Comparison of complementary reactions for the production of ^261,262Bh

Two heavy-ion induced fusion reactions producing ^261,262Bh were studied using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. An excitation function for the production of ²⁶²Bh via the reaction ²⁰⁹Bi(⁵⁴Cr,n)²⁶²Bh was measured with a maximum cross section from a fit to the data of 430 ± 110 pb observed at a compound nucleus excitation energy of 15.7 MeV. New data have been measured for the 1n exit channel of the ²⁰⁸Pb(⁵⁵Mn, n)²⁶²Bh reaction. We present an updated excitation function with an observed maximum cross section of 530±100 pb at a compound nucleus excitation energy of 14.1 MeV. Events corresponding to the 2n exit channel for the ²⁰⁹Bi(⁵⁴Cr,2n)²⁶¹Bh and ²⁰⁸Pb(⁵⁵Mn,2n)²⁶¹Bh reactions were also observed and are presented as partial excitation functions. The measured decay properties correspond well with existing experimental data. We compare these experimental results to cross section predictions from a model by Świa˛tecki et al. and discuss entrance channel effects on the magnitude of 1n cross sections.