Lawrence Berkeley National Laboratory

The production of neutron-deficient transactinide isotopes using cold fusion reactions has been studied in recent experiments with the Berkeley Gas-filled Separator (BGS). These experiments were part of a systematic study of using odd-Z projectile reactions for heavy element synthesis. Targets of 208Pb were bombarded with projectiles of 64Ni, 65Cu, and 55Mn to produce 271Ds, 272-111, and isomers of 262Bh, respectively. The excitation function of the 208Pb(64Ni,n)271Ds reaction was measured and seven atoms of 271Ds were produced. This result was used to estimate the optimum beam energy for the 208Pb(65Cu,n) reaction, and one decay chain of 272-111 was observed. Lastly, the excitation function of the 208Pb(55Mn,n)262Bh reaction was measured and preliminary results will be presented. These results will be characterized in terms of the performance and use of the BGS for heavy element production.