SUPERDEFORMED STRUCTURES IN PB-197,PB-198

Two new superdeformed bands, which possess almost constant dynamic mom ents of inertia as a unction of rotational frequency, have been observ ed in Pb-197. They are thought to be based upon the favored and unfavo red signature components of an N=7 neutron intruder orbital. Previous work tentatively assigned a superdeformed band to Pb-198. The present work has confirmed this assignment. The properties of all the bands ar e discussed in terms of extended total Routhian surface calculations.