G-Factor of the First 2+ State in Then=82 Nucleus138ba

The 2 1 + level of138Ba has been Coulomb excited with a 105 MeV32S beam. The precession of the gamma ray angular distribution induced by the transient magnetic field when traversing a 2.14 mg/cm2 iron foil, has been measured to be 15.6(1.7) mr. A value of g(138Ba 2 1 + )=0.72(11) was obtained assuming for the transient field strength the Chalk River calibration. The field parametrization has been checked using the first 2+ state in150Sm as probe. Theg value obtained is sensibly lower than predicted by large scale shell model calculations in a proton subspace. Theg-factor of the first 2+ state in148Sm has been remeasured yieldingg(148Sm 2 1 + )=0.246(22).