Reaction mechanisms of fast neutrons on ${}^{51}\mathrm{V}$ below 21 MeV

Cross sections of the ${}^{51}\mathrm{V}{\mathrm{}(n,p)\mathrm{}}^{51}\mathrm{Ti},$ ${}^{51}\mathrm{V}(n,\alpha {)}^{48}\mathrm{Sc},$ and ${}^{\mathrm{nat}}\mathrm{V}(n,x\alpha {)}^{47}\mathrm{Sc}$ reactions were measured in the energy range from 11.7 to 20.5 MeV. The measurements for the latter reaction establish for the first time a consistent excitation curve. The present data for the $\mathrm{}(n,p)\mathrm{}$ process connect the measurements around 14 MeV with the recent data set above 17 MeV. The shapes and magnitudes of the three excitation functions from the reaction thresholds up to 21 MeV, as well as the ones for the competing reaction channel ${}^{51}\mathrm{V}{\mathrm{}(n,2n)\mathrm{}}^{50}\mathrm{V},$ are described by model calculations using a consistent parameter set. The agreement between experimental and calculated data is, in general, good both at the maxima and at the tails of the excitation functions. In contrast to earlier studies, the major contribution to the ${}^{\mathrm{nat}}\mathrm{V}(n,x\alpha {)}^{47}\mathrm{Sc}$ cross section at 14.8 MeV incident energy is attributed to the ${}^{50}\mathrm{V}(n,\alpha {)}^{47}\mathrm{Sc}$ reaction; at energies above 15 MeV the ${}^{51}\mathrm{V}{(n,n}^{\prime }\alpha )$ process is dominant.