Simultaneous measurement of (n,γ) and (n,fission) cross sections with the DANCE 4π BaF2 array

Abstract

Neutron capture cross section measurements on many of the actinides are complicated by low‐energy neutron‐induced fission, which competes with neutron capture to varying degrees depending on the nuclide of interest. Measurements of neutron capture on 235U using the Detector for Advanced Neutron Capture Experiments (DANCE) have shown that we can partially resolve capture from fission events based on total photon calorimetry (i.e. total γ‐ray energy and γ‐ray multiplicity per event). The addition of a fission‐tagging detector to the DANCE array will greatly improve our ability to separate these two competing processes so that improved neutron capture and (n,γ)/(n,fission) cross section ratio measurements can be obtained. The addition of a fission‐tagging detector to the DANCE array will also provide a means to study several important issues associated with neutron‐induced fission, including (n,fission) cross sections as a function of incident neutron energy, and total energy and multiplicity of prompt fission photons. We have focused on two detector designs with complementary capabilities, a parallel‐plate avalanche counter and an array of solar cells.