Since the establishment of the revised SI the unit of mass, the kilogram, can be realized by two primary methods based on Planck's constant - the “Kibble balances” and the “XRCD” method (X-ray crystal density). The XRCD method is based on a high-quality characterization of spheres made of isotopically enriched 28Si silicon, which can be divided into two main activities, the determination of crystal/ material parameters and the determination of the macroscopic volume of 28Si spheres and their surface layers. This subdivision is of particular interest since the material parameters are considered constant and are not re-determined when the realization is “reactivated”. Before and after the redefinition of the kilogram, comparisons of the most accurate realization experiments were carried out. This publication discusses the parameters, methodology and instrumentation used by PTB for the participation in CCM.R kg P1 (Pilot Study) before redefinition in comparison to the results of the experiments for the participation in CCM.M K8.2019 and CCM.M K8.2021 after redefinition.
Grundlagen der Metrologie
; Metrologie für die Wirtschaft
Zitierung
Eppers, D., Knopf, D., Nicolaus, A., Kuhn, E., Borys, M., Müller, M., & Bettin, H. (2025). Status of the kilogram realisation using the XRCD method at PTB. Measurement: Sensors, 38(Suppl.), e1–e5. https://doi.org/10.1016/j.measen.2024.101353
