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Focal construct geometry is the scientific and technological basis of a patented innovation for high-speed acquisition of angular dispersive X-ray diffraction data with enhanced intensity. The theoretical considerations underlying FCG were first presented by Rogers et al. (2010). FCT is a very promising emerging technique with established proof-of-principle, demonstrating its capabilities to produce conventional diffractograms with higher intensity than traditional X-ray diffraction techniques. FCT’s uniqueness and advantages lie within its hollow conical beam arrangement that ‘focuses’ multiple diffraction maxima into single condensation foci, along a primary axis, with significantly enhanced intensity. Further, FCT's halo beam is employed to absorption tomography. 

Further reading

1) ROGERS, K., EVANS, P., ROGERS, J., CHAN, J. W. & DICKEN, A. 2010. Focal construct geometry - a novel approach to the acquisition of diffraction data. J. Appl. Cryst., 43, 264-268.

2) EVANS, P., ROGERS, K., CHAN, J., ROGERS, J. & DICKEN, A. 2010. High intensity x-ray diffraction in transmission mode employing an analog of Poisson's spot. Applied Physics Letters, 97, 204101-1 - 204101-3.
3) EVANS, P., ROGERS, K., DICKEN, A., GODBER, S. & PROKOPIOU, D. 2014. X-ray diffraction tomography employing an annular beam. Optics Express, 22, 11930-11944.

4) ELARNAUT, F., EVANS, J. P. O., DOWNES, D., DICKEN A. J., GODBER S. X., & ROGERS K. D. 2017. Sporadic absorption tomography using a conical shell X-ray beam. Optics Express, 25 (26), 33029-33042.

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