I PB X-ray and IR spectrometry Quantitative - PowerPoint PPT Presentation

I I PB X-ray and IR spectrometry Quantitative Röntgenfluoreszenzanalyse Woran wir g lauben und was wir wissen. Quantitative X-Ray Fluorescence Analysis In what we believe and what we know. Burkhard Beckhoff PTB Berlin, Germany

X-ray spectrometry methodologies: I I PB reference-based versus reference-free approaches X-ray and IR spectrometry reference material related technique reference-free technique XRF excitation channel based on well known calibration based on calibrated instrumen- specimens or reference materials tation and fundamental parameters unknown detection efficiency absolute detection efficiency unknown spectral unknown response functions and response functions distribution and / or known spectral W W unknown intensity d d distribution and known intensity fluorescence fluorescence F Y F Y radiation radiation calibration fundamental specimen specimen specimens parameters well-known knowledge of compensation for laboratory instruments synchrotron radiation the parameters missing knowledge

I I PB Synchrotron radiation based x-ray spectrometry X-ray and IR spectrometry XRF excitation channel XRS excitation channel: XRS detection channel: XRF detection channel absolute detection efficiency and response functions well-known spectral distribution well-known d W and a well-known radiant power solid angle fluorescence F Y radiation PTB capabilities:  characterized beamlines fundamental parameters specimen  calibrated photodiodes knowledge of the parameters  calibrated diaphragms transmission  calibrated Si(Li) detectors measurements absorption correction factors JAAS 23 , 845 (2008)

I I PB Quantitative XRF – primary excitation (Sherman equation) X-ray and IR spectrometry instrumental parameters fundamental parameters  mass absorption coefficien t ...   Φ s 0 E 0   τ (sub)shell photo - electric absorption ... Φ d E i , shell i 0 cross section   in  out fluorescen ce yield of (sub)shell ... t i , shell dt d transition probabilit y of fluorescen ce line f ... i , line  density s ... W       1    Φ Φ d E E f E   i , line 0 0 0 i , line i , shell i , shell 0 4 sin in             1 E E            0 i     1 exp d         E E   sin sin      0 i in out   sin sin in out M. Kolbe Phys. Rev. A 86 , 042512 (2012)

I I PB Quantitative XRF – Sherman equation for thin layer samples X-ray and IR spectrometry I 0, F 0 , E 0 I f B. Beckhoff, J. Anal. At. Spectrom. 23 , 845 (2008) substrate sample m i /F = mass deposition R. Unterumsberger et al., Anal. Chem. 83 , 8623 (2013) E 0 = photon energy of excitation radiation E f = photon energy of fluorescence radiation I f = intensity of fluorescence radiation in d W I 0 = intensity ( photons/s ) of excitation radiation d W = solid angle ( sr ) of fluorescence detection F 0 = beam profile area ( mm² ) of excitation radiation

I I PB Quantitative XRF – Sherman equation for thin layer samples X-ray and IR spectrometry B. Beckhoff, J. Anal. At. Spectrom. 23 , 845 (2008)

I I PB Quantitative XRF – Sherman equation for thin layer samples X-ray and IR spectrometry R. Unterumsberger et al., Anal. Chem. 83 , 8623 (2013)

I I PB Quantitative XRF – influence of the beam profile X-ray and IR spectrometry I 0, F 0 I 0, F‘ 0 Assumption: F 0 < F‘ 0 I f I‘ f Consequence: substrate substrate 1. A: I f < I‘ f 1. B: I f = I‘ f sample 1. C: I f > I‘ f m i /F = mass Yes No deposition E 0 = photon energy of excitation radiation E f = photon energy of fluorescence radiation I f = intensity of fluorescence radiation in d W I 0 = intensity ( photons/s ) of excitation radiation d W = solid angle ( sr ) of fluorescence detection F 0 = beam profile area ( mm² ) of excitation radiation

I I PB Quantitative XRF – influence of the beam intensity X-ray and IR spectrometry I 0, F 0 I‘ 0, F 0 Assumption: I 0 < I‘ 0 I f I‘ f Consequence: substrate substrate 2. A: I f < I‘ f 2. B: I f = I‘ f sample 2. C: I f > I‘ f m i /F = mass Yes No deposition E 0 = photon energy of excitation radiation E f = photon energy of fluorescence radiation I f = intensity of fluorescence radiation in d W I 0 = intensity ( photons/s ) of excitation radiation d W = solid angle ( sr ) of fluorescence detection F 0 = beam profile area ( mm² ) of excitation radiation

I I PB Quantitative XRF – influence of the sample thickness X-ray and IR spectrometry I 0, F 0 I 0, F 0 Assumption: increase of sample thickness I f I‘ f Consequence: substrate substrate 3. A: I f < I‘ f 3. B: I f = I‘ f sample 3. C: I f > I‘ f m i /F = mass Yes No deposition E 0 = photon energy of excitation radiation E f = photon energy of fluorescence radiation I f = intensity of fluorescence radiation in d W I 0 = intensity ( photons/s ) of excitation radiation d W = solid angle ( sr ) of fluorescence detection F 0 = beam profile area ( mm² ) of excitation radiation

I I PB Quantitative XRF – influence of the sample size X-ray and IR spectrometry I 0, F 0 I 0, F 0 Assumption: increase of sample diameter I f I‘ f Consequence: substrate substrate 4. A: I f < I‘ f 4. B: I f = I‘ f sample 4. C: I f > I‘ f m i /F = mass Yes No deposition E 0 = photon energy of excitation radiation E f = photon energy of fluorescence radiation I f = intensity of fluorescence radiation in d W I 0 = intensity ( photons/s ) of excitation radiation d W = solid angle ( sr ) of fluorescence detection F 0 = beam profile area ( mm² ) of excitation radiation

I I PB Quantitative XRF – influence of the sample position X-ray and IR spectrometry I 0, F 0 I 0, F 0 Assumption: sample position influence I f I‘ f Consequence: substrate substrate 5. A: I f < I‘ f 5. B: I f = I‘ f sample 5. C: I f > I‘ f m i /F = mass Yes No deposition E 0 = photon energy of excitation radiation E f = photon energy of fluorescence radiation I f = intensity of fluorescence radiation in d W I 0 = intensity ( photons/s ) of excitation radiation d W = solid angle ( sr ) of fluorescence detection F 0 = beam profile area ( mm² ) of excitation radiation

I Quantitative XRF – influence of the incident angle I PB X-ray and IR spectrometry I 0, F 0 Assumption: more I 0, F 0 shallow incident I f I‘ f angle Consequence: substrate substrate 6. A: I f < I‘ f 6. B: I f = I‘ f sample 6. C: I f > I‘ f m i /F = mass Yes No deposition E 0 = photon energy of excitation radiation E f = photon energy of fluorescence radiation I f = intensity of fluorescence radiation in d W I 0 = intensity ( photons/s ) of excitation radiation d W = solid angle ( sr ) of fluorescence detection F 0 = beam profile area ( mm² ) of excitation radiation

I I PB Quantitative XRF – influence of the angle of observation X-ray and IR spectrometry I 0, F 0 I 0, F 0 Assumption: more shallow observation I f angle I‘ f Consequence: substrate substrate 7. A: I f < I‘ f 7. B: I f = I‘ f sample 7. C: I f > I‘ f m i /F = mass Yes No deposition E 0 = photon energy of excitation radiation E f = photon energy of fluorescence radiation I f = intensity of fluorescence radiation in d W I 0 = intensity ( photons/s ) of excitation radiation d W = solid angle ( sr ) of fluorescence detection F 0 = beam profile area ( mm² ) of excitation radiation

I I PB Quantitative XRF – influence of exciting photon energy X-ray and IR spectrometry I 0, F 0 , E 0 I 0, F 0 , E‘ 0 Assumption: E 0 < E‘ 0 I f I‘ f Consequence: substrate substrate 8. A: I f < I‘ f 8. B: I f = I‘ f sample 8. C: I f > I‘ f m i /F = mass Note, that E 0 > E K-abs, sample Yes No deposition E 0 = photon energy of excitation radiation E f = photon energy of fluorescence radiation I f = intensity of fluorescence radiation in d W I 0 = intensity ( photons/s ) of excitation radiation d W = solid angle ( sr ) of fluorescence detection F 0 = beam profile area ( mm² ) of excitation radiation

I I PB Quantitative XRF – influence of experimental parameters X-ray and IR spectrometry Yes No Yes No Yes No 1. A: 4. A: 7. A: 8 0 5 I 0, F 0 , E 0 4. B: 7. B: 1. B: 7 7 25 6 I f 4. C: 7. C: 1. C: 2 10 11 2. A: 5. A: 5 14 8. A: 15 5. B: 2. B: 3 0 8. B: 4 2. C: 5. C: 8. C: 4 20 4 substrate Yes No 6. A: 3. A: 13 11 sample 3. B: 6. B: 0 7 m i /F = mass 6. C: 3. C: 9 9 deposition Yes No Yes No E 0 = photon energy of excitation radiation E f = photon energy of fluorescence radiation I f = intensity of fluorescence radiation in d W I 0 = intensity ( photons/s ) of excitation radiation d W = solid angle ( sr ) of fluorescence detection F 0 = beam profile area ( mm² ) of excitation radiation