Darmstadt 2008 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 15: Kernphysik / Spektroskopie
HK 15.4: Talk
Monday, March 10, 2008, 17:30–17:45, 2G
Investigation of neutron-deficient 21Mg by collinear laser spectroscopy and β-NMR — Klaus Blaum1, Kieran T. Flanagan3, Christopher Geppert1, Magdalena Kowalska2, •Jörg Krämer1, Peter Lievens3, Gerda Neyens3, Rainer Neugart1, Wilfried Nörtershäuser1, Marieke de Rydt3, Pieter Vingerhoets3, and Deyan T. Yordanov3 — 1Univ. Mainz, Germany — 2CERN, Switzerland — 3K.U.Leuven, Belgium
We present recent results of collinear laser spectroscopy measurements on 21Mg performed at ISOLDE (CERN). The radioactive Mg ions were produced by 1.4 GeV protons impinging on a SiC target and subsequent selective resonant ionization of the reaction products by a laser ion source. The extracted and mass-separated beam is superimposed with an ultra violet cw laser beam in collinear geometry and optical pumping is performed in a weak magnetic guiding field. If the laser is at resonance with the ionic transition, nuclear spin polarization is created by optical pumping of the hyperfine structure Zeeman levels. After implantation into a suitable crystal an asymmetry in the spatial distribution of the positrons from the β+ decay can be observed. Detecting this β-asymmetry while Doppler-tuning the laser wavelength yields the hyperfine structure. High-resolution β-NMR measurements were also performed and the nuclear g-factor was determined. After combining the results of β-asymmetry and β-NMR, also the nuclear spin of 21Mg could be extracted. The results will be compared to nuclear shell-model predictions, and an outlook to further experiments will be given.