Verification of the Applicability of Water Cherenkov Detector to Active Neutron Method and Development of a Prototype Detector

Abstract

In the fields of nuclear security, a compact and low-cost non-destructive assay system to detect hidden nuclear material is required. Because the conventional active neutron method adopts an accelerator neutron source and <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> He detectors, existing instruments are expensive and poorly portable. To solve this problem, we have developed an innovative nuclear material detection method using a <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">252</sup> Cf source, which is called the rotation method. In this study, we developed a water Cherenkov detector as a novel low-cost neutron detector to replace <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> He detectors. The applicability of the water Cherenkov detector to the rotation method was validated using simulation. Subsequently, a prototype detector was subjected to a demonstration experiment, combined with the rotation device. As a result, the fission neutrons from nuclear material were measured by using pulse height discrimination. Our study shows a potential of the water Cherenkov detector as a neutron detector for the rotation method.