Tomographic energy-dispersive diffraction

Beale AM, Jacques SDM, Bergwerff JA, Barnes P, Weckhuysen BM. Tomographic energy dispersive diffraction imaging as a tool to profile in three dimensions the distribution and composition of metal oxide species in catalyst bodies. Angew Chem Int Ed. 2007 46 8832. 

IR microspectroscopy [12], and UV-Vis-NIR DR microspectroscopy [9,12-15] as invasive techniques and tomographic energy-dispersive diffraction imaging (TEDDI) [16] and magnetic resonance imaging (MRI) [17-25] as noninvasive techniques. In what follows, we will discuss the application of these methods for catalyst preparation studies, illustrating their possibilities and limitations. 

TEDDI tomographic energy-dispersive diffraction imaging... 

Fig. 4. Direct tomographic, energy-dispersive X-ray diffraction imaging system. Suitcase enters device at left of Figure where spatial landmarks for registration purposes are measured by pre-scanner. In main housing centre-right of Figure, a primary cone-beam executes a meander scan, either of a region-of-interest or suitcase in its entirety. Illustration courtesy of GE Security, Germany.

Further work in the energy-dispersive CSCT area is needed to determine the limits to performance set by photon noise and reconstruction artefacts. Comparison of the plastic profiles of Fig. 20 with the diffraction profile of TNT (Fig. 5) derived from a direct tomographic energy-dispersive XDI device shown in Fig. 4 suggests that the latter has currently an advantage owing to its avoidance of reconstruction artefacts. 

G Harding (2005) The design of direct tomographic, energy-dispersive x-ray diffraction imaging (XDI) systems. SPIE 59230R. 

Fig. 17. Two-dimensional generic cross-section for energy-dispersive direct tomographic X-ray diffraction imaging.

---