München 2006 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 10: Kernphysik/Spektroskopie

HK 10.2: Vortrag

Montag, 20. März 2006, 17:00–17:15, C

Low-level structure of ⁷⁰Ge from lifetime measurements following α-transfer to ⁶⁶Zn ion beams⁺ — •J. Leske¹, K.-H. Speidel¹, S. Schielke¹, J. Gerber², P. Maier-Komor³, S.J.Q. Robinson⁴, Y.Y. Sharon⁵, and L. Zamick⁵ — ¹Helmholtz-Institut für Strahlen- und Kernphysik, Univ. of Bonn, Bonn, Germany — ²Institut de Recherches Subatomiques, Strasbourg, France — ³Physik.-Dept. TU München, Garching, Germany — ⁴Phys. Dept. Univ. of Southern Indiana, Evansville, IN, USA — ⁵Rutgers Univ., New Brunswick, NJ, USA

The g factor of the 2₁⁺ state in ⁷⁰Ge has been remeasured employing the α-transfer reaction to ⁶⁶Zn projectiles in combination with the technique of transient magnetic fields. Ion beams of 180 MeV were provided by the Munich tandem accelerator bombarding a multilayered target which consisted of carbon on thin Gd and Cu layers. The de-excitation γ rays were measured with NaI(Tl) scintillators and a Ge detector in coincidence with forward emitted α particles (from the decay of ⁸Be) being registered in a 0^∘ Si detector. Lifetimes of several excited states were measured using the Doppler-Shift-Attenuation method. In the analysis of the 2₁⁺ precession, requiring corrections for feeding from the 4₁⁺ state, a negative g factor of the 4₁⁺ state has to be assumed. This result would be consistent with a recent g factor measurement on the isotonic ⁶⁸Zn(4₁⁺) [1]: the negative g factor was attributed to a dominant g_9/2 neutron component in the nuclear wave function. The results are interpreted in the framework of large-scale fp shell model calculations.
⁺supported by the BMBF and DFG

[1] J. Leske et al., Phys. Rev. C72 (2005) 044301