Development of an odd-Z-projectile reaction for heavy element synthesis: 208Pb(64Ni, n)271Ds and 208Pb(65Cu, n)272111

Seven {sup 271}Ds decay chains were identified in the bombardment of {sup 208}Pb targets with 311.5- and 314.3-MeV {sup 64}Ni projectiles using the Berkeley Gas-filled Separator. These data, combined with previous results, provide an excitation function for this reaction. From these results, an optimum energy of 321 MeV was estimated for the production of {sup 272}111 in the reaction {sup 208}Pb({sup 65}Cu, n). One decay chain was observed, resulting in a cross section of 1.7{sub -1.4}{sup +3.9} pb. This experiment confirms the discovery of element 111 by the Darmstadt group who used the {sup 209}Bi({sup 64}Ni, n){sup 272}111 reaction