X-ray screening can be used to aid in the detection of a variety of threats, including items such as explosives and narcotics. Conventional x-ray imaging provides limited means of distinguishing between different materials. Gratings-based phase contrast x-ray imaging provides images reflecting three distinct materials signatures: absorption, similar to conventional x-ray imaging; phase contrast, proportional to electron density variations; and dark field, which can be related to material texture. These additional signatures may enhance the ability to distinguish materials in x-ray images, leading to detection improvements. Here we discuss considerations for system design and improved detection: approach to measurements at relevant energies for security screening, signature studies of explosives and opioids as well as common benign materials, and development of a prototype screening system.
|