Hostname: page-component-8448b6f56d-cfpbc Total loading time: 0 Render date: 2024-04-24T04:46:53.663Z Has data issue: false hasContentIssue false
  • English
  • Français

Electron Channeling: A Problem for X-Ray Microanalysis in Materials Science

Published online by Cambridge University Press:  16 March 2009

Frederick Meisenkothen ,
Robert Wheeler ,
Michael D. Uchic ,
Robert D. Kerns  and
Frank J. Scheltens
Frederick Meisenkothen*
Affiliation:
Air Force Research Laboratory, Materials Characterization Facility, operated by UES, Inc., Wright Patterson Air Force Base, OH 45433, USA
Robert Wheeler
Affiliation:
Air Force Research Laboratory, Materials Characterization Facility, operated by UES, Inc., Wright Patterson Air Force Base, OH 45433, USA
Michael D. Uchic
Affiliation:
Air Force Research Laboratory, Materials and Manufacturing Directorate, Metals Development Group, Wright Patterson Air Force Base, OH 45433, USA
Robert D. Kerns
Affiliation:
Air Force Research Laboratory, Materials Characterization Facility, operated by UES, Inc., Wright Patterson Air Force Base, OH 45433, USA
Frank J. Scheltens
Affiliation:
Air Force Research Laboratory, Materials Characterization Facility, operated by UES, Inc., Wright Patterson Air Force Base, OH 45433, USA
*
Corresponding author. E-mail: frederick.meisenkothen@wpafb.af.mil
Get access

Abstract

Electron channeling effects can create measurable signal intensity variations in all product signals that result from the scattering of the electron beam within a crystalline specimen. Of particular interest to the X-ray microanalyst are any variations that occur within the characteristic X-ray signal that are not directly related to a specimen composition variation. Many studies have documented the effect of crystallographic orientation on the local X-ray yield; however, the vast majority of these studies were carried out on thin foil specimens examined in transmission. Only a few studies have addressed these effects in bulk specimen materials, and these analyses were generally carried out at common scanning electron microscope microanalysis overvoltages (>1.5). At these overvoltage levels, the anomalous transmission effect is weak. As a result, the effect of electron channeling on the characteristic X-ray signal intensity has traditionally been overlooked in the field of quantitative electron probe microanalysis. The present work will demonstrate that electron channeling can produce X-ray variations of up to 26%, between intensity maxima and minima, in low overvoltage X-ray microanalyses of bulk specimens. Intensity variations of this magnitude will significantly impact the accuracy of qualitative and quantitative X-ray microanalyses at low overvoltage on engineering structural materials.

Keywords

channelingEPMAelectron probe microanalysisX-ray microanalysisWDSEDSanomalous transmissionanomalous absorptionovervoltage
Type
Microanalysis
Information
Microscopy and Microanalysis , Volume 15 , Issue 2 , April 2009 , pp. 83 - 92
Copyright
Copyright © Microscopy Society of America 2009

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

REFERENCES

Booker, G.R., Shaw, A.M.B., Whelan, M.J. & Hirsch, P.B. (1967). Some comments on the interpretation of the “Kikuchi-like reflection patterns” observed by scanning electron microscopy. Phil Mag 16, 1185–1191.CrossRefGoogle Scholar
Borrmann, G. (1941). Uber Extinktionsdiagramme der Rontgenstrahlen von Quartz. Z Phys 42, 157–162.Google Scholar
Bramman, J.I. & Yates, G. (1969). Specimen surface preparation errors in quantitative electron-probe microanalysis. J Appl Crystallogr 2, 18–24.CrossRefGoogle Scholar
Campbell, H.N. (1951). X-ray absorption in a crystal set at the Bragg angle. J Appl Phys 22, 1139–1142.CrossRefGoogle Scholar
Cherns, D. & Howie, A. (1973). Characteristic X-ray production in thin films. Z Naturforsch A28, 565–571.CrossRefGoogle Scholar
Coates, D.G. (1967). Kikuchi-like reflection patterns obtained with the scanning electron microscope. Phil Mag 16, 1179–1184.CrossRefGoogle Scholar
Duncumb, P. (1962). Enhanced X-ray emission from extinction contours in a single-crystal gold film. Phil Mag 7, 2102–2105.CrossRefGoogle Scholar
Ewald, P.P. (1979). A review of my papers on crystal optics 1912 to 1968. Acta Crystallogr A35, 1–9.CrossRefGoogle Scholar
Goldstein, J.I., Newbury, D.E., Echlin, P., Joy, D.C., Romig, A.D., Lyman, C.E., Fiori, C. & Lifshin, E. (1992). Scanning Electron Microscopy and X-ray Microanalysis, p. 401. New York: Plenum Press.CrossRefGoogle Scholar
Hall, C.R. (1966). On the production of characteristic X-rays in thin metal crystals. ProcRoyal Society of London A 295, 140–163.Google Scholar
Hashimoto, H., Howie, A. & Whelan, M.J. (1962). Anomalous electron absorption effects in metal foils: Theory and comparison with experiment. Proc Royal Society 269, 80–103.Google Scholar
Hirsch, P.B. (1952). The reflexion and transmission of X-rays in perfect absorbing crystals. Acta Crystallogr 5, 176–181.CrossRefGoogle Scholar
Hirsch, P.B., Howie, A. & Whelan, M.J. (1962). On the production of X-rays in thin metal foils. Phil Mag 7, 2095–2100.CrossRefGoogle Scholar
Hirsch, P.B. & Humphreys, C.J. (1970). The dynamical theory of scanning electron microscope channelling patterns. In Scanning Electron Microscopy; Proceedings of the Third Annual Scanning Electron Microscope Symposium, pp. 451–455. Chicago: IIT Research Institute.Google Scholar
Howie, A. (1962). Inelastic scattering of electrons and anomalous absorption effects. In Proceedings from the Fifth International Congress for Electron Microscopy, p. AA-9. Philadelphia, New York: Academic Press.Google Scholar
Humphreys, C.J. (1979). The scattering of fast electrons by crystals. Rep Prog Phys 42, 11, 1825–1887.CrossRefGoogle Scholar
Joy, D.C. & Booker, G.R. (1974). U.S. Patent # 3786271.Google Scholar
Joy, D.C., Newbury, D.E. & Davidson, D.L. (1982). Electron channeling patterns in the scanning electron microscope. J Appl Phys 53, R81–R122.CrossRefGoogle Scholar
Miyake, S., Hayakawa, K. & Miida, R. (1968). Variation of emission yield of X-rays from crystals with diffraction condition of exciting electrons. Acta Crystallogr A24, 182–191.CrossRefGoogle Scholar
Morin, P., Pitaval, M., Besnard, D. & Fontaine, G. (1979). Electron channelling imaging in scanning electron microscopy. Phil Mag A 40, 511–524.CrossRefGoogle Scholar
Newbury, D.E., Joy, D.C., Echlin, P., Fiori, C.E. & Goldstein, J.I. (1986). Advanced Scanning Electron Microscopy and X-ray Microanalysis, pp. 87–142. New York: Plenum Press.CrossRefGoogle Scholar
Schulson, E.M. & van Essen, C.G. (1969). Optimum conditions for generating channelling patterns in the scanning electron microscope. J Sci Instrum (J Phys) 2, 247–251.CrossRefGoogle Scholar
Spencer, J.P. (1972). The crystallographic orientation dependence of X-ray production from bulk crystals: A theoretical assessment. In Electron Microscopy; Proceedings of the Fifth European Congress on Electron Microscopy, pp. 478–479. London: University of Manchester, The Institute of Physics.Google Scholar
von Laue, M. (1949). Die Absorption der Rontgenstrahlen in Kristallen im Interferenzfall. Acta Crystallogr 2, 106–113.CrossRefGoogle Scholar