Neutron resonance parameters in155Gd measured with the DANCEγ-ray calorimeter array

Abstract

The ${}^{155}$Gd($n$,$\ensuremath{\gamma}$) reaction was measured with the DANCE $\ensuremath{\gamma}$-ray calorimeter at the Los Alamos Neutron Science Center. Spins were determined for the $s$-wave resonances by analysis of the $\ensuremath{\gamma}$-ray multiplicity distributions. The analysis was performed with a pattern recognition method. The resulting level densities for the $J=1$ and 2 resonances are in qualitative agreement with the expected 2$J$ $+$ 1 dependence. The average $s$-wave resonance spacing was determined to be ${D}_{0}=1.62$ $\ifmmode\pm\else\textpm\fi{}$ 0.15 eV. Analysis of the neutron resonances with the code sammy yielded the $s$-wave strength function ${S}_{0}=1.99\ifmmode\pm\else\textpm\fi{}0.28\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and the average total radiative width ${\ensuremath{\Gamma}}_{\ensuremath{\gamma}}$ $=$ 120 $\ifmmode\pm\else\textpm\fi{}$ 3 meV.