Diameter determination of Avogadro sphere #1 and #2

Author

Nicolaus, R.A.

Author_Institution

Phys.-Technische Bundesanstalt, Braunschweig

fYear

2004

fDate

38139

Firstpage

447

Lastpage

448

Abstract

In the scope of the new determination of Avogadro´s constant, NA, the spheres interferometer of PTB was developed to measure the volume of the Avogadro sphere. The interferometer is based on spherical reference plates and spherical beams of rays. This allows not only one diameter in the center to be measured, but a big amount of diameter measurements available in a 60deg field of view. With all orientations of this 60deg cone a sphere is characterized by 500 000 diameter values. Avogadro sphere #1 of PTB and Avogadro sphere #2 of IMGC have been measured in 40 different orientations, so that fundamental knowledge of the spheres can be given. The additional information of surface topography leads to better understanding of uncertainty

Keywords

constants; diameter measurement; light interferometry; measurement uncertainty; surface topography; volume measurement; Avogadro sphere; Avogadro sphere volume; Avogadro´s constant; diameter measurements; interferometer; spherical beams; spherical reference plates; surface topography; uncertainty; Area measurement; Collimators; Interference; Lattices; Length measurement; Lenses; Position measurement; Silicon; Surface topography; Volume measurement;

fLanguage

English

Publisher

ieee

Conference_Titel

Precision Electromagnetic Measurements Digest, 2004 Conference on

Conference_Location

London

Print_ISBN

0-7803-8494-6

Electronic_ISBN

0-7803-8494-6

Type

conf

DOI

10.1109/CPEM.2004.305303

Filename

4097314