Development of delayed gamma-ray spectroscopy for nuclear material evaluation; Neutron detection system

Lee, H.-J.; Koizumi, Mitsuo ; Rodriguez, D. C. ; Rossi, F.  ; Takahashi, Tone

Under the MEXT subsidy for promoting nuclear security related activities, the Japan Atomic Energy Agency (JAEA) is developing Delayed Gamma-ray Spectroscopy (DGS) for nuclear safeguards verification. Our goal is to design a compact DGS instrument by combining a neutron irradiation system and a gamma-ray measurement system. This DGS instrument requires a neutron detection system in order to monitor neutrons for both source consistency and mass correlation evaluations. The JAEA is investigating He-3 and He-4 neutron detectors for these evaluations. We introduce how our neutron detection system works within the compact DGS instrument and then present current calibration efforts, and various studies performed with these neutron detection devices.