X-rays, absorption characteristic

Frequently, these qualitative results are summarized in publications with semi-quantitative qualifiers, such as abundant , minor , and trace on the basis of the relative intensities of the peaks. Intuitively, one would expect the intensity of the diffraction peak from a particular mineral to be simply related to that mineral s abundance. However, it has long been recognized that this relationship is not straightforward. In a mixture of minerals, the peak geometry is affected by not only the relative and absolute abundance of the particular mineral and its crystallinity, but also by the X-ray absorption characteristics (termed the mass absorption coefficient) and particle size of the other minerals, and the amount of amorphous material in the sample. The end result is that the intensity relations among peaks for a multicomponent mixture can be very complicated. 

The X-ray computed tomography, commonly abbreviated as X-ray CT, is a nondestructive testing method used to analyze the internal structure of objects. During testing, the examined object is X-rayed from different angles and the resulting set of projections is reconstructed to a three-dimensional volume (Fig. 7.1). The X-ray CT technique is based on the differentiation of different materials by their dissimilar X-ray absorption characteristics. After the penetration of the sample, the rays exhibit the transmitted intensity that is defined by the intensity of radiation /, the absorber thickness h, and the attenuation coefficient // according to the equation ... 

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