TREATMENT OF ROUGHNESS AND CONCENTRATION GRADIENTS IN TOTAL REFLECTION X-RAY-FLUORESCENCE ANALYSIS OF SURFACES

Total Reflection X-ray fluorescence (TXRF) spectrometry, a new technique for surface and layer analysis, was originally confined to ideal smooth interfaces. In practice, however, one has to cope with more or less rough surfaces. Therefore, modelling calculations have been conducted to consider the consequences of residual roughness on the fluorescence signal at grazing incidence. The model used was verified experimentally on surfaces which exhibit peak-to-valley roughnesses ranging from 5 to 4000nm. In addition, concentration changes occuring in the zone of roughness in the surface layer of a high grade steel after exposure to nitric acid were determined.