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Abstract

Modern determinations of the Avogadro constant are based on the parameter M(Si), the molar mass of silicon in a Si single crystal. A long-term project at CBNM Geel aimed to reduce the uncertainties on M(Si) in order to improve the uncertainty of the Avogadro constant by a factor of 10. The measurement method and the preparation of samples are described, and the principles governing the preparation of the synthetic Si isotope mixtures are outlined. The Cs(2)SiF(6) compound was used because it fulfilled all the required conditions (chemical purity, stoichiometry and weighability) for the chemical compound carrying the isotope mixtures. The value of Avogadro's constant was determined as 6.022 136 3 x 1.0 E23/mol with an uncertainty of 1.1 x 1.0 E-6.

Additional information

Authors: DE BIEVRE P, JRC Geel (BE);VALKIERS S, JRC Geel (BE);SCHAEFER F, JRC Geel (BE)
Bibliographic Reference: Paper presented: 9th International Conference on Atomic Masses and Fundamental Constants, Bernkastel-Kues (DE), July 19-24, 1992
Availability: Available from (1) as Paper EN 37001 ORA
Record Number: 199210988 / Last updated on: 1994-12-02
Category: PUBLICATION
Original language: en
Available languages: en