A new method to measure silicon lattice spacings and possible new definition of the kilogram: scheme and progress

For possible new definition of the kilogram, we propose to use picometer metrology and AFM to continuously scan with atomic resolution a surface strip of about 2 nm/spl times/10 mm area on a single silicon crystal in a 2/spl times/10/sup -11/ torr vacuum chamber to measure silicon lattice spacings to 0.1-1 ppb. >