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Reference-free X-Ray Fluorescence analysis (XRF)

Brief description of the Method

X-ray Fluorescence (XRF) analysis is based on the element specific emission of radiation upon ionization by removal of inner shell electrons. A quantitative XRF analysis requires the accurate knowledge of all experimental parameters both in the excitation and detection channels as well as of the atomic fundamental parameters involved. At PTB, the experimental parameters are well known due to the usage of calibrated instrumentation [1] (see fig. 1). This enables a reference-free quantitative XRF analysis, which is physically traceable to the SI unit system. Relevant atomic fundamental parameters can be experimentally determined or obtained from tabulated data sets.

The decisive advantage of reference-free XRF – as developed by PTB – is that it is absolutely independent of suitable calibration standards and reference materials, as these are often not available or would have to be developed and certified with great effort [1].


  • Completely reference-free quantitative analysis [1]


  • Quantitative thin layer characterization
  • Compositional analysis of bulk samples

Research Highlights

  • Thickness determination for nanolayers [2,3]
  • Depth profiling of implants [4] and nanolayers
  • Contamination analysis [5,6]
Fig. 1: Schematic set-up of reference-free XRF experiments


  1. Opens external link in new windowReference-free X-ray spectrometry based on metrology using synchrotron radiation, J. Anal. At. Spectrom. (2008) 23, 845-853
  2. Opens external link in new windowThickness determination for Cu and Ni nanolayers: Comparison of reference-free fundamental-parameter based X-ray fluorescence analysis and X-ray reflectometry, Spectrochimica Acta B (2005) 60, 505-510
  3. Opens external link in new windowCharacterization of high-k nanolayers by grazing incidence X-ray spectrometry, Materials (2014) 7(4), 3147-3159
  4. Opens external link in new windowDepth profile characterization of ultra shallow junction implants, Anal. Bioanal. Chem. (2010) 396(8), 2825-2832
  5. Opens external link in new windowReference Samples for Ultra Trace Analysis of Organic Compounds on Substrate Surfaces, Solid State Phenomena (2012) 187, 295-298
  6. Opens external link in new windowReliable quantification of inorganic contamination by TXRF, Solid State Phenomena (2012) 187, 291-294