The second step is to calculate
the element concentration using a combination of the fundamental
parameter (FP) method and the reference method.
The FP is a method of theoretical calculation of the fluorescence
X-ray intensity on the basis of the instrument’s characteristics
parameters and physical fundamental parameters
including the photoelectric absorption coefficient, mass
absorption and fluorescence yield rate. The reference method
allows more accurate analysis providing some reference standards
of known composition. This method has the advantage
to combine the data collected from the measured spectra of
the known references and the powerful FP method calculation
to adjust the instrument parameters (Jeol, 2005; Al-Eshaikh
and Kadachi, 2005).