Comparison of different excitation methods for X-ray spectral analysis: the case of synchrotron radiation

Different excitation means, protons, photons and electrons (PIXE, XRFA, and EPMA, respectively) have previously been compared with regard to the figur es of merit, i.e. detection power, precision and accuracy. The aim in this article is to compare synchrotron radiation SR as another excitation method with the methods mentioned above. From this point of view the evaluation o f(SR) was missing as an again independently optimized excitation method and was based as previously on practical problems of trace analysis, in this c ase on the determinations of traces in lead. The experiment has been perfor med with thick homogeneous samples of lead, the same samples already used i n the former work, so that a direct comparison is possible. The calculation of the figures of merit is based on the measurements of the blank values a nd their relative standard deviation far the detection Limit and on the ran dom errors for the precision. Regarding the thick homogeneous target of lea d XRFA still turns out to be the best method, whereas Synchrotron X-Ray Flu orescence SY-XRF compares favorably, at least for larger atomic numbers Z. Even PIXE is inferior to (SY-XRF) in the case of larger Z; when information on the lateral distribution of the elements is of interest, PIXE is indisp ensable.