Force measurement and weighing technology

TU Ilmenau

Forces in the nanonewton range are typically measured using small bending beams (cantilevers). The deflection of a cantilever is measured and the force is calculated with the stiffness. However, there is a considerable variation in stiffness due to manufacturing processes, so that each cantilever must be calibrated individually. At TU-Ilmenau, a calibration device has been developed that pushes the cantilever onto a precision scale and simultaneously measures its deflection. The slope of the force-displacement-curve is then used to determine the stiffness with an accuracy of approx. 1%.

Literature:

• Diethold, C., et al. "Determination of force to displacement curves using a nanopositioning system based on electromagnetic force compensated balances." Measurement 51 (2014): 343-348.

• Kühnel, Michael, et al. "National comparison of spring constant measurements of atomic force microscope cantilevers." IMEKO TC3, TC5 and TC22 International Conference 2017. 2017.

• Dannberg, O., et al. “Entwicklung einer Cantileverkalibriereinrichtung.” tm-Technisches Messen (2020)

TU Ilmenau

The use of the radiation pressure of a laser field as an effect of the momentum transfer of the absorbed and re-emitted photons from the ultra-high reflective mirrors, suggests new technological possibility for metrology to generate very small calibration forces or to calibrate the optical power of lasers with great accuracy and precision directly traceable to Planck constant. In this newly re-established age of quantum metrology the measurements of quantum-electrical quantities within the redefined International System of Units (SI) guide many high-tech developments.

In the project the multi-reflection configuration of the laser beam is employed inside the macroscopic optical cavity that consist of the mirrors with near to ideal reflectivity. In such a way a force of, for example, several hundred nN are generated from just 1 W laser power when the laser beam undergoes 20 multi-reflections.  Otherwise, the forces generated during a single laser light reflection scales in the order of only several nN.

Literature:

• S. Vasilyan, T. Fröhlich, und N. Rogge. "Deploying the high-power pulsed lasers in precision force metrology - Towards SI traceable and practical force quantization by photon momentum" tm - Technisches Messen, vol. 89, no. 11, 2022, pp. 757-777. https://doi.org/10.1515/teme-2022-0080
• PTB news 2/2022
• S. Vasilyan, M. López, N. Rogge, M. Pastuschek, H. Lecher, E. Manske, S. Kück, und T. Fröhlich, "Revisiting the limits of photon momentum based optical power measurement method, employing the case of multi-reflected laser beam." Metrologia, 58(1):015006, (2021). https://doi.org/10.1088/1681-7575/abc86e
• S. Vasilyan, N. Rogge, T. Fröhlich, “Metrology in direct photon momentum measurement“, - In: Messunsicherheit - Prüfprozesse 2019. - Düsseldorf : VDI Verlag GmbH, (2019), S. 193-205
• E. Manske, T. Fröhlich, S. Vasilyan, ”Photon momentum induced precision small forces: a static and dynamic check“, Meas. Sci. Technol. 30 105004, 2019. DOI: 10.1088/1361-6501/ab257e.

• S. Vasilyan, T. Fröhlich, E. Manske, “Total momentum transfer produced by the photons of a multi-pass laser beam as an evident avenue for optical and mass metrology”, Optics Express, 25, 20798-20816, 2017. DOI: 10.1364/OE.25.020798.

ari

Since the redefinition in May 2019 the unit of mass, the kilogram, is defined by a fixed value of the Planck constant. In a joint project between the Institute for Process Measurement and Sensor Technology and the Physikalisch-Technische Bundesanstalt, a balance is being developed that can be used for mass determinations in accordance with the new definition.

The so-called Planck-Balance aims to achieve uncertainties comparable to class E1 weights according to OIML R111 within a weighing range of 1 mg to 1 kg. Due to its compact design and the low price compared to conventional Kibble balances, it is particularly interesting for industrial applications.

Literature:

• S. Vasilyan, N. Rogge, C. Rothleitner, S. Lin, I. Poroskun, D. Knopf, F. Härtig, und T. Fröhlich, "Der Entwicklungsfortschritt der Planck-Waage 2 (PB2): Eine Kibble-Tischwaage für die Massenkalibrierung von Gewichten der Klasse E2". tm - Technisches Messen, 88(12):731-756, (2021). https://doi.org/10.1515/teme-2021-0101
• S. Lin, C. Rothleitner, N. Rogge, T. Fröhlich. Influences on amplitude estimation using three-parameter sine fitting algorithm in the velocity mode of the Planck-Balance. Acta IMEKO. September 2020, Volume 9, Number 3, 40-46. ISSN: 2221-870X. doi: http://dx.doi.org/10.21014/acta_imeko.v9i3.781
• Fröhlich, T., Rogge, N., Vasilyan, S., Rothleitner, C., Günther, L., Lin, S., Hilbrunner, F., Knopf, D., Härtig, F., & Marangoni, R. (2020). Neue Wege zur Kalibrierung von E2-Massenormalen und Darstellung von Kräften bis 10 N, tm - Technisches Messen, 87(4), 280-293. doi: https://doi.org/10.1515/teme-2019-0143
• Rothleitner, C., Schleichert, J. et al., The Planck-Balance—using a fixed value of the Planck constant to calibrate E1/E2-weights, Measurement Science and Technology, vol. 29, no. 7, 2018, p. 074003.
• C. Rothleitner, J. Schleichert, S. Vasilyan, N. Rogge, L. Günther, F. Hilbrunner, I. Rahneberg, D. Knopf, T. Fröhlich, F. Härtig. First Results Using the Planck-Balance. In 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018), IEEE, 8-13 July 2018, DOI: 10.1109/CPEM.2018.8500904

In a joint project of the Institute of Process Measurement and Sensor Technology and Sartorius AG, a 1 kg mass comparator was developed for passing on the unit of mass. It allowed verifying a previously unattained precision - a standard deviation of less than 50 ng in a vacuum. In the "Avogadro project" which is designed to display the unit of mass, a silicon sphere is connected to original kilogram and thus Avogadro constant is determined. The highly accurate 1 kg prototype mass comparator can measure both, spheres and cylinders with the utmost precision for the first time in weighing technology. Since the revision of the International System of Units (SI) in 2019, the Planck constant “h” defines the kilogram.

Literature:

• Schreiber, M., et al. “Quantification of free convection effects on 1 kg mass standards.” Metrologia, 2015, 52. Jg., Nr. 6, S. 835.
• Fehling, T., Fröhlich T. Heydenbluth, D., “Design and Performance of the New Sartorius 1kg-Prototype Mass Comparator for High Precision Mass Determination and Research Applications.” In: Transverse Disciplines in Metrology: Proceedings of the 13th International Metrology Congress, 2007—Lille, France. London, UK: ISTE, 2009. S. 657-668.
• Fehling, T., Fröhlich T. Heydenbluth, D., “Design and performance of the new Sartorius robot-system.” In: Proceedings of the 20th TC3, 3rd TC16 and 1st TC22 international conference cultivating metrological knowledge, IMEKO. 2007. S. 27-30.
• Fröhlich, T., et al. “Vacuum transfer system for loading the Sartorius prototype mass comparator CCL1007.” In: Proceeding of IMEKO. 2010. S. 22-25.
• Borys, M., et al. “Design and performance of the new Sartorius 1 kg vacuum mass comparator at PTB.” In: XVIII Imeko World Congress, Rio de Janeiro, Brazil. 2006.