Homogeneity characterization of lattice spacing of 28Si single crystals

The homogeneity of the lattice spacing of silicon single crystals was characterized by the self-referenced lattice comparator. Lattice strain measurements were performed on single crystals from ²⁸Si ingot (Avo28), which was used to determine the Avogadro constant. A curved and layered pattern was observed for the sample of 10.5 cut from the tail-side of the Avo28 ingot. The homogeneity of the lattice constant of the Avo28 was discussed.