Meaning
Mathematical algorithms calculate the elemental composition of a sample by modeling the physical interactions between x-rays and atoms. Use of fundamental parameters allows for the quantification of flame retardants or heavy metal stabilizers in polymers without the need for a large library of physical standards.
Matrix Correction
Absorption and enhancement effects are accounted for by using known physical constants such as photo electric cross sections and fluorescence yields. This method ensures that the fundamental parameters approach remains accurate even when the base resin density changes. Overlap between element peaks is resolved through iterative calculation until the calculated spectrum matches the measured intensities perfectly.
Quantitative results are achieved by balancing the observed x-ray fluorescence against the theoretical probability of atom excitation within the polymer matrix.
Analysis Speed
Calibration time is reduced because the software relies on theoretical physics rather than empirical curves. When switching from a polyethylene carrier to a polyamide one, fundamental parameters adjust for the change in background scattering automatically. This flexibility is essential for screening incoming regrind for prohibited substances like lead or cadmium before the material enters the production line.
Measurement Boundary
Energy levels of the x-ray source must be sufficient to excite the K or L shells of the target elements. Sensitivity for light elements such as magnesium or aluminum is lower due to their low fluorescence yield and high air absorption. Fundamental parameters cannot compensate for samples that are thinner than the critical depth of the x-ray beam.
