4. Analytical profiling

4.1 Basic parameters

Since it allows us to measure composition as a function of spraying time, i.e. the depth of the zone analyzed in the sample, ion analysis is an ideal means of determining variations in concentration as a function of distance from the surface. The aspects discussed above concerning species identification, detection limits and quantitative expression of concentrations are of course also relevant to depth analysis.

The problem is the precision of the concentration (or signal)-depth relationship, i.e. the depth resolution of the analysis. From a definitional point of view, we must not confuse four different, albeit related, notions:

• for certain analysis methods (e.g. RBS, ERDA, electron beam analysis...