International Conference on Nuclear Data for Science and Technology 2007
DOI: 10.1051/ndata:07245

Review of Livermore-led neutron capture studies using DANCE

W.E. Parker¹, S.A. Sheets², U. Agvaanluvsan¹, J.A. Becker¹, F. Becvar³, T.A. Bredeweg⁴, R. Clement⁴, A. Couture⁴, E. Esch⁴, R.C. Haight⁴, M. Jandel⁴, M. Krticka³, G.E. Mitchell⁵, R. Macri¹, J.M. O'Donnell⁴, R. Reifarth⁴, R.S. Rundberg⁴, J.M. Schwantes⁴, J.L. Ullmann⁴, D.J. Vieira⁴, J.M. Wouters⁴ and P.A. Wilk<sup>1

1</sup>  Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
²  North Carolina State University, Raleigh, NC 27695, USA presently at Lawrence Livermore National Laboratory
³  Charles University in Prague, 1800 00 Prague 9, Czech Republic
⁴  Los Alamos National Laboratory, Los Alamos, NM 87545, USA
⁵  North Carolina State University, Raleigh, NC 27695, USA and Triangle Universities Nuclear Laboratory, Durham, NC 27708, USA

Published online: 21 May 2008

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 ^94,95Mo, ^{152,154,157,160,nat}Gd, ^151,153Eu and ^242mAm for neutron energies from < 1 eV 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 ^94,95Mo, we focused on the spin and parity assignments of the resonances and the determination of the photon strength functions for the compound nuclei ^95,96Mo. Future plans include measurements on actinide targets; our immediate interest is in ^242mAm.

© CEA 2008