[Sphères de silicium pour la future réalisation des définitions du kilogramme et de la mole]
De nouvelles définitions des unités de quantité de matière (la mole) et de masse (le kilogramme) entreront vraisemblablement en vigueur lors de la Journée mondiale de la métrologie de 2019. Dans le Système international révisé, la mole sera définie par une valeur fixe de la constante d'Avogadro et le kilogramme par une valeur fixe de la constante de Planck. La méthode de mesure de densité par cristallographie aux rayons X (XRCD – X-ray crystal density) a été utilisée pour déterminer ces constantes fondamentales par comptage du nombre d'atomes dans des sphères de silicium enrichi en silicium 28. Après la redéfinition, les définitions de la mole et du kilogramme seront ainsi réalisées à l'aide de sphères de silicium. Ceci est possible en effectuant des mesures des paramètres de réseau, de la composition isotopique, du volume et des propriétés de surface traçables au SI. On obtient alors une incertitude-type relative inférieure à . Alors qu'une telle précision ne peut être atteinte qu'avec du silicium enrichi isotopiquement, il est également prévu d'utiliser des sphères de silicium naturel avec un niveau de précision légèrement inférieur. Les futures définitions permettront également de mettre en oeuvre de nouvelles méthodes de réalisation faisant appel au silicium, en particulier pour de faibles valeurs de masses.
New definitions of the units for amount of substance – the mole – and for mass – the kilogram – will presumably come into force on the World Metrology Day 2019. In the revised SI, the mole will be defined by a fixed value of the Avogadro constant and the kilogram by a fixed value of the Planck constant. The X-ray-crystal-density (XRCD) method has been used for the determination of these fundamental constants by counting the number of atoms in 28Si-enriched spheres. Thus, silicon spheres will – after the redefinition – be used to realize the definitions of the mole and the kilogram. This is possible by SI-traceable measurements of lattice parameter, isotopic composition, volume, and surface properties, yielding a relative standard uncertainty below 2⋅10−8. Whereas this high accuracy is only reached with isotopically enriched silicon, it is also planned to use natural silicon spheres on a slightly lower level of accuracy. The future definitions will allow also new realization methods using silicon, in particular for small mass values.
Mot clés : Méthode XRCD, Silicium, Sphères, SI révisé, Constante de Planck, Constante d'Avogadro
Horst Bettin 1 ; Kenichi Fujii 2 ; Arnold Nicolaus 1
@article{CRPHYS_2019__20_1-2_64_0, author = {Horst Bettin and Kenichi Fujii and Arnold Nicolaus}, title = {Silicon spheres for the future realization of the kilogram and the mole}, journal = {Comptes Rendus. Physique}, pages = {64--76}, publisher = {Elsevier}, volume = {20}, number = {1-2}, year = {2019}, doi = {10.1016/j.crhy.2018.12.005}, language = {en}, }
TY - JOUR AU - Horst Bettin AU - Kenichi Fujii AU - Arnold Nicolaus TI - Silicon spheres for the future realization of the kilogram and the mole JO - Comptes Rendus. Physique PY - 2019 SP - 64 EP - 76 VL - 20 IS - 1-2 PB - Elsevier DO - 10.1016/j.crhy.2018.12.005 LA - en ID - CRPHYS_2019__20_1-2_64_0 ER -
Horst Bettin; Kenichi Fujii; Arnold Nicolaus. Silicon spheres for the future realization of the kilogram and the mole. Comptes Rendus. Physique, Volume 20 (2019) no. 1-2, pp. 64-76. doi : 10.1016/j.crhy.2018.12.005. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2018.12.005/
[1] The Avogadro constant for the definition and realization of the mole, Ann. Phys. (2018) (1800292, pp. 1–17)
[2] The watt or Kibble balance: a technique for implementing the new SI definition of the unit of mass, Metrologia, Volume 53 (2016), p. A46-A74
[3] Realization of the kilogram by the XRCD method, Metrologia, Volume 53 (2016), p. A19-A45
[4] An X-ray interferometer, Appl. Phys. Lett., Volume 6 (1965), pp. 155-156
[5] Polishing a 1-kg silicon sphere for a density standard, Appl. Opt., Volume 26 (1987), pp. 600-601
[6] et al. Large-scale production of highly enriched 28Si for the precise determination of the Avogadro constant, Meas. Sci. Technol., Volume 17 (2006), pp. 1854-1860
[7] Novel concept for the mass spectrometric determination of absolute isotopic abundances with improved measurement uncertainty: part 1 – theoretical derivation and feasibility study, Int. J. Mass Spectrom., Volume 289 (2010), pp. 47-53
[8] Avogadro constant measurements using enriched 28Si monocrystals, Metrologia, Volume 55 (2018), p. L1-L4
[9] The CODATA 2017 values of h, e, k, and for the revision of the SI, Metrologia, Volume 55 (2018), p. L13-L16
[10] Data and analysis for the CODATA 2017 special fundamental constants adjustment, Metrologia, Volume 55 (2018), pp. 125-146
[11] Precise determination of the ratio h/: a way to link microscopic mass to the new kilogram, Metrologia, Volume 53 (2016), p. A75-A82
[12] CODATA recommended values of the fundamental physical constants: 2014, Rev. Mod. Phys., Volume 88 (2016) (pp. 1–73)
[13] Measurement of the fine-structure constant as a test of the Standard Model, Science, Volume 360 (2018), pp. 191-195
[14] et al. A new 28Si single crystal: counting the atoms for the new kilogram definition, Metrologia, Volume 54 (2017), pp. 693-715
[15] Diameter comparison of a silicon sphere for the international Avogadro coordination project, IEEE Trans. Instrum. Meas., Volume 60 (2011), pp. 2615-2620
[16] Primary calibration of the volume of silicon spheres, Meas. Sci. Technol., Volume 17 (2006), pp. 2527-2539
[17] Volume measurement of 28Si spheres using an interferometer with a flat etalon to determine the Avogadro constant, Metrologia, Volume 48 (2011), p. S83-S95
[18] Volume determination of the Avogadro spheres of highly enriched 28Si with a spherical Fizeau interferometer, Metrologia, Volume 48 (2011), p. S96-S103
[19] Volume determination of fused quartz spheres, Metrologia, Volume 27 (1990), pp. 25-31
[20] The international temperature scale of 1990 (ITS-90), Metrologia, Volume 27 (1990), pp. 3-10
[21] The coefficient of thermal expansion of highly enriched 28Si, Metrologia, Volume 46 (2009), pp. 416-422
[22] et al. Counting the atoms in a 28Si crystal for a new kilogram definition, Metrologia, Volume 48 (2011), p. S1-S13
[23] et al. A new generation of 99.999% enriched 28Si single crystals for the determination of Avogadro's constant, Metrologia, Volume 54 (2017), pp. 599-609
[24] et al. Large-scale production of highly enriched 28Si for the precise determination of the Avogadro constant, Meas. Sci. Technol., Volume 17 (2006), pp. 1854-1860
[25] Surface layer determination for the Si spheres of the Avogadro project, Metrologia, Volume 48 (2011), p. S62-S82
[26] et al. Critical review of the current status of thickness measurements for ultra thin SiO2 on Si – part v: results of a CCQM pilot study, Surf. Interface Anal., Volume 36 (2004), pp. 1269-1303
[27] Thickness measurements of oxide and carbonaceous layer on a 28Si sphere by XPS, IEEE Trans. Instrum. Meas., Volume 66 (2017), pp. 1297-1303
[28] Quantitative surface characterization of silicon spheres by combined XRF and XPS analysis for the determination of the Avogadro constant, Metrologia, Volume 54 (2017), pp. 653-662
[29] Determination of the amount of gas adsorption on SiO2/Si(100) surfaces to realize precise mass measurement, Metrologia, Volume 41 (2004), pp. 137-144
[30] Infrared spectrometric measurements of impurities in highly enriched ‘Si28’, Metrologia, Volume 48 (2011), p. S14-S19
[31] Purity of 28Si-enriched silicon material used for the determination of the Avogadro constant, Anal. Chem., Volume 88 (2016), pp. 6881-6888
[32] Intrinsic point defects in silicon crystal growth, Solid State Phenom., Volume 178–179 (2011), pp. 3-14
[33] Air-vacuum transfer; establishing traceability to the new kilogram, Metrologia, Volume 53 (2016), p. A95-A113
[34] et al. Improved measurement results for the Avogadro constant using a 28Si-enriched crystal, Metrologia, Volume 52 (2015), pp. 360-375
[35] The lattice parameter of the 28Si spheres in the determination of the Avogadro constant, Metrologia, Volume 48 (2011), p. S44-S49
[36] Uniformity evaluation of lattice spacing of 28Si single crystals, IEEE Trans. Instrum. Meas., Volume 66 (2017), pp. 1304-1308
[37] Development of a specialized hydrostatic comparator for the accurate density determination of natural silicon spheres: a novel method for a primary realization of the unit kilogram, Paris, France, 8–13 July, Digest (2018), pp. 627-628
Cité par Sources :
Commentaires - Politique