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Recently, there has been a rapid rise in experiential research investigating the potential of exploiting magnetic induction tomographic techniques to improve security, develop industry, and enhance medicine. This investigation explored the functionality of a fully automated magnetic imaging system able to capture 2-D images of featured metallic objects in unshielded and beneath conductively shielded configurations. Images were captured using a programmable x–y stage that moved objects relative to, and when magnetically coupled with, a stationary induction sensor coil; thus, position-resolved measurements of variations in sensor inductance (L) clearly defined the features of conductive objects and distinguished different material types. This investigation concentrated first on exploring the system’s ability to distinguish different metals from images that represented proportional conductivity maps, and second, on the effects that a range of shielding conductivity materials had on resultant image quality and resolution. This investigation has provided a greater understanding when assessing potential capability improvements that magnetic induction tomographic techniques could offer a security and/or industrial application. [ABSTRACT FROM PUBLISHER]

Magnetic induction tomography is a noncontact electromagnetic imaging technique that has potential applications in security, industry, and medicine. This paper describes an automated setup developed to image metallic objects. The instrument employs a pair of coils in the Helmholtz configuration for the driving field and a planar array of 400 sensor coils. The sample object is imaged via phase variation measurements between the driver and sensor coils' potential difference, due to inductive coupling between the coils and sample object. The imaging system is automated via LabVIEW. A multiplexer with 400 channels automatically connects each sensor coil to a dual-phase lock-in amplifier, so that measurements of voltage phase-difference between the sensor and driver coils could be taken. These measurements were used to generate an image of the sample object. The planar geometry of the sensor coil array makes the system scalable to a full 3-D imaging system, by simply adding two more driver and sensor assemblies orthogonally to the existing one. However, this requires the ability to image objects at a finite distance from the array plane. An experiment was conducted to explore the imaging capability for various heights of sample-lift-off above the array. This proved that the system is scalable to a full 3-D imaging system. [ABSTRACT FROM AUTHOR]

Combating illicit trafficking of Special Nuclear Material may require the ability to image through electromagnetic shields. This is the case when the trafficking involves cargo containers. Thus, suitable detection techniques are required to penetrate a ferromagnetic enclosure. The present study considers techniques that employ an electromagnetic based principle of detection. It is generally assumed that a ferromagnetic metallic enclosure will effectively act as a Faraday cage to electromagnetic radiation and therefore screen any form of interrogating electromagnetic radiation from penetrating, thus denying the detection of any eventual hidden material. In contrast, we demonstrate that it is actually possible to capture magnetic images of a conductive object through a set of metallic ferromagnetic enclosures. This validates electromagnetic interrogation techniques as a potential detection tool for National Nuclear Security applications. [ABSTRACT FROM AUTHOR]