Absolute measurements of the densities of silicon crystals in vacuum for a determination of the Avogadro constant

Conference · Sat Dec 31 00:00:00 EST 1994

OSTI ID:125893

Fujii, K; Tanaka, M; Nezu, Y ^[1]

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1. National Research Lab. of Metrology, Ibaraki (Japan); and others

Absolute measurements of the densities of 1-kg single-crystal silicon spheres have been performed for a determination of the Avogadro constant. A scanning type optical interferometer was used to measure the diameters of the spheres in vacuum, and the volumes were obtained by fitting the diameters to a series of spherical harmonics. Thickness of oxide layers on the surfaces of the spheres has been determined by using an ellipsometer to evaluate the effect on the density. Total uncertainties of the densities are estimated to be 0.1 ppm.

• OSTI ID: 125893
• Report Number(s): CONF-940603-; TRN: 95:005769-0285
• Resource Relation: Conference: CPEM `94: conference on precision electromagnetic measurements, Boulder, CO (United States), 27 Jun - 1 Jul 1994; Other Information: PBD: 1994; Related Information: Is Part Of 1994 Conference on precision electromagnetic measurements digest; DeWeese, E.; Bennett, G. [eds.]; PB: 577 p.
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES
GASES
DIELECTRIC PROPERTIES
FUNDAMENTAL CONSTANTS
MEASURING METHODS