Comunicazione
Development and comparison of spectral X-ray imaging systems using synchrotron radiation.
Perion P., Brombal L., Delogu P., Di Trapani V., Menk R.H., Oliva P., Arfelli F.
Spectral $K$-edge X-ray imaging takes advantage of the sharp rise in the attenuation coefficient of high-$Z$ elements at their $K$-edge. This technique requires the acquisition of images at multiple energies below and above the target $K$-edges to provide separate and quantifiable density maps for each element. In this contribution, the performances of two spectral imaging systems, implemented at a synchrotron facility, are assessed and compared. The first system is diffraction-based, relying on an energy-dispersive bent-Laue crystal which produces a continuous energy spectrum. The second one includes an energy-resolved X-ray photon counting detector, which provides spectral information by implementing two energy thresholds. Samples containing contrast elements relevant for biomedical imaging in different dilutions were used to evaluate the sensitivity of both systems. All images were acquired in tomographic mode. Sensitivity to very small concentrations (0.5 mg/ml) was reached. Moreover, simultaneous tomographic imaging of the $K$-edges of iodine, xenon, and barium, owing to the achievement of a large energy bandwidth over a large field of view is being demonstrated for the first time.