Bulk morphology of porous materials at sub-micrometer scale studied by multi-modal X-ray imaging with Hartmann masks

We present the quantitative investigation of the submicron structure in the bulk of porous graphite by using the scattering signal in the multi-modal X-ray imaging with Hartmann masks. By scanning the correlation length and measuring the mask visibility reduction, we obtain average pore size, relative pore fraction, fractal dimension, and Hurst exponent of the structure. Profiting from the dimensionality of the mask, we apply the method to study pore size anisotropy. The measurements were performed in a simple and flexible imaging setup with relaxed requirements on beam coherence.