Although the principles of XRF are straightforward, interpreting the data is more
There are four key factors influencing the signal detected
Alloy Composition and metallography
Segregation of an alloying element may be significant in particularly Pb which is
insoluble in copper alloys in the solid state, and solidifies at the interdendritic
boundary in the as-cast state and at grain boundaries in annealed structures.
Factor 2 Penetration depth and signal depth.
Although the primary X-ray beam is powerful it penetrates to a depth of about 10-15
microns, depending on accelerating voltage and density of the material being analysed.
The effective return signal derives from less depth as the secondary x-rays generated
by the deepest penetrating primary beam’s interaction with the sample do not reach
the detector due to matrix effects on the journey towards the detector. Monte-Carlo
modelling can be used to demonstrate this.