A Silicon d-spacing Mapping Measurement System With Resolution of 10-9.

For determination of the Avogadro’s number, a self-referenced lattice comparator established at the Photon Factory to deal with a d-spacing mapping measurement over the cross section of a 4 ∼ 5 inches FZ silicon rod. For uncertainty of 1×10^-8 of the unit cell volume, it is necessary to measure lattice parameter of silicon with resolution of 3×10^-9 at least. In this paper, we report the principle of our lattice comparator, characterize our measurement system, and show some mapping measurement results of FZ silicon with resolution of 3×10^-9. [ABSTRACT FROM AUTHOR]