Dresden 2000 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 16: Postersitzung / Kernphysik

HK 16.5: Poster

Donnerstag, 23. März 2000, 10:15–12:45, B 69

Precise Measurements of g Factors and B(E2)’s of the first 2⁺ States in ⁵⁸⁻⁶⁴Ni in Comparison with Large-Scale Shell Model Predictions ⁺ — •O. Kenn¹, K.-H. Speidel¹, R. Ernst¹, J. Gerber², P. Maier-Komor³, N. Benczer-Koller⁴, G. Kumbartzki⁴ und F. Nowacki⁵ — ¹Inst. für Strahlen- und Kernphysik, Univ. Bonn, D-53115 Bonn — ²Inst. de Recherches Subatomique, F-67037 Strasbourg, France — ³Physik-Dept. TU-München, D-85748 Garching — ⁴Dept. of Physics & Astronomy, Rutgers Univ., NJ,USA — ⁵Physique Theorique BAT.40/1 CRN, F-67037 Strasbourg, France

In view of the advent of radioactive beams and the possibility of making a ⁵⁶Ni beam for spectroscopic studies in particular, being of eminent interest due to its doubly magic shell closure, we have measured the g factors of the first 2⁺ states of even-even Ni isotopes. Former measurements [1] yielded rather poor accuracy which we could considerably improve by using the technique of projectile Coulomb excitation in inverse kinematics and transient fields. Isotopically pure Ni beams with energies of 155 MeV, provided by the tandem accelerator at Munich, were Coulomb excited with a natural carbon target. The γ rays were measured in coincidence with the forward recoiling carbon ions in large BaF₂ scintillators. A Ge detector at 0⁰ to the beam was used to measure the lifetime via the DSAM technique. Spin precessions in the transient field of ferromagnetic Gd yielded g factors of the first 2⁺ states of all five isotopes. The results are compared with large scale shell model calculations.

[1] M. Hass et al., Phys.Rev. C17 (1978) 997 ⁺supported by DFG and the BMBF