부산대학교 도서관

The $^{174}$Yb($^{29}$Si,5n) reaction at 148 MeV with thin targets was usedto populate high-angular momentum states in $^{198}$Po. Resulting $\gamma$ rayswere observed with Gammasphere. A weakly-populated superdeformed band of 10$\gamma$-ray transitions was found and has been assigned to $^{198}$Po. This isthe first observation of a SD band in the $A \approx 190$ region in a nucleuswith $Z > 83$. The ${\cal J}^{(2)}$ of the new band is very similar to those ofthe yrast SD bands in $^{194}$Hg and $^{196}$Pb. The intensity profile suggeststhat this band is populated through states close to where the SD band crossesthe yrast line and the angular momentum at which the fission process dominates.