G-FACTORS OF THE GROUND-STATE ROTATIONAL BANDS OF DY-158,DY-160,DY-162 DERIVED FROM PERTURBED GAMMA-GAMMA DIRECTIONAL CORRELATIONS FOLLOWING (ALPHA,2N)-REACTIONS

The ground-state rotational bands of Dy-158,Dy-160,Dy-162 were excited simultaneously by (alpha, 2n)-reactions with a natural gadolinium tar get. A gadolinium single crystal was used with the alpha-axis oriented in beam direction. It was cooled by liquid helium and magnetized by a n external magnetic field of +/-4.5T parallel to the beam axis. The ro tations of gamma-gamma directional correlations in the static magnetic hyperfine field were measured by use of a ring of 12 large Ge-detecto rs. The g-factors of the 4(1)(+), 6(1)(+) and 8(1)(+) states were deri ved. The results exhibit a significant variation of g(I). A different behaviour of the g-factors of Dy-162 and those of the two other even d ysprosium 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.