The lattice parameter of the<sup>28</sup>Si spheres in the determination of the Avogadro constant

Massa, Enrico; Mana, Giovanni; Ferroglio, Luca; Kessler, E. G.; Schiel, Detlef; Zakel, Sabine

doi:10.1088/0026-1394/48/2/s07

Cited by 30 publications

(29 citation statements)

References 20 publications

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“…NW04 d220 = 192.015 569 6(10) × 10 −12 m at 22.5 °C and 0 Pa [4]. In this paper, all of the lattice parameter values determined for previously unknown samples are traceable to the particular NW04 d220 lattice comparator standard or the W04 boule.…”

Section: Standard Crystalsmentioning

confidence: 86%

“…W04 d220 = 192.015 570 2(10) × 10 −12 m at 22.5 °C and 0 Pa (vacuum) [4,32,33]. The X-ray/optical interferometer measurements were performed near 22.5 °C and at 0 Pa. Corrections to account for small deviation from 22.5 °C are described later in this section.…”

Section: Standard Crystalsmentioning

confidence: 99%

“…Through the last 25 years, this instrument has been operational in four different locations at the NIST Gaithersburg, MD laboratory (two locations in the basement of Building 221, the Advanced Measurement Laboratory [AML], and the first floor of Building 223) and the responsibility of two NIST laboratories (Physical Measurement Laboratory [PML] and Materials Measurement Laboratory [MML]). From 1998 to 2011, the NIST lattice comparator played an important role in the International Avogadro Project by measuring lattice parameter variations in highly perfect isotopically natural silicon material and highly enriched 28 Si material [2][3][4]. More recently, the scope of ray path is sensed.…”

Section: Introductionmentioning

confidence: 99%

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The Lattice Spacing Variability of Intrinsic Float-Zone Silicon

Kessler¹,

Szabo²,

Cline³

et al. 2017

J. RES. NATL. INST. STAN.

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Precision lattice spacing comparison measurements at the National Institute of Standards and Technology (NIST) provide traceability of X-ray wavelength and powder diffraction standards to the international system of units (SI). Here, we both summarize and document key measurements from the last two decades on six lots of intrinsic float-zone silicon, including unpublished results and recent internal-consistency checks. The comparison measurements link the unknown lattice spacing of a test crystal to a standard crystal for which the lattice spacing has been accurately determined by X-ray/optical interferometry in units traceable to the definition of the meter. The crystal that serves as the standard in all the comparisons is WASO 04, for which the lattice spacing is known with a relative uncertainty of 5 × 10 ; taking material variability into account, measurements yield relative uncertainties for the test materials of a few tens of nanometers. It is observed that in the case of nearly perfect modern intrinsic float-zone silicon, the variability of the lattice spacing is sufficiently small that for most diffraction applications, a recommended reference value may be used.

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Section: Standard Crystalsmentioning

confidence: 86%

Section: Standard Crystalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Lattice Spacing Variability of Intrinsic Float-Zone Silicon

Kessler¹,

Szabo²,

Cline³

et al. 2017

J. RES. NATL. INST. STAN.

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“…Measurements were carried out at the TRIGA Mark II reactor at the University of Pavia and the OPAL reactor of the Australian Nuclear Science and Technology Organisation; they included 59 elements and excluded contaminations higher than 1 ng g −1 for 35 elements. Therefore, the lattice parameters of AVO28-S5 and AVO28-S8 spheres were obtained by extrapolation of the interferometer value accounting for the difference of carbon (C), oxygen (O), boron (B), and nitrogen (N) concentrations [42], which PTB surveyed by infrared spectroscopy [32].…”

Section: Lattice Parameter Measurementmentioning

confidence: 99%

Realization of the kilogram by the XRCD method

Fujii¹,

et al. 2016

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When the kilogram is redefined in terms of the fixed numerical value of the Planck constant h, the x-ray-crystal-density (XRCD) method, among others, is used for realizing the redefined kilogram. The XRCD method has been used for the determination of the Avogadro constant N A by counting the number of atoms in a 28 Si-enriched crystal, contributing to a substantial reduction of uncertainty in the values of N A and h to 2 parts in 10 8 . This method can be therefore used reversely for the mass determination of a 1 kg sphere prepared from the crystal. This is realized by SI-traceable measurements of its lattice parameter, isotopic composition, volume, and surface properties. Details of the corresponding measurements are provided, as well as the concept of the XRCD method, isotope enrichment, crystal production, sphere manufacturing, and evaluation of impurities and self-point defects in the crystal, together with mass comparison with respect to the silicon sphere for disseminating mass standards.

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“…Fortunately, in a 2011 publication a d 220 value for the specific WASO04/NIST reference crystal was determined Massa et al (2011). The lattice parameter of a sample taken from a specific location (87 cm from crystal seed) in the WASO04 boule was carefully measured.…”

Section: Absolute Lattice Parameter Valuementioning

confidence: 99%

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

Amaro

Szabo²,

Schlesser³

et al. 2014

Radiation Physics and Chemistry

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We have built a vacuum double crystal spectrometer, which coupled to an electron-cyclotron resonance ion source, allows to measure low-energy x-ray transitions in highly-charged ions with accuracies of the order of a few parts per million. We describe in detail the instrument and its performances. Furthermore, we present a few spectra of transitions in Ar 14+ , Ar 15+ and Ar 16+ . We have developed an ab initio simulation code that allows us to obtain accurate line profiles. It can reproduce experimental spectra with unprecedented accuracy. The quality of the profiles allows the direct determination of line width.

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

Cited by 30 publications

References 20 publications

The Lattice Spacing Variability of Intrinsic Float-Zone Silicon

The Lattice Spacing Variability of Intrinsic Float-Zone Silicon

Realization of the kilogram by the XRCD method

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

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

Cited by 30 publications

References 20 publications

The Lattice Spacing Variability of Intrinsic Float-Zone Silicon

The Lattice Spacing Variability of Intrinsic Float-Zone Silicon

Realization of the kilogram by the XRCD method

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

Contact Info

Product

Resources

About

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