Influence of projectile neutron number in the {sup 208}Pb({sup 48}Ti, n){sup 255}Rf and {sup 208}Pb({sup 50}Ti, n){sup 257}Rf reactions

Four isotopes of rutherfordium, {sup 254-257}Rf, were produced by the {sup 208}Pb({sup 48}Ti, xn){sup 256-x}Rf and {sup 208}Pb({sup 50}Ti, xn){sup 258-x}Rf reactions (x=1,2) at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. Excitation functions were measured for the 1n and 2n exit channels. A maximum likelihood technique, which correctly accounts for the changing cross section at all energies subtended by the targets, was used to fit the 1n data to allow a more direct comparison between excitation functions obtained under different experimental conditions. The maximum 1n cross sections of the {sup 208}Pb({sup 48}Ti, n){sup 255}Rf and {sup 208}Pb({sup 50}Ti, n){sup 257}Rf reactions obtained from fits to the experimental data are 0.38{+-}0.07 nb and 40{+-}5 nb, respectively. Excitation functions for the 2n exit channel were also measured, with maximum cross sections of 0.40{sub -0.17}{sup +0.27} nb for the {sup 48}Ti induced reaction, and 15.7{+-}0.2 nb for the {sup 50}Ti induced reaction. The impact of the two neutron difference in the projectile on the 1n cross section is discussed. The results are compared to the Fusion by Diffusion model developed by Swiatecki, Wilczynska, and Wilczynski.