Density measurements of silicon crystals by hydrostatic weighing [for Avogadro constant determination]

Author

Fujii, Kenichi ; Waseda, Atsushi ; Tanaka, Mitsuru

Author_Institution

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

Volume

50

Issue

2

fYear

2001

fDate

4/1/2001 12:00:00 AM

Firstpage

616

Lastpage

621

Abstract

Through research for a determination of the Avogadro constant by the X-ray crystal density method, a primary density standard based on silicon crystals was established at the NRLM with a relative combined standard uncertainty of 1.0×10^-7. To investigate the cause of the existing discrepancy in the molar volume of silicon in single crystals, a new hydrostatic weighing system has been developed for evaluating the consistency in the absolute density values of the silicon crystals used for the determination of the Avogadro constant. This system measures the density of a solid material under study with respect to that of a primary standard with a relative combined standard uncertainty of 1.3×10^-7. Some measurement results on silicon spheres fabricated from different silicon ingots are described

Keywords

constants; density measurement; measurement standards; measurement uncertainty; silicon; weighing; Avogadro constant determination; Si; X-ray crystal density method; absolute density values; automated system; density measurements; hydrostatic weighing; molar volume discrepancy; primary density standard; relative combined standard uncertainty; silicon single crystals; silicon spheres; Crystalline materials; Crystals; Density measurement; Laboratories; Measurement standards; Metrology; Optical interferometry; Silicon; Solids; Volume measurement;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/19.918205

Filename

918205