COULOMB-EXCITATION STUDIES TO HIGH-SPIN IN CM-248

Coulomb excitation studies of Cm-248 were carried out with 5.3 MeV u-1 Pb-208 projectiles from the GSI UNILAC. A rotational band built on th e ground state of Cm-248 has been identified to spin 28+ and a tentati ve 30+ assignment has been made. The angular dependence of the yields for transitions de-exciting levels from spin 28+ to 6+ have been measu red and used to support the spin and parity assignments. An anomalous level spacing is observed above 22+ and is interpreted as the crossing of a rotation-aligned band at high spin. The E2 matrix elements conne cting the states of the ground-state band up to 28+ have been determin ed by comparing the experimental yields to calculations based on semi- classical Coulomb excitation with subsequent gamma-ray decay. The effe ct of the excitation of other collective states is also considered. No strong deviation of the matrix elements from rigid-rotor behaviour ha s been seen.