies of the first 2⁺ states suggest a possible subshell closure at N=32 [1], however B(E2) values as a crucial signature are missing for instable isotopes. We have determined the B(E2;2⁺→ 0⁺) for ^54,56,58Cr from relativistic Coulomb excitation using the FRS-RISING setup at GSI. The Cr ions produced by fragmentation of a high-energy ⁸⁶Kr beam impinged on a secondary Au target at an energy of ≈ 100· A MeV. Gamma-rays were observed by the Ge Cluster detectors of the RISING setup and recorded together with particle and position information. The B(E2) values for ^54,56,58Cr will be compared to results of new shell model calculations.

[1] D. Appelbe et al., Phys. Rev. C 67, 034309 (2003)

^*Supported by BMBF, DFG and the Polish Committee for Scientific Research.