The Japan Atomic Energy Agency (JAEA) is collaborating with the European Commission Joint Research Centre (EC/JRC) to develop delayed gamma-ray spectroscopy (DGS). Toward this, the JAEA Integrated Support Center for Nuclear Nonproliferation and Nuclear Security (ISCN) designed the Delayed Gamma-ray Test Spectrometer (DGTS) that uses a ²⁵²Cf source (DGTS-C). This instrument is used to refine the design for a compact, induced-fission safeguards technique to supplement current nuclear material accountancy in reprocessing facilities. Experiments were performed at PERLA laboratory of the EC/JRC Ispra, Italy site to evaluate the neutron-irradiation and associated instrumentation capabilities to obtain delayed gamma-ray spectral signatures of assayed nuclear material. Neutron count-rate measurements were performed using a ³He detector and confirmed with MCNP6 models that showed a fluence of ∼87.1×10${}^{-4}$ n cm⁻² n${}_{src}^{-1}$. Short time-pattern interrogations of various ²³⁵U and ²³⁹Pu samples resulted in quantifiable delayed gamma-ray peaks from fission products. The peak intensities and spectral signatures resulted in fissile nuclide distinction and linear mass-correlation results. Consequently, we confirm the practicality of this JAEA/ISCN instrument design for DGS interrogation safeguards capabilities.

日本原子能厅 (JAEA) 正在与欧盟委员会联合研究中心 (EC/JRC) 合作开发延迟伽马射线光谱 (DGS)。为此，JAEA 核不扩散和核安全综合支持中心 (ISCN) 设计了延迟伽马射线测试光谱仪 (DGTS)，它使用²⁵²Cf 源 (DGTS-C)。该仪器用于改进紧凑型诱导裂变保障技术的设计，以补充后处理设施中当前的核材料衡算。在 EC/JRC Ispra 意大利站点的 PERLA 实验室进行了实验，以评估中子辐照和相关仪器的能力，以获得化验核材料的延迟伽马射线光谱特征。中子计数率测量是使用³ He 探测器进行的，并用 MCNP6 模型进行了确认，该模型显示了 ∼87.1×10${}^{-4}$n cm ^-2 n${}_{秒rC}^{-1}$. 对各种²³⁵ U 和²³⁹ Pu 样品的短时间模式询问导致裂变产物产生可量化的延迟伽马射线峰。峰值强度和光谱特征导致裂变核素区分和线性质量相关结果。因此，我们确认了这种用于 DGS 审讯保障能力的 JAEA/ISCN 仪器设计的实用性。