UNCERTAINTY ESTIMATION OF LATTICE PARAMETERS MEASURED BY X-RAY DIFFRACTION

Marcos F. de Campos, Jailton C. Damasceno, Rogério Machado, Carlos A. Achete
Abstract:
Abstract: The uncertainties in lattice parameters determination, for X-Ray Diffractometers with Bragg- Brentano geometry, were estimated according GUM recommendations using the Monte Carlo simulation approach. The analyzed specimen was a Corundum NIST 1976 SRM Standard. Misalignment of instrument (zero 2theta offset and peak position) is an important error source, and should be kept (2θ) < 0.015° to be able to perform lattice parameters measurements with an accuracy = 0.0001 Angstrons. Sample displacement is in general the main source of error, and the above mentioned misalignment of instrument (0.015°) only becomes dominant as error source if the sample displacement is very small (<10 µm). The analysis showed that sample absorption (Corundum) is negligible as error source, if compared with sample displacement and equipment misalignment. Other possible sources of systematic error are discussed.
Keywords:
lattice parameters, X-Ray diffraction, error estimative, GUM, diffractometers
Download:
PWC-2006-TC8-008u.pdf
DOI:
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Event details
Event name:
XVIII IMEKO World Congress
Title:

Metrology for a Sustainable Development

Place:
Rio de Janeiro, BRAZIL
Time:
17 September 2006 - 22 September 2006