Figure 6: The mean reconstructed attenuation coefficient in Al tubes of different diameters, scanned (a) in water (20 mm) or (b) air, with no filter and 12 um pixel size. The in-air scans were repeated at a high resolution (4 um pixel) to minimize partial volume effects (c). With no filter, BHC has no effect in correcting divergent attenuation linked to object thickness, either in air or water.