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The Si-Route to the Avogadro Constant: Latest Measurements on Natural Silicon; Highly Enriched 28Si Is Next



P De Bievre, S Valkiers, P D. Taylor, P Becker, H Bettin, U Kuetgens, A Nicolaus, H U. Danzebrink, K Fujii, A Waseda, Giovanni Mana, A Peuto, M J. Kenny, A J. Leistner, R Kessel, G Zosi, A Picard, F Spaepen, H Riemann, H S. Peiser


New measurements of the molar volume and lattice parameter of natSi, in near-perfect Si crystals, are reported. The present determination confirms the previously published value of the Avogadro constant within the stated uncertainty. all relevant information has been brought together in a Web-based database. Further reduction in uncertainty using natSi is unlikely. Future work will use 99.99 % enriched 28Si. All the measuremtnes are planned and performed within a worldwide, structured collaboration coordinated in the framework of the Working Group on the Avogadro constant of the CIPM-Consultative Committee on Mass and Related Quantities. The goal of this work is to contribute to the redefinition of the kilogram as SI unit for mass. A present best value for the molar volume of Si is released as 12,058 828 4 (18) cm3 and for the Avogadro constant as 6,022 137 7 (12) . 1023 mol-1.
Conference on Precision Electromagnetic Measurements


Avogadro constant, International System of Units, kilogram, natural silicon, Si, SI unit


De bievre, P. , Valkiers, S. , Taylor, P. , Becker, P. , Bettin, H. , Kuetgens, U. , Nicolaus, A. , Danzebrink, H. , Fujii, K. , Waseda, A. , Mana, G. , Peuto, A. , Kenny, M. , Leistner, A. , Kessel, R. , Zosi, G. , Picard, A. , Spaepen, F. , Riemann, H. and Peiser, H. (2008), The Si-Route to the Avogadro Constant: Latest Measurements on Natural Silicon; Highly Enriched <sup>28</sup>Si Is Next, Conference on Precision Electromagnetic Measurements (Accessed June 20, 2024)


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Created October 16, 2008