Transient fieldgfactor and mean-life measurements with a rare isotope beam of126Sn

Background: The g factors and lifetimes of the 21+ states in the stable, proton-rich Sn isotopes have been measured, but there is scant information on neutron-rich Sn isotopes. Purpose: Measurement of the g factor and the lifetime of the 21+ state at 1.141 MeV in neutron-rich 126Sn (T 1/2=2. 3×105y). Method: Coulomb excitation in inverse kinematics together with the transient field and the Doppler shift attenuation techniques were applied to a radioactive beam of 126Sn at the Holifield Radioactive Ion Beam Facility. Results: g(21+)=-0.25(21) and τ(21+)=1.5(2) ps were obtained. Conclusions: The data are compared to large-scale shell-model and quasiparticle random-phase calculations. Neutrons in the h 11/2 and d 3/2 orbitals play an important role in the structure of the 21+ state of 126Sn. Challenges, limitations, and implications for such experiments at future rare isotope beam facilities are discussed. © 2012 American Physical Society