  Grazing-Incidence X-ray fluorescence (GIXRF) analysis, which is closely
related to total-reflection XRF, is a very powerful technique for the in-depth
analysis of many types of technologically relevant samples, e.g. nanoparticle
depositions, shallow dopant profiles, thin layered samples or even well-ordered
nanostructures. However, the GIXRF based determination of the depth-dependent
information about the sample is usually based on a modelling of the
experimental data. This requires profound knowledge of the geometrical
parameters of the setup employed, especially the incident beam profile as well
as the detector aperture parameters. Together they determine the incident angle
dependent so-called effective solid angle of detection which must be known in
order to model any experimental data set. In this work, we demonstrate how
these instrumental parameters, which are typically not known with sufficient
accuracy, can be determined using dedicated experiments with a well-known
calibration sample. In addition, this paves the way for a full calibration of
the setup, as also information about other parameters, e.g. the incident photon
flux is gained. Here, we are using a Bruker S4 T-STAR instrument for this
demonstration but the principle can also be applied for other GIXRF setups.
