tabletop Kibble balance ; small mass metrology ; kilogram realization ; mass dissemination ; digital calibration certificate (DCC) ; digital metrological expert (DME) ; interlaboratory comparison
Zusammenfassung
An international comparison of three tabletop Kibble balances for the measurement of small mass standards is reported. Two independently manufactured mass sets with mass values of 1 mg, 50 mg, 200 mg, 1 g, 6.626 070 15 g, and 10 g were circulated among the participating institutes. Five of these values correspond to nominal values defined in OIML R 111, while the 6.62607015 g mass was deliberately included as a non-OIML value. The balances, operated at Technische Universität Ilmenau (Germany), Physikalisch-Technische Bundesanstalt (Germany), and the National Institute of Standards and Technology (USA), realize the unit of mass from the fixed numerical value of the Planck constant and apply the Kibble balance principle to milligram- and gram-level mass measurements.
The mass sets were also calibrated independently by laboratories of the manufacturers. Measurements with the three Kibble balances were performed result-blind, without knowledge of the manufacturers’ calibration results or those of the other participants. Data exchange was implemented using Digital Calibration Certificates, and automated evaluation enabled consistent, reproducible, and immediate comparison of results upon unblinding at the Kibble Balance Technical Meeting (November 2025, BIPM).
For each mass value, a comparison reference value was calculated as a weighted mean of the Kibble balance results and compared with the corresponding manufacturer calibration values. A generally good agreement was observed for most masses within the stated uncertainties. However, the comparison is limited by the small number of participants and the significant differences in reported uncertainties. The comparison demonstrates the potential of tabletop Kibble balances for measurements of small mass values with uncertainties at levels relevant to high-accuracy mass metrology, and demonstrates the applicability of digitally supported comparison procedures.
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Rechteinformation
CC BY 4.0 ; Creative Commons Attribution 4.0 License
Themenbereich der Metrologie
Masse und abgeleitete Größen
Forschungsprojekt
The authors express their gratitude to Hao Fang for facilitating the unblinding at the BIPM. They also acknowledge the mass manufacturers, Rice Lake Weighing Systems and Häfner Gewichte GmbH, for their steadfast support throughout the project.
Furthermore, support from the PTB DME/DCC team was essential in adapting the existing infrastructure to this comparison. In particular, we would like to thank Wafa El Jaoua, David Urban, Moritz Gafert, Daniel Hutzschenreuter, Gisa Foyer and Shanna Schönhals for their dedicated contributions. The authors also thank Michael Borys and Dorothea Knopf for their valuable feedback and
insights from mass metrology. The NIST team gratefully acknowledges Brad Suggs and Russell Kauffman from the U.S. Army Primary Standards Laboratory for their contributions to the development of KIBB-g2. Authors from TU Ilmenau were supported by the Deutsche Forschungsgemeinschaft (DFG) under projects 521501354 and the Walter Benjamin Program (546584462). Authors from PTB thank their colleagues for their contributions, in particular, the Scientific Instrumentation Department for fabricating the mechanical parts of the setup.
Zitierung
Konrad, J., Arumugam, K., Rogge, N., Rothleitner, C., Gasca-Aragon, H., Chao, L., Schlamminger, S., Vasilyan, S., & Fröhlich, T. (2026). First international comparison of three different tabletop Kibble balances from 1 mg to 10 g. Metrologia, 63(4), 16 S. https://doi.org/10.1088/1681-7575/ae890c
