Review of Livermore-Led Neutron Capture Studies Using DANCE Review of Livermore-Led Neutron Capture Studies Using DANCE

Abstract. We have made neutron capture cross-section measurements using the white neutron source at the Los Alamos Science Center, the DANCE detector array (Detector for Advanced Neutron Capture Experiments) and targets important for basic science and stockpile stewardship. In this paper, we review results from (n,γ) reactions on 94,95 Mo, 152,154,157,160,nat Gd, 151,153 Eu and 242m Am for neutron energies from < 1eV up to ~ 20 keV. We measured details of the γ-ray cascade following neutron capture, for comparison with results of statistical model simulations. We determined the neutron energy dependent (n,γ) cross section and gained information about statistical decay properties, including the nuclear level density and the photon strength function. Because of the high granularity of the detector array, it is possible to look at gamma cascades with a specified number of transitions (a specific multiplicity). We simulated γ-ray cascades using a combination of the DICEBOX/GEANT computer codes. In the case of the deformed nuclei, we found evidence of a scissors-mode resonance. For the Eu, we also determined the (n,γ) cross sections. For the 94,95 Mo, we focused on the spin and parity assignments of the resonances and the determination of the photon strength functions for the compound nuclei 95,96 Mo. Future plans include measurements on actinide targets; our immediate interest is in 242m Am