Plutonium Nuclear Resonance Fluorescence Measurements using Narrow Energy-Spread Photon Sources

Nuclear resonance uorescence (NRF) measurements have been made on plutonium targets at the High-intensity gamma source at Duke University. Therst measurements were performed on a 240Pu target with beam energies ranging from 2.1 to 3.1 MeV using high-purity germanium detectors. Some of these measurements used timing circuitry to reduce the relative intensity of the radioactive background emitted from the 240Pu target. These measurements suggest that some resonances that had previously been observed in weapons-grade Pu (WGPu) measurements may have been due to 240Pu, rather than 239Pu. More recent measurement have been focused on transmission measurement of WGPu for the purpose of non-destructive quantication of Pu content, as well as investigating additional NRF strength that may go unresolved in backscatter NRF measurements. Along with some results from these measurements, the potential to use narrow energy-spread photon sources to perform NRF-based assays of spent fuel and melted fuel debris will be discussed.