ABSTRACT
A. Diffraction Techniques X-rays have a high transmittance for carbon materials. The transmittance of electromagnetic waves depends on the mass absorption coefficient of the material, its density, and the optical pathlength. The transmittance of MoKa radiation for carbon materials of 1 mm thickness and of 1 g cm-3 in density is 95%. This transmittance is fairly large compared with electrons, indicating that X-ray techniques can provide information on the bulk structure of carbon materials. However, carbon materials absorb even X-rays mainly due to the photoelectron effect, and it is important to correct for the incoherent scattering for an accurate analysis. On the other hand, the absorption of neutrons by carbon is negligible and the incoherent scattering is minor. Although neutron diffraction is effective for structural studies, neutron facilities are very limited. Here the structural analysis of activated carbons with X-ray diffraction is described. A review on neutron scattering of carbon materials was published recently in a preceding volume [564].
