Relative deformations of superdeformed bands in Ce-131,Ce-132

The quadrupole moments Q(0) of five superdeformed bands in Ce-131,Ce-132 have been established using the Doppler-shift attenuation method; for the first time, we can compare relative deformations of yrast and excited bands in different nuclei to an accuracy of similar or equal to(5-7)%. Four of the five bands have very similar deformations, while the excited band in Ce-131 has a somewhat larger quadrupole moment. Important new information is presented on the shape-driving force of the vi(13/2) orbital, the stability of the second minimum with respect to particle excitations, the relative deformations of identical bands, the nature of the sidefeeding, and the time scale of the decay process.