Dresden 2000 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 16: Postersitzung / Kernphysik
HK 16.11: Poster
Donnerstag, 23. März 2000, 10:15–12:45, B 69
g Factor Measurements of the first 2+ and 3− States in 90Zr + — •K.-H. Speidel1, R. Ernst1, N. Benczer-Koller2, G. Jakob2, G. Kumbartzki2, J. Holden2 und T. Mertzimekis2 — 1Inst. für Strahlen- und Kernphysik, Univ. Bonn, D-53115 Bonn — 2Dept. of Physics & Astronomy, Rutgers Univ., NJ, USA
For the doubly magic 90Zr nucleus we have determined for the first time the g factors of the first 2+ and 3− states at 2.186 MeV and 2.747 MeV, respectively. This experiment is part of a systematic study of all stable even-even Zr isotopes. For 92.94Zr(2+, 4+) states large negative g factors have been measured recently clearly showing the dominance of d5/2 neutron configurations in the wave functions of these nuclei near N=50 shell closure [1]. In the present measurements 90Zr beams of 270MeV and 300MeV from the tandem accelerator of Yale university were Coulomb excited on a thin 24Mg target.Inverse kinematics was combined with the technique of transient magnetic fields using Gd as ferromagnetic host. Coincident γ rays were detected with large NaI(Tl) scintillators. A Ge detector at 0∘ to the beam was used to redetermine the lifetime of the 2+ state with the DSAM technique. Whereas at the lower beam energy essentially the 2+ state was excited, at higher beam energy the decay of the 3− state to the 2+ state dominated the spectra due to strong nuclear force excitation. Preliminary results of g factors and the B(E2,2+→0+) will be discussed.
[1] G. Jakob et al., Phys. Lett. B in press + supported by DFG and BMBF