Lifetime Measurements of Superdeformed Bands in148–149Gdand152Dy:Evidence for Structure-Dependent Elongations

Precise level lifetimes have been measured for various superdeformed bands in ${}^{148,149}\mathrm{Gd}$ and ${}^{152}\mathrm{Dy}$ with the Doppler-shift attenuation method. From the derived quadrupole moments, $Q_0$, we find large differences in deformation between the yrast bands and some excited bands in the gadolinium isotopes. Moreover, two of the excited Gd bands and the ${}^{152}\mathrm{Dy}$ yrast band, which have identical moments of inertia, have different elongations, supporting the picture that alignment and deformation effects cancel in identical bands.