Isomeric ratio measurements for the radiative neutron capture Lu176(n,γ) at the LANL DANCE facility

The isomeric ratios for the neutron capture reaction $^{176}$Lu($n,\gamma$) to the $J^{\pi}=5/2^-$ 761.7 keV, $T_{1/2}$ =32.8 ns and the $J^{\pi}=15/2^+$, 1356.9 keV, $T_{1/2}$=11.1 ns levels of $^{177}$Lu have been measured for the first time. The experiment was carried out with the Detector for Advanced Neutron Capture Experiments (DANCE) at the Los Alamos National Laboratory. Measured isomeric ratios are compared with talys calculations using different models for photon strength functions, level densities, and optical potentials. In order to reproduce the experimental γ-ray spectra, a low-energy resonance must be added in the photon strength function used in our Hauser-Feshbach calculations.