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Review of φ(ρz) curves in electron probe microanalysis
Author(s) -
Riveros José,
Castellano Gustavo
Publication year - 1993
Publication title -
x‐ray spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
eISSN - 1097-4539
pISSN - 0049-8246
DOI - 10.1002/xrs.1300220103
Subject(s) - ionization , electron , gaussian , binary number , function (biology) , cross section (physics) , atomic physics , electron scattering , quadrilateral , physics , computational physics , mathematics , nuclear physics , ion , thermodynamics , quantum mechanics , arithmetic , evolutionary biology , biology , finite element method
Several workers have proposed different models for the ionization distribution function ϕ(ρz), involving features related to the interaction of electrons with matter, e.g. ionization cross‐section, stopping power, electron back‐scattering and mass absorption coefficients (MACs). A number of expressions have been developed for these parameters, on which the accuracy of the correction procedures depends. This paper presents a comparison among three of the more successful models for ϕ(ρz): Packwood and Brown's Gaussian model, the quadrilateral model proposed by Sewell et al. and Pouchou and Pichoir's model. In order to test these models, a set of 1547 measurements in binary samples of known composition has been complied. Several models for the ionization cross‐section have been tested, along with different expressions for the mean ionization potential J , in which the shell effect can be taken into account. In addition, two possibilities for both the MACs and the electron backscattering coefficient are available. In general, all the tested models showed similar performances. Finally, the advantages of the models related to basic principles over the mathematically optimized ones, in the shape of ϕ(ρz) or in the parameters, are considered.