The feeding times and lifetimes of high-spin levels in ytterbium doubly even isotopes

Rotational states of doubly even sup(160,162,164,166)Yb isotopes with spins up to (10-20)h are investigated. Feeding of the Yb isotopes states was achieved through the (40Ar, 4n) reactions on the sup(124,124,128,130)Te targets. The recoil-distance Doppler-shift method was used. Both absolute and relative intensities of shifted and unshifted peaks of Yb nucleus energy-level transitions were measured. The energy levels, relative intensities of lateral feeding, mean time of the lateral feeding and lifetimes of the Yb isotopes Yrast bands are tabulated. The obtained values of rotational level lifetimes are compared with the predictions of the rigidrotor model. For the sup(164,166)Yb isotopes a small retardation (by a factor of 1.2-1.4) of transitions is found in the backbending region. Some properties (moment of inertia, quadrupole deformation parameter, etc.) of the Yb isotope rotational bands are discussed. The results obtained are compared with results for similar nuclei obtained elsewhere