Profile
Working group 7.55 "Photonic pressure measurement" deals with the quantum-based realization of the pressure scale. Measurement methods based on the determination of gas density and the fundamental and therefore constant properties of gases are particularly useful in the range below normal pressure (105 Pa).
The focus of research and development is on laser-optical measurements of the density and temperature of selected gases to determine partial pressures and to realize the pressure scale in the range from high vacuum to normal pressure.
In addition, a compact primary standard for pressure measurements in ultra-high vacuum (pressures < 10-6 Pa) is being developed on the basis of cold atoms in collaboration with the University of Bremen and WG 7.54 Vacuum Metrology.
The photonic realization of the Pascal represents an innovative challenge which can currently only be implemented in cooperation. Accordingly, there is also interdepartmental and close cooperation with other working groups and departments within PTB: for example, for the pressure measurement (cooperation with 7.54 and 3.33), the thermostatization of the apparatus and temperature determination of the gases as well as the consideration of real gas effects (cooperation with 7.4), the measurement of the beat frequencies of the lasers stabilized on cavities among each other and in comparison with frequency standards, FEM simulations and optimization of the design with respect to length stability (cooperation with 4.31 and 5.2).
There is also close cooperation with other metrological institutes and universities outside PTB, for example within the framework of the EU projects: "MQB-Pascal" and "QuantumPascal", which are (or were) coordinated by the working group.
https://www.mqb-pascal.ptb.de/ (2023-2026)
https://www.ptb.de/empir2019/quantumpascal/ (2019-2022)
Research/Development
The density-based, photonic representation of the Pascal has the prospect of significantly lower uncertainties, especially with the introduction of the new SI. For this purpose, the focus is on the design and implementation of two measurement methods:
- Refractive index measurement on high purity helium, argon and nitrogen for primary density or pressure measurements with lowest uncertainties in the range of 10 Pa to 100 kPa (fine vacuum to normal pressure).
- Absorption measurement on carbon dioxide, water vapor and other gases in the range from 1 mPa to 10 Pa (high vacuum to fine vacuum) for the determination of partial and absolute pressures.
Information
The team of WG 7.55 'Photonic Pressure Measurement'
Dr. Dr. Tom Rubin (Head of group)
André Kussicke (PHD student with focus: absorption spectroscopy)
Sara Gehauf (PHD student with focus: refractometry and cold atoms)
Patrick Asbahr (former member with focus: refractometry)
Sandra Lukanek (former member)
Selected Publications:
- Johan Zakrisson, Isak Silander, André Kussicke, Tom Rubin, Martin Zelan, and Ove Axner, Effect of absorption of laser light in mirrors on Fabry-Perot based refractometry, Optics Express, Vol 32, (2024), Doi: https://dx.doi.org/10.1364/OE.528261
- Clayton Forssén, Isak Silander, Johan Zakrisson, Eynas Amer, David Szabo,Thomas Bock, André Kussike, Tom Rubin, Domenico Mari, Stefano Pasqualin, Zaccaria Silvestri, Djilali Bentouati, Ove Axner, and Martin Zelan, Demonstration of a Transportable Fabry–Pérot Refractometer by a Ring-Type Comparison of Dead-Weight Pressure Balances at Four European National Metrology Institutes, Sensors, Vol. 21(1), p. 7 (2023), Doi: https://doi.org/10.3390/s24010007
- Tom Rubin, Marian Sarrazin, N.F. Zobov, Jonathan Tennyson, Oleg Polyansky, Sub-percent accuracy for the intensity of a near-infrared water line at 10,670 cm−1: experiment and analysis, Molecular Physics, p. e2063769 (2022) Doi: 10.1080/00268976.2022.2063769
- Tom Rubin, Isak Silander, Johan Zakrisson, Ming Hao, Clayton Forssén, Patrick Asbahr, Matthias Bernien, André Kussicke, K Liu, Martin Zelan, Ove Axner, Thermodynamic effects in a gas modulatedInvar-based dual Fabry–Perot cavity refractometer, Metrologia, 59. , Nr. 3, p. 035003 (2022), Doi: 10.1088/1681-7575/ac5ef9
- JOUSTEN, Karl, et al., Perspectives for a new realization of the pascal by optical methods, Metrologia, (2017), 54. Jg., Nr. 6, S. S146. https://iopscience.iop.org/article/10.1088/1681-7575/aa8a4d/pdf
Selected Innovations:
- Optische Langwegzelle mit minimiertem Strahlversatz: https://patents.google.com/patent/DE102016102431B3/de
- Optische Langwegzelle mit deutlich erhöhter Weglänge (Rubin-Zelle): https://patents.google.com/patent/DE102016102430B3/de