Gyromagnetic ratios of 4+ and 6+ states in156Gd and158Gd

Abstract

The followingg-factors have been derived from time integral measurements of γ-γ angular correlations in the static magnetic hyperfine field of magnetized gadolinium metal probes:156Gd:g(4 +1 )=+0.310(19)g(6 +1 )=+0.25(21)g(4 +3 , 1511 keV)=+0.809(27)158Gd:g(4 +1 )=+0.409(15).The 5.35d 156Tb sources were produced by the reaction156Gd(d, 2n)156Tb in our cyclotron. A carrier-free 150y 158Tb source was obtained from ISOLDE/CERN. In comparison with the precisely knowng-factors of the 2 +1 states,g(2 su+1 ,156Gd) =+0.386(4) andg(2 +1 ,158Gd)=0.381(4), we observe a large reduction for the156Gd 4 +1 state whereasg increases slightly for158Gd. The half-life of the 4 +1 state of158Gd was remeasured as158Gd:T 1/2(4 +1 )=148(2) ps. A measurement of the rotation in the 4 +3 state of156Gd in external magnetic fields of various strengths up toB ext=9.5 T did not confirm the anomalous dependence of the magnetic hyperfine field in gadolinium metal on the external field, which has been reported by Persson et al. [29].