Nondestructive and active interrogation system for special nuclear material: proof of principle and initial results

Herein, we employ the threshold energy neutron analysis (TENA) technique to introduce the world's first active interrogation system to detect special nuclear materials (SNMs), including U-235 and Pu-239. The system utilizes a DD neutron generator based on inertial electrostatic confinement (IEC) to interrogate suspicious objects. To detect secondary neutrons produced during fission reactions induced in SNMs, a tensioned metastable fluid detector (TMFD) is employed. The current status of the system's development is reported in this paper, accompanied by the results from experiments conducted to detect 10 g of highly enriched uranium (HEU). Notably, the experimental findings demonstrate a distinct difference in the count rates of measurements with and without HEU. This difference in count rates surpasses two times the standard deviation, indicating a confidence level of more than 96% for identifying the presence of HEU. The paper presents and extensively discusses the proof-of-principle experimental results, along with the system's planned trajectory.