Silicon lattice comparisons related to the Avogadro project: uniformity of new material and surface preparation effects

The lattice parameter of the28Si spheres in the determination of the Avogadro constant

“…It was doped with nitrogen to prevent precipitation of vacancies and self-interstitials; detailed information about the crystal characterization can be found in [8,11]. The homogeneity of its lattice parameter was investigated by the PTB and NIST [12,13]. Three X-ray interferometers were cut at 91 cm and 87 cm distances from the crystal seed.…”

A vacuum double-crystal spectrometer for reference-free X-ray spectroscopy of highly charged ions

“…Kessler et al (1994) The physical separation between the "delta-d " diffraction crystal and the DCS diffraction crystals was kept as small a possible so that any variation in lattice spacing along the boule will have negligible influence on the determination of the lattice spacing of the DCS diffraction crystals. Although it is expected that the lattice spacings of the two samples are identical, a relative uncertainty component of 10 −8 is included in the lattice spacing uncertainty to account for possible sample-to-sample variations Kessler et al (1999). The "delta-d " crystal was cut from a 18 mm×12 mm×6 mm sample with a thin lamella for diffraction as the top half and a base for mounting as the bottom half.…”

“…An other sample crystal, the reference crystal, cut from the WASO04 silicon boule, was also mounted on the translation sled. The WASO04 boule, also grown by Wacker-Siltronic, is a nearly perfect single crystal natural silicon material that was specifically grown for the International Avogadro Project Andreas et al (2011); Fujii et al (2005); Kessler et al (1994Kessler et al ( , 1999; Massa et al (2011); Mohr et al (2008). The lattice spacing of the WASO04/NIST reference crystal was determined as part of the International Avogadro Project Massa et al (2011).…”