241Am Neutron Capture Cross Section in the keV region using Si and Fe-filtered neutron beams

Abstract

ABSTRACT The neutron capture cross-section of 241Am was measured in the keV neutron range using the recently implemented neutron filtering system of the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) beamline in the materials and life science (MLF) facility of the Japan Proton Accelerator Research Complex (J-PARC). Filter arrays consisting of 20 cm of nat Fe and nat Si were employed in separate measurements to provide filtered neutron beams with averaged neutron energies of 23.5 (Fe), 51.5 and 127.7 (Si) keV. The present 241Am results were obtained relative to the 197Au neutron capture yield by applying the total energy detection principle together with the pulse-height weighting technique. The 241Am neutron capture cross-section was determined as 2.72(29) b at 23.5 keV, 2.14(26) b at 51.5 keV and 1.32(10) b at 127.7 keV with total uncertainties in the range of 8 to 12%, much lower in comparison to the latest time-of-flight experimental data available.