SUPERDEFORMED BANDS IN TL-189

Two superdeformed bands of IO transitions each have been found in Tl-1 89 extending the mass 190 region of superdeformation down to neutron n umber N=108. The new bands can be interpreted as signature partners an d are proposed to be based on a proton i(13/2) ( Omega=5/2) configurat ion, in analogy with the yrast superdeformed band structures in the he avier odd-mass Tl isotopes. The dynamic moments of inertia of all thes e bands show no noticeable differences as function of N, consistent wi th an essentially constant quadrupole deformation from the center of t he island to its edges. [S0556-2813(98)50911-9].