Hostname: page-component-586b7cd67f-rcrh6 Total loading time: 0 Render date: 2024-11-26T06:25:01.406Z Has data issue: false hasContentIssue false
  • English
  • Français

Theoretical and Experimental X-Ray Peak/Background Ratios and Implications for Energy-Dispersive Spectrometry in the Next-Generation Analytical Electron Microscope

Published online by Cambridge University Press:  22 January 2016

Nestor J. Zaluzec
Nestor J. Zaluzec*
Affiliation:
Argonne National Laboratory, Electron Microscopy Center, Center for Nanoscale Materials, Argonne, 60439 Illinois, USA
*
*Corresponding author. [email protected]
Get access

Abstract

Modern analytical electron microscopes equipped with silicon drift detectors now allow for a wide range of geometrical configurations capable of performing quantitative X-ray spectrometry. Recent work has improved the collection solid angles of these detectors, however, the impact of increasing the solid angle on detection sensitivity as measured by the peak/background ratio has not been addressed. This work compares theoretical and experimental peak/background ratios for incident electron energies in the range of 20–200 keV, with X-ray detectors in both conventional orientations (on the electron entrance surface) as well as new geometries (the electron exit surface). The implications of these parameters on detectability limits for the next generations of “Lab-in-the-Gap” analytical microscope are also considered. It was found that theoretical calculations of the angular distribution of bremsstrahlung and their effects on the peak/background ratio match well with experimental measurements, and indicate that new geometries which can result in large solid angles provided an added benefit in addition to increased characteristic signal, namely increased sensitivity for the analyst.

Keywords

X-ray microanalysisAEMpeak/backgroundMMF/MDMXEDS
Type
Techniques, Software, and Equipment
Information
Microscopy and Microanalysis , Volume 22 , Issue 1 , February 2016 , pp. 230 - 236
Copyright
© Microscopy Society of America 2016 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Allen, L.J., D’Alfonso, A.J. & Findlay, S.D. (2015). Modeling the inelastic scattering of fast electrons. Ultramicroscopy 151, 11–22.CrossRefGoogle ScholarPubMed
Cliff, G., Nasir, M.J., Lorimer, G.W. & Ridley, N. (1978). X-ray microanalysis of thin specimens in the transmission electron microscope at voltages up to 1000 kV, 9th International Congress on Electron Microscopy, Toronto-1978. Physics 1, 540–541.Google Scholar
Colliex, C. (2014). Seeing and measuring with electrons: Transmission electron microscopy today and tomorrow—an introduction). C R Phys 15, 101–109.CrossRefGoogle Scholar
D’Alfonso, A.J., Freitag, B., Klenov, D. & Allen, L.J. (2010). Atomic resolution chemical mapping using energy dispersive X-ray spectroscopy. Phys Rev B 81, 1001010R.CrossRefGoogle Scholar
Goldstein, J.I. (1979). Principles of thin film X-ray microanalysis. In Introduction to Analytical Electron Microscopy, Hren, Goldstein, Joy (Eds.), Chapter 3, pp. 83–120. New York: Plenum Press.CrossRefGoogle Scholar
Inokuti, M. (1971). Inelastic collision of fast charged particles with atoms and molecules—The Bethe theory revisited. Rev Mod Phys 43, 297–371.CrossRefGoogle Scholar
Inokuti, M. (1978). Electron-scattering cross sections pertinent to electron microscopy, AEM. In Proceedings of the Specialist Workshop 1978 AEM Workshop, Cornell University, pp. 220–231. The Cornell Center For Materials Research Records, 1970--2008 Collection Number: 53-24-3676, Division of Rare and Manuscript Collections Cornell University Library, Box 9, Folder 26. Available at http://rmc.library.cornell.edu/EAD/xml/dlxs/RMA03676.xml (retrieved January 2, 2016).Google Scholar
Joy, D.C. & Maher, D.M. (1977). Sensitivity limits for thin specimen X-ray analysis. Scanning Electron Microsc 5, 325.Google Scholar
Joy, D.C. & Maher, D.M. (1980). Electron energy loss spectroscopy: Detectable limits for elemental analysis. Ultramicroscopy 5, 333–342.CrossRefGoogle Scholar
Kirkpatrick, P. & Wiedmann, L. (1945). Theoretical continuous X-ray energy and polarization. Phys Rev 67(11), 321–339.CrossRefGoogle Scholar
Motz, J.W. & Placious, R.C. (1958). Bremsstrahlung cross-section measurements for 50-keV electrons. Phys Rev 109(2), 235–242.CrossRefGoogle Scholar
Scherzer, O. (1932). Uber die Ausstrahlund, bei der Bremsung von Protonen und Schnellen Electronen. Ann D Physik 13(2), 137–160.CrossRefGoogle Scholar
Smith, D.J. (2012). Progress and problems for atomic-resolution electron microscopy. Micron 43, 504–508.CrossRefGoogle Scholar
Sommerfeld, A. (1931). Uber die Beugung und Bremsung der Electronen. Ann D Phys 11(3), 256–330.Google Scholar
US DoE BES Electron Scattering Report (2007). Future science needs and opportunities for electron scattering: Next-generation instrumentation and beyond. Available at http://science.energy.gov/~/media/bes/pdf/reports/files/es_rpt.pdf (retrieved January 2, 2016)Google Scholar
US DoE BES Electron Scattering Report (2014). Future of electron gscattering and diffraction. Available at http://science.energy.ov/~/media/bes/pdf/reports/files/future_of_electron_scattering.pdf (retrieved January 2, 2016).Google Scholar
Zaluzec, N.J. (1978). Optimizing conditions for X-ray microchemical analysis in analytical electron microscopy, 9th International Congress on Electron Microscopy, Toronto-1978. Physics 1, 548–549.Google Scholar
Zaluzec, N.J. (1979). Quantitative X-ray microanalysis: Instrumental considerations and applications to materials science. In Introduction to Analytical Electron Microscopy, Chapter 4, pp. 121–168. New York: Plenum Press.CrossRefGoogle Scholar
Zaluzec, N.J. (1984). K and L cross-sections for X-ray microanalysis in an AEM. In Analytical Electron Microscopy—1984, Williams, D.B. & Joy, D.C. (Eds.), pp. 279–284. San Francisco, CA: San Francisco Press.Google Scholar
Zaluzec, N.J. (2014). Analytical formulae for calculation of X-ray detector solid angles in the scanning and scanning/transmission analytical electron microscope. Microsc Microanal 20, 1318–1326.CrossRefGoogle ScholarPubMed
Zaluzec, N.J. (2015). The influence of Cs/Cc correction in analytical imaging and spectroscopy in scanning and transmission electron microscopy. Ultramicroscopy 151, 240–249.CrossRefGoogle ScholarPubMed
Ziebold, T.O. (1967). Precision and sensitivity in electron microprobe analysis. Anal Chem 39, 858–861.CrossRefGoogle Scholar