Comparison of reactions for the production of {sup 258,257}Db: {sup 208}Pb({sup 51}V,xn) and {sup 209}Bi({sup 50}Ti,xn)

Excitation functions for the 1n and 2n exit channels of the {sup 208}Pb({sup 51}V,xn){sup 259-x}Db reaction were measured. A maximum cross section of the 1n exit channel of 2070{sub -760}{sup +1100} pb was measured at an excitation energy of 16.0 {+-} 1.8 MeV. For the 2n exit channel, a maximum cross section of 1660{sub -370}{sup +450} pb was measured at 22.0 {+-} 1.8 MeV excitation energy. The 1n excitation function for the {sup 209}Bi({sup 50}Ti,n){sup 258}Db reaction was remeasured, resulting in a cross section of 5480{sub -1370}{sup +1730} pb at an excitation energy of 16.0 {+-} 1.6 MeV, in agreement with previous values [F. P. Hessberger et al., Eur. Phys. J. A 12, 57 (2001)]. Differences in cross section maxima are discussed in terms of the fusion probability below the barrier.