New tomographic methods using X-ray tubes

Abstract

Different kinds of images of the section of a sample can be deduced from the interaction of X-rays with matter: 1. (1)|When two X-ray beams are employed, the energies of which closely bracket a photoelectric discontinuity of an element in the sample, then the difference of two images carried out with the pair of X-rays is only sensitive to the element itself. This kind of tomography, called “differential tomography”, gives the distribution of the element in the section. 2. (2)|Fluorescent X-rays emitted by the voxel identified by the intersection of the collimated incident beam with the collimated secondary beam can be mapped versus the x – y position of the voxel: an image can be obtained (called XRF-tomography) giving the distribution of all fluorescent elements. 3. (3)|When the diameter of the beam in the transmission tomography is reduced to the order of magnitude of microns, then a “microtomography” is obtained, in which the geometrical resolution is of the same order of magnitude.