Excitation Function For The Production Of (262)Bh (Z=107) In The Odd-Z-Projectile Reaction Pb-208(Mn-55, N)

The excitation function for production of (262)Bh in the odd-Z-projectile reaction Pb-208(Mn-55, n) has been measured at three projectile energies using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. In total, 33 decay chains originating from (262)Bh and 2 decay chains originating from (261)Bh were observed. The measured decay properties are in good agreement with previous reports. The maximum cross section of 540(-150)(+180) pb is observed at a lab-frame center-of-target energy of 264.0 MeV and is more than five times larger than that expected based on previously reported results for production of (262)Bh in the analogous even-Z-projectile reaction Bi-209(Cr-54, n). Our results indicate that the optimum beam energy in one-neutron-out heavy-ion fusion reactions can be estimated simply using the optimum energy rule proposed by Swiatecki, Siwek-Wilczynska, and Wilczynski.