Resonance parameters ofNi60+nfrom measurements of transmission and capture yields from 1 to 450 keV

High-resolution transmission and capture measurements of ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$-enriched targets have been made from a few eV to 1800 keV in transmission and from 2.5 keV to 5 MeV in capture. The transmission data from 1 to 452 keV were analyzed with a multilevel $R$-matrix code which uses Bayes' theorem for the fitting process. This code provides the energies and neutron widths of the resonances inside the 1- to 452-keV region as well as a possible parametrization for outside resonances to describe the smooth cross section in this region. The capture data were analyzed from 2.5 to 452 keV with a least-squares fitting code using the Breit-Wigner formula. Average parameters for the 30 observed $s$-wave resonances were deduced. The average level spacing, $D_0$, was found to be equal to 15.2±1.5 keV; the strength function, $S_0$, equal to (2.2±0.6)×${10}^{-4\mathrm{}}$; and the average radiation width, ${\overline{\Gamma }}_{\gamma }$, equal to 1.30±0.07 eV. The staircase plot of the reduced level widths and the plot of the Lorentz-weighted strength function averaged over various energy intervals show possible evidence for doorway states. The level densities calculated with the Fermi-gas model for $l=0\mathrm{}$ and for $l>\mathrm{}0\mathrm{}$ resonances were compared with the cumulative number of observed resonances, but the analysis is not conclusive. The correlation coefficient $\rho$ between ${\Gamma }_n^0$ and ${\Gamma }_{\gamma }$ is equal to 0.53±0.18. The average capture cross section as a function of the neutron incident energy is compared to the tail of the giant electric dipole resonance prediction.