Köln 2004 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 16: Nuclear Structure/Spectroscopy II
HK 16.4: Vortrag
Dienstag, 9. März 2004, 16:45–17:00, A
Optical polarization and β-asymmetry measurement on neutron-rich magnesium isotopes — •M. KOWALSKA1, K. BLAUM2, D. BORREMANS3, S. GHEYSEN3, P. HIMPE3, S. MALLION3, P. LIEVENS3, R. NEUGART1, G. NEYENS3, N. VERMEULEN3, and D. YORDANOV3 — 1University of Mainz, Germany — 2ISOLDE-CERN, Switzerland — 3K.U. Leuven, Belgium
The properties of neutron-rich Mg isotopes around N = 20 are very much influenced by intruder states from the f7/2 shell entering into the sp shell. This “island of inversion” is a challenge for nuclear shell-model calculations, and measurements of magnetic dipole and electric quadrupole moments are important as an experimental basis. For this purpose we have recently tested the conditions of β-NMR spectroscopy on short-lived Mg isotopes. 60 keV ion beams of 29Mg, 31Mg and 33Mg, produced by the RILIS ion source at ISOLDE-CERN, were polarized by collinear optical pumping with frequency-doubled laser light at 280 nm and were implanted into a cubic MgO crystal. Observation of the β-decay asymmetry as a function of the Doppler-tuned optical excitation frequency reveals the hyperfine structure of 29Mg and 31Mg in the 3s 2S1/2 → 3p 2P3/2 resonance transition. Preliminary information from these measurements about the involved spins and magnetic moments will be discussed. The observed asymmetries of up to 6% will allow us to perform accurate β-NMR measurements, from which g-factors and quadrupole moments can be deduced (supported by BMBF).