g-factors of isomers around N approximate to 40, Z approximate to 28 from time-dependent Larmor precession on spin-aligned projectile-like fragments

First and preliminary results of an experiment aimed at measuring g-factors of isomeric states in neutron-rich nuclei in the vicinity of Ni-68 are reported, Isomers near the predicted N = 40 sub-shell closure in Cu-69, Ni-67 and Co-66 have been populated in the fragmentation of a Ge-76, 61.4 MeV/u beam onto a 145 mg/cm(2) (9)Bc target at GANIL. Here we report the results for the 357(2) ns, I-pi = 13/2(+) isomer in Cu-69 for which a preliminary gyromagnetic ratio of \g\ = 0.195(9) was derived. The Larmor precession of the spin-oriented isomeric ensemble was measured by recording gamma-ion correlations in a 20 mus time window. This pioneering experiment has indicated interesting nuclear structure information and shows promising possibilities for future studies of this kind. (C) 2002 Elsevier Science B.V. All rights reserved.