X-ray crystal density study on a FZ silicon crystal for the determination of the Avogadro constant
Absolute measurements of the density, lattice spacing and molar mass, of samples from a FZ silicon ingot of highly perfect and pure crystal, give the Avogadro constant with an uncertainty of around 0.53 ppm. The nominal value of the Avogadro constant differs by 3 ppm from values reported previously. Spectroscopic ellipsometry analyzes the contribution of silica layers on the sphere to error in mass measurement, indicating a 0.3 ppm correction in the density. Analysis of the presence of macroscopic and microscopic defects ar made using X-ray computer tomography, broadening spectrum analysis in a position annihilation experiment, interferometric infrared microscopy and flow pattern study. None of these can explain the discrepancy, implying the necessity for further analysis.
Bibliographic Reference: Paper presented : CPEM '96, Braunschweig (DE), June 1996
Availability: Available from (1) as Paper EN 39926 ORA
Record Number: 199610931 / Last updated on: 1996-09-16
Original language: en
Available languages: en