Title :
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
fDate :
June 27 1994-July 1 1994
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;
Conference_Titel :
Precision Electromagnetic Measurements, 1994. Digest., 1994 Conference on
Conference_Location :
Boulder, CO, USA
Print_ISBN :
0-7803-1984-2
DOI :
10.1109/CPEM.1994.333192
