Explosive detection using pixellated X-ray diffraction (PixD)

A novel, pixellated, energy-resolving X-ray detector has been utilised to simultaneously combine angular and energy dispersive X-ray diffraction (XRD). This approach allows a system to measure XRD data using the benefits of both approaches. Data acquisition is fast, and the system contains no moving parts, making it ideal for applications in security, particularly for the detection of explosive materials hidden within packages or baggage. Explosive samples supplied by the Centre for Applied Science and Technology, U.K. were examined using the pixellated diffraction technique, and the XRD data were compared with those from inert materials typically found inside luggage. A method of processing the data was developed, which greatly reduces the amount of data outputted from the detector whilst preserving the angular and energy resolution. Using principal component and discriminant analyses, a model was developed which predicts the correct classification of an unknown sample as either ``explosive'' or ``inert'' for data with acquisition times as low as one second.