A beam hardening correction for X-ray microtomography

We propose a correction of the transmitted intensities in X-ray microscopy allowing improved quantification for polychromatic sources, particularly in tomographic reconstruction. The correction is based on the application of Beer's law for each energy present in the source spectrum. Knowledge of the source spectrum and the average specimen composition are used. The correction is demonstrated on a chemically homogeneous specimen (a glass capillary filled with glass beads) and on a polyphasic oil reservoir rock sample. In the former, detection of 20 mu m defects is demonstrated. In the latter, different minerals, quartz, feldspath and kaolinite, can be discriminated and their distributions mapped. (C) 1997 Elsevier Science Ltd.