S-Wave Neutron Strength Functions of the Gd Isotopes

The neutron resonance structure of the gadolinium isotopes ${\mathrm{Gd}}^{155}$, ${\mathrm{Gd}}^{156}$, ${\mathrm{Gd}}^{157}$, ${\mathrm{Gd}}^{158}$, and ${\mathrm{Gd}}^{160}$ has been investigated over a wide energy region to determine the $s$-wave neutron strength functions, resonance parameters, and potential scattering radii. Values of the neutron strength functions as derived from an analysis of the average cross section in the keV region are found to be 2.4±0.2, 1.9±0.4, and 2.2±0.2, all in units of ${10}^{-4\mathrm{}}$, for ${\mathrm{Gd}}^{155}$, ${\mathrm{Gd}}^{156}$, and ${\mathrm{Gd}}^{157}$, respectively. For ${\mathrm{Gd}}^{158}$ and ${\mathrm{Gd}}^{160}$, the values, as obtained from the resonance parameters, are 1.6±0.6 and 2.5±1.3. In addition, the 2200-m/sec cross sections and absorption resonance integrals are computed and are compared with available experimental data.