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Protecting sensitive information in an imaging system is perhaps one of the most difficult challenges in a dismantlement verification regime. An image will almost certainly contain highly sensitive information, and storing a comparison image will almost certainly violate a cardinal principle of information barriers that no sensitive information be stored in the system. While in principle some features of the image could be reduced to a few parameters suitable for an attribute, in practice that might also have undesirable features. For example, reducing the measurement to an attribute such as defined shape and X-ray transmission of an edge might reveal sensitive information relating to shape, size, and material composition. PNNL is currently evaluating a dual mode imaging (DMI) technique in which images from active (conventional) radiography and passive (auto) radiography are used as test and comparison images. Since these images are dynamically generated behind the information barrier, each can be highly detailed and not disclose sensitive information. This talk will concentrate upon the interplay of imaging information, possible image attributes, and information barriers; a companion paper by Robinson et al. will concentrate upon the technical work performed to date. This project has been supported by the US Department of Energy/Laboratory Directed Research and Development program. [ABSTRACT FROM AUTHOR]

The level of detail discernable in imaging techniques has generally excluded them from consideration as verification tools in inspection regimes where sensitive information may be present. Imaging may significantly advance verification efforts if it can be made sufficiently robust to operate behind an information barrier. One of the major drawbacks to using imaging techniques is the perceived need to have a comparison image. Since the comparison image is sensitive, storing it in a measurement system violates a cardinal rule of information barrier design. We have developed methods that eliminate the need to store a sensitive image, and these methods might be suitable for applying imaging techniques to verification problems. This paper describes the development of combined active (conventional) radiography and passive (auto) radiography techniques for imaging sensitive items assuming that comparison images cannot be furnished. Three image analysis algorithms are presented, each of which reduces full image information to non-sensitive feature information and ultimately is intended to provide only a yes/no response verifying features present in the image. These algorithms are evaluated on both their technical performance in image analysis and their application with or without an explicitly constructed information barrier. [ABSTRACT FROM AUTHOR]

Neutron detection is an essential aspect of interdiction of radiological threats for national security purposes, since plutonium, a material used for nuclear weapons, is a significant source of fission neutrons. Radiation portal monitoring systems, of which there are thousands deployed for homeland security and non-proliferation purposes, currently use ³He gas-filled proportional counters for detecting neutrons. Because of the high usage of ³He for neutron scattering science and national security, the supply has dwindled, and can no longer meet the demand. Consequently, a replacement technology for neutron detection is required in the very near future. [ABSTRACT FROM AUTHOR]