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

Author

Fujii, K. ; Tanaka, M. ; Nezu, Y. ; Sakuma, A. ; Leistner, A. ; Giardini, W.

Author_Institution

Nat. Res. Lab. of Metrol., Ibaraki, Japan

fYear

1994

fDate

June 27 1994-July 1 1994

Firstpage

508

Lastpage

509

Abstract

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.<>

Keywords

constants; diameter measurement; elemental semiconductors; ellipsometry; lattice constants; light interferometry; mass measurement; silicon; vacuum techniques; 1 kg; Avogadro constant; Si; Si crystals; absolute measurement; diameter measurement; ellipsometer; mass measurement; scanning type optical interferometer; spheres; spherical harmonics; thickness; uncertainties; volumes; Crystals; Density measurement; Laboratories; Laser beams; Metrology; Optical interferometry; Optical refraction; Optical variables control; Performance evaluation; Silicon;

fLanguage

English

Publisher

ieee

Conference_Titel

Precision Electromagnetic Measurements, 1994. Digest., 1994 Conference on

Conference_Location

Boulder, CO, USA

Print_ISBN

0-7803-1984-2

Type

conf

DOI

10.1109/CPEM.1994.333192

Filename

333192