G-factors of the ground- state rotational bands of 158,160,162Dy derived from perturbed γ-γ directional correlations following (α, 2n)-reactions

Abstract

The ground-state rotational bands of 158,160,162Dy were excited simultaneously by (α, 2n)-reactions with a natural gadolinium target. A gadolinium single crystal was used with the α-axis oriented in beam direction. It was cooled by liquid helium and magnetized by an external magnetic field of ± 4.5 T parallel to the beam axis. The rotations of γ-γ directional correlations in the static magnetic hyperfine field were measured by use of a ring of 12 large Ge-detectors. The g-factors of the 41+, 61+ and 81+ states were derived. The results exhibit a significant variation of g(I). A different behaviour of the g-factors of 162Dy and those of the two other even dysprosium isotopes is observed which is interpreted as the consequence of different strengths of the interaction matrix elements between the ground-state bands and the Stockholm (S)-bands.