Main sources contributing to uncertainty in XRF analysis

The major contributions to uncertainty of the results in XRF analysis are often the following:

• Uncertainty due to counting statistics: Owing to the statistical nature of the measured signal, the standard deviation of the peak area N can be assumed as √N. In the case of spectrum fitting, the uncertainty due to the quality of peak fit must be accounted as well. This source becomes one of the largest in the case of low counting statistics.
  
  
• When using Certified Reference Materials for the calibration of the model, the uncertainty of the calibration is affected by the uncertainty of the certified values of the CRMs.
  
  
• Depending on the procedure followed to estimate the effective sample attenuation, the uncertainty of the attenuation correction can be significant.

Other sources must be carefully evaluated in each analytical procedure.