Scintillator Coupled With Photographic Film For Application To Zero-knowledge Verification

Verifying the authenticity of nuclear warheads requires gaining confidence on whether or not an object is a nuclear weapon without revealing any sensitive information. A zero-knowledge protocol using pre-loadable superheated-emulsion (bubble) detectors has previously been proposed for this purpose. As a possible alternative to these low-efficiency and spatial resolution bubble detectors, we propose a detection system of a ZnS(Ag) scintillator coupled with photographic film. Similar to bubble detectors, photographic film can be pre-loaded prior to an inspection and offers excellent resolution. As a preliminary experiment, a light-tight box containing the 1’’ diameter Eljen-410 fast neutron detector in direct contact with the film was placed 1 m away from a deuterium-tritium (D-T) generator at the Princeton Plasma Physics Laboratory (PPPL). In a series of experiments, the target was exposed with one half of the detector covered by a polyethylene block for contrast. The results show that the side covered by poly had approximately 30% lower intensity as compared to the uncovered side. Image intensity versus exposure time shows good agreement with the slope of the characteristic curve of the film. The proposed method could present another pathway toward a practical and robust system for nuclear warhead verification.