Slow-Neutron Resonance Scattering in Ag, Au, and Ta

Abstract

Slow-neutron resonance scattering measurements by the "bright-line" technique have been used as a supplement to and a check on total cross section measurements. It has thus been possible to obtain a complete and consistent set of resonance parameters for the lowest energy resonances in Ag, Au, and Ta. It was determined that the one-level formula is very well obeyed over wide energy ranges for both the scattering and total cross section data. These resonance parameters are reported in the text with the values for the statistical weight factor, $g$, of $\frac{3}{4}$, $\frac{5}{8}$, and $\frac{9}{16}$ for ${\mathrm{Ag}}^{109}$, ${\mathrm{Au}}^{197}$, and ${\mathrm{Ta}}^{181}$, respectively.In addition it was determined that the nuclear radii are the same within experimental errors for the nonresonant and resonant spin states for Au and Ta. The results indicate that either the nuclear radii differ by 45% for the two spin states of ${\mathrm{Ag}}^{109}$ or the potential scattering of ${\mathrm{Ag}}^{107}$ is 55% larger than for ${\mathrm{Ag}}^{109}$.