Activation cross section of the (n,2n) reaction on Hf isotopes

Cross sections of the 174 Hf(n,2n) 173 Hf and 176 Hf(n,2n) 175 Hf reactions have been experimentally determined relative to the 27 Al(n, α) 24 Na reference reaction at incident neutron energies of 15.3 and 17.1 MeV by means of the activation technique. The irradiations were carried out at the 5 MV tandem T11/25 Accelerator Laboratory of NCSR "Demokritos" with monoenergetic neutron beams provided via the 3 H(d,n) 4 He reaction, using a new Ti-tritiated target of 373 GBq activity. In the determination of the 176 Hf(n,2n) 175 Hf reaction cross section the contamination of the 174 Hf(n, γ ) 175 Hf and 177 Hf(n,3n) 175 Hf reactions has been taken into account. Moreover, the neutron beam energy has been studied by means of Monte Carlo simulation codes and the neutron flux has been determined via the 27 Al(n,α) 24 Na reference reaction.