Evaluation of the effect of the missing angles, and the choice of algorithm for the reconstruction. Left: reconstructed images of the sample at room pressure and temperature after the experiments and analyses of the iron beads. Top: from a tomogram collected ex situ, outside the PE press and reconstructed by the mean of FBP algorithm; middle: from a tomogram collected in situ and reconstructed by the mean of FBP algorithm; bottom: reconstructed by the mean of ART algorithm. Right: analyses of the sharpness of the images by measuring the intensity profile and their first derivative. The red line in the image at the top indicates the profile line used for the analyses. The white scale bars represent 500 µm.