Nuclear level densities of64,66Zn from neutron evaporation

Double differential cross sections of neutrons from $d\phantom{\rule{0.16em}{0ex}}+{\phantom{\rule{0.16em}{0ex}}}^{63,65}$Cu reactions have been measured at deuteron energies of 6 and 7.5 MeV. The cross sections measured at backward angles have been compared to theoretical calculations in the framework of the statistical Hauser-Feshbach model. Three different level density models were tested: the Fermi-gas model, the Gilbert-Cameron model, and the microscopic approach through the Hartree-Fock-Bogoliubov method (HFBM). The calculations using the Gilbert-Cameron model are in best agreement with our experimental data. Level densities of the residual nuclei ${}^{64}$Zn and ${}^{66}$Zn have been obtained from statistical neutron evaporation spectra. The angle-integrated cross sections have been analyzed with the exciton model of nuclear reaction.