G-factor measurements at RISING: The cases of 127Sn and 128Sn

Abstract

We report on g-factor measurements of the 19/2+ T1/2 =4.5(3) μs isomer in 127Sn and the 10+ T1/2 =2.69(23) μs isomer in 128Sn. These isomers were produced and spin-aligned in relativistic heavy-ion fragmentation at GSI and were selected and separated by the GSI fragment separator (FRS). The γ-rays of the isomeric decay were detected by the RISING γ-ray spectrometer. The method of time-differential perturbed angular distributions was utilized. The measured g-factors, g(19/2+; 127Sn) =-0.17(2) and g(10+; 128Sn)=-0.20(4), are compared with shell model calculations. The measured g-factors confirm the predominantly ?h 11/2-2 and ?(8 1/2-1h 11/2-2) character of the 10+ and 19/2 - isomers in 128Sn and 127Sn, respectively. The results demonstrate the feasibility of the method for similar measurements in exotic neutron-rich nuclei. © 2010 EPLA.