X-ray Tomography Application to 3D Characterization of Membranes

Tomography by X-ray is a nondestructive technique for the characterization of objects. Like all the tomographies, it is a question of obtaining 3D information on the internal and/or external structure of the observed object. This technique thus makes it possible to observe and to inspect objects (search for defects, fractures, etc.) or to measure characteristic dimensions (thickness, size of pores, porosity, etc). This chapter covers only the tomography of absorption, which is the simplest technique. More sophisticated methods exist such as phase contrast tomt raphy [1, 2j. 

The absorption of X-rays of wavelength A, by a material is described by the Beer-Lambert law  

Equation (10.1) can be rewritten in the form of Equation (10.2). This equation shows that, by standardizing the intensity transmitted by the incident photons, it is possible to determine the integral of p. along the crossed thickness. As the object 

The linear attenuation coefficient fi) is calculated, for a given wavelength, using Equation (10.3)  

According to this equation, the linear attenuation coefficient p. is proportional to the density of the medium and the atomic composition of medium (Z with the power 4) for a given energy E. 

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