Neutron resonance fission neutron analysis for nondestructive fissile material assay

Hironaka, Kota ; Lee, J. ; Koizumi, Mitsuo ; Ito, Fumiaki*; Hori, Junichi*; Terada, Kazushi*; Sano, Tadafumi*

We propose neutron resonance fission neutron analysis (NRFNA), an active nondestructive assay (NDA) technique, to improve the capability to identify and quantify a small amount of fissile material in a sample. NRFNA uses pulsed neutrons to induce fission reactions in the sample. Fission neutrons are detected by a neutron-gamma pulse shape discrimination (PSD) scintillation detector with time-of-flight (TOF) technique. The obtained nuclide-specific resonance peaks in the neutron energy spectrum provide information to identify and quantify a fissile material in the sample. The possibility of using PSD for NRFNA was confirmed through a test experiment using a natural uranium sample. We successfully observed the resonance peaks from U(n,f) reaction and showed that NRFNA would be useful for measuring a small amount of fissile material in a sample.