Delayed gamma-ray analysis for characterization of fissile nuclear materials

Koizumi, Mitsuo ; Rossi, F. ; Rodriguez, D. ; Takamine, Jun ; Seya, Michio; Bogucarska, T.*; Crochemore, J.-M.*; Varasano, G.*; Abbas, K.*; Pedersen, B.*; Heyse, J.*; Paradela, C.*; Mondelaers, W.*; Schillebeeckx, P.*

Under the collaboration between the Japan Atomic Energy Agency (JAEA) and European Commissions' Joint Research Center (EC-JRC), development of four active neutron-interrogation non-destructive assay methods for nuclear non-proliferation and safeguards are in progress. The techniques are differential die-away analysis, delayed gamma-ray analysis (DGA), neutron resonance transmission analysis, and prompt gamma-ray analysis. Information obtained by each method is used complementarily to characterize a sample. DGA utilizes moderated pulsed neutrons from a D-T neutron generator to induce fission reaction of nuclear materials. Delayed gamma rays from the fission products (FP) are measured to determine the ratios of fissile nuclides (e.g. U, and Pu) in the sample. Experimental studies of the DGA method are in progress with the Pulsed Neutron Interrogation Test Assembly (PUNITA) in EC-JRC Ispra. Here we present an overview of the study plan of these DGA experiments along with the latest results. This research was implemented under the subsidiary for nuclear security promotion of MEXT.