Element specific X-ray fluorescene microtomography
X-ray fluorescence is widely known as an element-specific scanning analytic tool. It is used in many fields of science and technology and has given major new insights into different problems. The relatively large penetration depth of x rays into matter makes them ideally suited for tomography. The combination of x-ray fluorescence analysis and scanning microtomography, hereafter called x-ray fluorescence microtomography, has been further developed and improved in this work. Employing the newly developed refractive x-ray lenses at a third generation synchrotron source the spatial resolution of this technique could be reduce to a micrometer. The fluorescence radiation that leaves the sample and can be detected from outside suffers absorption on its way to the detector. This problem of absorption is treated in this work, too and technical improvements of the setup are outlined. These improvements reduce the absorption of the fluorescence radiation. This in turn improves the signal to noise ratio of the fluorescence radiation and lowers the detection limit. Moreover, a tomographic reconstruction algorithm is described which is especially designed for x-ray fluorescence tomography. This algorithm takes into account the absorption of the fluorescence radiation within the sample. Some example applications are described to illustrate the success and power of this method as well as its advantages over other microanalytic methods. Also, the possible use of x-ray fluorescence microtomography in a laboratory is assessed. Besides this, the work briefly introduces into interactions of x rays with matter, into the concepts of the detectors that were used, and into the working principle of the refractive lenses.
info:eu-repo/classification/ddc/530, Fluoreszenzanalyse, Charakteristische Röntgenstrahlung, Tomographie, Röntgenoptik, Physik, x-ray fluorescence scanning tomography microanalysis tomographic reconstruction peak deconvolution
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