Accurate determination of the density of a crystal silicon sphere

Author

Fujii, Ken-ichi ; Tanaka, Mitsuru ; Nezu, Yoshiaki ; Nakayama, Kan ; Masui, Ryohei

Author_Institution

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

Volume

42

Issue

2

fYear

1993

fDate

4/1/1993 12:00:00 AM

Firstpage

395

Lastpage

400

Abstract

For an independent determination of the Avogadro constant, the density of a 1-kg crystal silicon sphere was determined by direct measurements of its mass and volume. A scanning-type interferometer was used to measure the diameters, and the volume was calculated from the mean of uniformly distributed diameters. The sphere was weighted using a balance for the prototype kilogram at the National Research Laboratory of Metrology (NRLM), and the mass was determined accurately by direct measurements of the buoyancy force acting on the sphere. The total uncertainty of the density is estimated to be 0.34 ppm. Effects of a thin oxide layer and impurities on the density of a pure crystal are evaluated

Keywords

constants; density measurement; elemental semiconductors; light interferometry; silicon; Avogadro constant; National Research Laboratory of Metrology; Si sphere; balance; buoyancy force; density measurement; diameters; impurities; prototype kilogram; pure crystal; scanning-type interferometer; thin oxide layer; uncertainty; volume; Density measurement; Force measurement; Mechanical variables measurement; Metrology; NIST; Optical interferometry; Prototypes; Silicon; Steel; Volume measurement;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/19.278589

Filename

278589