XRF can be used for elemental analysis for different sample size. In dependence of the excitation area the analysed volume will differ. Larger spot size allows averaging of slightly non-homogeneous samples, smaller spot sizes can be used to deter-mine the position sensitive elemental composition of non-homogeneous samples or their element distribution. The information depth will not influenced by the spot size. This is dependent only on energy of fluorescence radiation and their matrix absorption. Parameters that are important for selection the best spot size are mainly
- Analytical task and in case of using collimators
- Required accuracy for the analysis.