X-Ray Imaging (XRI) has a fundamental role in medicine and security, and is instrumental in the automotive, aerospace, pharmaceutical industries and in manufacturing in general. Cultural heritage relies on XRI, as do materials science, biology, and many other scientific fields. Through our established collaboration between Nikon X-Tek Systems (NXTS, Nikon's UK based x-ray division) and UCL, we are targeting the next paradigm shift in XRI. Our vision is that this will involve the incorporation of phase effects in the image formation process ("Phase-based" XRI) coupled with energy-resolved ("colour") XRI and new data reconstruction and interpretation algorithms. "Colour" XRI could be seen as the x-ray equivalent of the transition from black and white to colour photography, meaning a much wider spectrum of information can be obtained from the imaged sample. Phase-based XRI enables contrast increases of up to two orders of magnitude, thus allowing the detection of features classically considered "x-ray invisible".
Our vision is to marry UCL's world-class research and expertise on phase-based XRI (see here), inverse problems and nanofabrication with NXTS's innovation on scatter analysis, image reconstruction and colour x-ray imaging in order to achieve the next step change in XRI technology, with the UK industrial and academic communities firmly at the centre. This will deliver transformative solutions that are practicable in an industrial context and beneficial to a wide user base, while also enabling new science. Our ambition is to replace conventional attenuation based XRI with energy-resolved, phase-based technology combined with scatter retrieval and novel algorithms in most application areas.
At synchrotron facilities, UCL researchers have used phase-based XRI to image rocks, metals, tissues, animals, humans, cells, foams, fabrics, batteries, manufacturing processes, food, and heritage artefacts. They have done this statically and dynamically, in situ and in operando, in vivo and ex vivo, invariably detecting key features that were invisible to other methods. Making this available through standard, lab-size machines would be nothing short of a revolution, leading to economic and societal impact through the multi-disciplinary applications, making NXTS the commercial leader in the field, and cementing UK's leading research status. In our vision this will be strengthen even further by its combination with "colour" imaging, and with new ways of handling scattered radiation such that the "structured" scatter signal leading to additional information is exploited, while the uniform background that limits image contrast and therefore detail visibility is rejected.
We will pursue this vision through a combination of modelling and experimental work. Using experimentally validated simulation software developed jointly by the UCL and NXTS teams, we will model experiments before they are carried out, compare simulated and experimental results, refine models and setups until all discrepancies are clarified, and only then proceed to the next step. This will enable us to develop systems where i) we keep all parameters under control and have full understanding of their effects and implications, and ii) we can steer the design towards effective solutions to specific problems. Cutting-edge nanofabrication methods (available at UCL's Photonic Innovations Lab and London Centre for Nanotechnology) will enable the development of beam modulators that allow the exploitation of phase effects with the conventional x-ray sources routinely used by NXTS.
We will apply the novel technologies to a range of high-impact applications, including non-destructive testing of composite materials and additive manufacturing processes and products, biomaterials and tissue-engineered organs, digital histology, improved detection of concealed explosives and forensics.
Our partnership is supported by EPSRC (Grant EP/T005408/1).