GANIL

[paper] First g(2+) measurement on neutron-rich 72Zn, and the high-velocity transient field technique for radioactive heavy-ion beams

First g(2+) measurement on neutron-rich 72Zn, and the high-velocity transient field technique for radioactive heavy-ion beams

E. Fiori et al.

doi: 10.1103/PhysRevC.85.034334

The high-velocity transient-field (HVTF) technique was used to measure the g factor of the 2+ state of 72Zn produced as a radioactive beam. The transient-field strength was probed at high velocity in ferromagnetic iron and gadolinium hosts using 76Ge beams. The potential of the HVTF method is demonstrated and the difficulties that need to be overcome for a reliable use of the TF technique with high-Z, high-velocity radioactive beams are revealed. The polarization of K-shell vacancies at high velocity, which shows more than an order of magnitude difference between Z=20 and Z=30 is discussed. The g-factor measurement hints at the theoretically predicted transition in the structure of the Zn isotopes near N=40

[paper] g factor of the 44Cl ground state: Probing the reduced Z=16 and N=28 gaps

g factor of the 44Cl ground state: Probing the reduced Z=16 and N=28 gaps

M. De Rydt et al.

doi: 10.1103/PhysRevC.81.034308

The g factor of the 44Cl ground state is measured at the LISE fragment separator at the Grand Acclérateur National d’Ions Lourds (GANIL) using the β nuclear magnetic resonance technique, resulting in g(44Cl)=(-)0.2749(2). An analysis of the g factor value and of the theoretical level scheme in the shell-model framework reveals the presence of odd-proton s1/2 configurations and neutron excitation across the N=28 shell gap in the ground state of 44Cl. In addition, the measured g factor strongly supports a 2 spin assignment for the 44Cl ground state.

[paper] g factor of the exotic N=21 isotope 34Al: probing the N=20 and N=28 shell gaps at the border of the "island of inversion"

g factor of the exotic N=21 isotope 34Al: probing the N=20 and N=28 shell gaps at the border of the "island of inversion"

P. Himpe et al.

doi: 10.1016/j.physletb.2007.11.017

For the first time the g factor of an isotope beyond N=20 near the "island of inversion" has been measured. A 34Al radioactive beam was produced in a one-neutron pickup reaction on a 36S primary beam at 77.5 MeV/u, providing a large spin-polarization for application of the β-Nuclear Magnetic Resonance (β-NMR) method. The measured g factor of 34Al, |g|=0.539(2), combined with results from earlier β-decay studies, allows to firmly assign a ground state spin/parity 4. Comparison to large scale shell model calculations reveals that a dominant amount of intruder components is needed in the 34Al wave function to account for the observed large magnetic moment μ=(+)2.156(16)μN. This reveals Z=13 to be a true "transition number" between the normal Z=14 Si isotopes and the abnormal Z=12 Mg isotopes. The sensitivity of this odd–odd ground state dipole moment to the N=20, as well as the N=28 gap, reveals that both are significantly reduced, despite Z=13 being outside the conventional island of inversion.