First results on the neutron-induced fission cross-section of 231Pa for incident neutron energies En > 17 MeV

First results on the neutron-induced fission cross-section of 231Pa for incident neutron energies En > 17 MeV are presented. The experiments were carried out with quasi mono-energetic neutrons produced in the reaction T(d, n)4He. Corrections for low-energy neutron background produced in this reaction at incident deuteron energies Ed > 2 MeV are taken into account and based on experimental data obtained by two different techniques. Despite the relatively large error bars at the higher neutron energies, the new cross-section values meet the accuracy requirements set by the IAEA and will allow to remove the hitherto existing large spread between different previously published data. Recent cross-section calculations describe well the new experimental results, which are in consistency with cross-section values obtained in a particle-transfer reaction at excitation energies corresponding to neutron energies En < 10 MeV.

► First neutron-induced fission cross section data measured for incident neutron energies larger than 17 MeV. ► Precision of cross-section data meet the accuracy requirements set by the IAEA. ► The new data allow removing the existing large spread between different previously published data. ► Cross section data are well described by recent calculations in the whole energy range from threshold to 21 MeV.