Internal elemental microanalysis combining x-ray fluorescence, Compton and transmission tomography

Abstract

Conventional x-ray transmission tomography provides the spatial distribution of the absorption coefficient inside a sample. Other tomographic techniques, based on the detection of photons coming from fluorescent emission, Compton and Rayleigh scattering, are used for obtaining information on the internal elemental composition of the sample. However, the reconstruction problem for these techniques is generally much more difficult than that of transmission tomography, mainly due to self-absorption effects in the sample. In this article an approach to the reconstruction problem is presented, which integrates the information from the three types of signals. This method provides the quantitative spatial distribution of all elements that emit detectable fluorescent lines (Z⩾15 in usual experimental conditions), even when the absorption effects are strong, and the spatial distribution of the global density of the lighter elements. The use of this technique is demonstrated on the reconstruction of a grain of the martian meteorite NWA817, mainly composed of low Z elements not measured in fluorescence and for which this method provides a unique insight. The measurement was done at the ID22 beamline of the European Synchrotron Radiation Facility.

Determination of the elemental distribution in human joint bones by SR micro XRF

“…However, in the tomographic mode exact conclusions on the distribution of Zn and Pb are very complicated, which is mainly due to the missing Ca information due to self absorption. A way to overcome this problem would be to perform combined x-ray fluorescence, Compton and transmission tomography as proposed by Golosio et al 37 By applying this method it would be possible to obtain a quantitative spatial distribution of all the detectable elements in the sample, even in cases of strong absorption effects. Although the results presented are very promising, the reconstruction algorithms are more complicated.…”

Element-to-tissue correlation in biological samples determined by three-dimensional X-ray imaging methods

“…26,27 In general, micro-XRF CT involves long measuring times and challenging data treatment, making a 3D determination/visualisation of the elemental distributions within a given sample a complex task. In contrast, confocal micro-XRF does not require a tomographic reconstruction procedure, and it enables the local analysis of arbitrary sub-volumes inside the sample.…”

Synchrotron X-Ray Microfluorescence and Microspectroscopy: Application and Perspectives in Materials Science

“…The increasing interest and demand of several research fields also motivate the development of new methods at ID22, such as quantitative µ-X-ray fluorescence tomography [41] or X-ray holography [42].…”