To obtain maximum accuracy during the measurement, the specimens'
region of interest had to be positioned exactly on the rotation
axis of the rotary table. To obtain comparable results, all the measurement
parameters were kept constant. A voxel of about 25 μmside length
was obtained. The current intensity and voltage of the X-ray source
were selected after several trials and set to 200 μA and 120 kV,
respectively, leading to an X-ray power of 24W. Thus, a long exposure
(2 s) to the X-rays is required to attain a measurable X-ray absorption
on each 2D radiographic image. The reconstruction of the 3D object by
means of three processing steps (data preparation, filtering, back projection)
required several 2D radiographic images of different orientations
for one complete rotation of the object. For all the conducted
measurements, 1600 rotational steps with 8 radiographic images per
orientation were captured to increase the quality of the final 2D image.