Neutron Resonance Spectroscopy. VII. Ti, Fe, and Ni

Abstract

High-resolution neutron total cross-section measurements were performed on natural samples of titanium, iron, and nickel from 200 eV to a few MeV using the Nevis synchrocyclotron neutron velocity spectrometer with a 200-m flight path. The energy resolution was adequate only up to 200 keV to perform a detailed $R$-matrix multilevel analysis of the data. The resonance energies, isotopic and $l$-value assignment, neutron widths, etc., up to this energy have been determined. From these the mean level spacings $〈D〉$ and the $s$-wave strength functions ($S_0$) have been calculated. Information about the resonance parameters of the bound level in iron and nickel has been also obtained. Values of ${\Gamma }_{\gamma }=8.2\mathrm{}$ eV for the ${\mathrm{Ti}}^{48}$ (17.8 keV) resonance, ${\Gamma }_{\gamma }=0.64\mathrm{}$ for the bound level at -2 keV in ${\mathrm{Fe}}^{56}$, and ${\Gamma }_{\gamma }=9.0\mathrm{}$ eV for the bound level at -28.5 keV in ${\mathrm{Ni}}^{58}$ have been determined by requiring an agreement with the measured thermal-neutron-capture cross section in these nuclei.