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Calibration of the monochromator bandpass function for the X-ray Rietveld analysis

Published online by Cambridge University Press:  10 January 2013

P. Riello ,
P. Canton  and
G. Fagherazzi
P. Riello
Affiliation:
Dipartimento di Chimica Fisica, Università di Venezia, DD2137, 30123 Venezia, Italy
P. Canton
Affiliation:
Dipartimento di Chimica Fisica, Università di Venezia, DD2137, 30123 Venezia, Italy
G. Fagherazzi
Affiliation:
Dipartimento di Chimica Fisica, Università di Venezia, DD2137, 30123 Venezia, Italy
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Abstract

In this paper we propose a fitting procedure to describe the bandpass effect on all x radiation that passes through a focusing graphite monochromator used on the diffracted beam. The proposed bandpass function is: M(2θ)=1/(1+Kmon1sKmon2), with s=(2 sin θ)/λ, where Kmon1 and Kmon2 are constants which have been refined by means of a Rietveld analysis, using a physically modeled background (Riello et al., J. Appl. Crystallogr. 28, 115–120). We have investigated two polycrystalline powders: α-Al2O3 and a mixture of α and β-Si3N4. The so-obtained bandpass functions for these materials are close enough to conclude that they depend only on the used experimental setup (in the present case the X-Pert-Philips diffractometer with a graphite focusing monochromator). Knowledge of the bandpass function is important to suitably model the Compton scattering, which is a component of the background scattering. The present procedure allows one to avoid the direct experimental determination of the bandpass function, which requires the use of another monochromator (analyzer) and another tube with an intense white spectrum.

Type
Research Article
Information
Powder Diffraction , Volume 12 , Issue 3 , September 1997 , pp. 160 - 166
Copyright
Copyright © Cambridge University Press 1997

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References

Benedetti, A., Bottarelli, M., and Fagherazzi, G. (1985). “Crystallinity determination of partially crystallized glasses of the systems SiO 2-Li 2O-ZnO and SiO 2-Li 2O-TiO 2-Al 2O 3: A comparison of different methods,” J. Non-Cryst. Solids 74, 245–257.Google Scholar
Bish, D. L., and Howard, S. A. (1988). “Quantitative phase analysis using the Rietveld method,” J. Appl. Crystallogr. 21, 86–91.CrossRefGoogle Scholar
Grün, R. (1979). “The crystal structure of β-Si 3N 4: Structural and stability considerations between α- and β-Si 3N 4,” Acta Crystallogr., Sec. B 35, 800–804.CrossRefGoogle Scholar
Hill, R. J., and Madsen, I. C. (1986). “The effect of profile step width on the determination of crystal structure parameters and estimated standard deviations by X-ray Rietveld analysis,” J. Appl. Crystallogr. 19, 10–18.CrossRefGoogle Scholar
Kato, K., Inoue, Z., Kijima, K., Kawada, I., Tanaka, H., and Yamane, T. (1975). “Structural approach to the problem of oxygen content in alpha silicon nitride,” J. Am. Ceram. Soc. 58, 90–91.CrossRefGoogle Scholar
Lewis, J., Schwarzenbach, D., and Flack, H. D. (1982). “Electric field gradients and charge density in corundum, α-Al 2O 3,” Acta Crystallogr. Sec. A 38, 733–739.CrossRefGoogle Scholar
Marchand, R., Laurent, Y., and Lang, J. (1969). “Structure du nitrure de silicium α,” Acta Crystallogr. Sec. B 25, 2157–2160.CrossRefGoogle Scholar
Polizzi, S., Fagherazzi, G., Benedetti, A., Battagliarin, M., and Asano, T. (1990). “A fitting method for the determination of crystallinity by means of X-ray diffraction,” J. Appl. Crystallogr. 23, 359–365.Google Scholar
Riello, P., Canton, P., and Fagherazzi, G. (1995a). “A semi-empirical asymmetry function for X-ray diffraction peak profiles,” Powder Diffr. 10, 204–206.Google Scholar
Riello, P., Fagherazzi, G., Canton, P., Clemente, D., and Signoretto, M. (1995c). “Determining the degree of crystallinity in semicrystalline materials by means of the Rietveld analysis,” J. Appl. Crystallogr. 28, 121–126.CrossRefGoogle Scholar
Riello, P., Fagherazzi, G., Clemente, D., and Canton, P. (1995b). “X-ray Rietveld analysis with a physically based background,” J. Appl. Crystallogr. 28, 115–120.Google Scholar
Ruland, W. (1961). “X-ray determination of crystallinity and diffuse disorder scattering,” Acta Crystallogr. 14, 1180–1185.CrossRefGoogle Scholar
Ruland, W. (1964). “The separation of coherent and incoherent compton X-ray scattering,” Br. J. Appl. Phys. 15, 1301–1307.Google Scholar
Schneider, J., Frey, N., Johnson, N., and Lashke, K. (1994). “Structure refinements of β-Si 3N 4 at temperatures up to 1360 °C by X-ray powder investigation,” Z. Kristallogr. 209, 328–333.Google Scholar
Yang, P., Fun, H. K., Rahman, I. A., and Saleh, M. I. (1995). “Two phase refinements of the structures of α-Si 3N 4 and β-Si 3N 4 made from rice husk by Rietveld analysis,” Ceram. Intern. 21, 137–142.Google Scholar
Young, R. A. (1993). “Introduction to the Rietveld method,” in The Rietveld Method, edited by R. A. Young (IUCR, Oxford University Press, Oxford).Google Scholar