Experimental and theoretical study of the (n,2n) reaction on174,176Hf isotopes

Abstract

Cross sections for the ${}^{174}$Hf($n,2n$)${}^{173}$Hf and ${}^{176}$Hf($n,\phantom{\rule{-0.16em}{0ex}}2n$)${}^{175}$Hf reactions have been measured on the 5.5-MV Van de Graaff tandem accelerator of National Centre for Scientific Research ``Demokritos'' in Athens, in the neutron energy region from 8.8 to 11.0 MeV, using the activation technique. An experimental method to account for the contamination of the ${}^{176}$Hf($n,\phantom{\rule{-0.16em}{0ex}}2n$) reaction by the ${}^{174}$Hf($n,\phantom{\rule{-0.16em}{0ex}}\ensuremath{\gamma}$) reaction activated by the parasitic neutrons of the beam is presented. Statistical model calculations have also been performed using the nuclear-reaction codes empire-ii and talys. The results and effects of the nuclear input parameters as well as pre-equilibrium emission are discussed in detail.