Lifetime measurements of superdeformed bands in Gd-148-149 and Dy-152: Evidence for structure-dependent elongations

Precise level lifetimes have been measured for various superdeformed bands in Gd-148,Gd-149 and Dy-152 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 Dy-152 yrast band, which have identical moments of inertia, have different elongations, supporting the picture that alignment and deformation effects cancel in identical bands.