Fission Barrier of $^{254}$No at High Spin

Superheavy nuclei provide opportunities to study nuclear structure at the limits in charge, spin and excitation energy. These nuclei exist only because shell effects create a fission barrier $B_f$. Hence, it is important to determine $B_f$ and its spin dependence. For $^{254}$No, the maximum spin and energy were found [1] to be $I_{max} = 22\hbar$ and E* = 8 MeV in the reaction $^{208}$Pb($^{48}$Ca,2n) at a beam energy of 219 MeV. At 223 MeV, the maximum spin increases to $32\hbar$. In contrast, the spin in $^{220}$Th, produced [2] in the $^{176}$Yb($^{48} $Ca,4n) reaction at 206 and 219 MeV, saturates at $20\hbar$. A measurement of the entry distribution of $^{254}$No at 223 MeV has been performed to determine $B_f (I)$ and results will be reported.\\[4pt] [1] P. Reiter \textit{et al.}, Phys. Rev. Lett. 84, 3542 (2000).\\[0pt] [2] A. Heinz \textit{et al.}, Nucl. Phys. A682, 458c (2001)