Abstract
The 18SIB04 QuantumPascal EMPIR project aims for development of photon-based standards that can replace primary standards of the SI unit of pressure, the Pascal. In this project, four partners simulated the pressure-induced deformation of a given Fabry-Pérot cavity, using various versions of two types of software, COMSOL Multiphysics (R) and ANSYS Workbench. It was demonstrated that, for a given geometry and set of material parameters, simulations of the deformation could be performed by the various partners with such small discrepancies that methodological mistakes of the simulation procedures will solely contribute to a sub-ppm uncertainty in the assessments of refractivity of N<sub>2</sub>.
Highlights
The current realization of the Pascal is based on piston gauges and liquid manometers [1, 2]
The simulations of the cavity deformation were quantized in terms of a pressure-normalized strain of the cavity, i.e. the relative pressureinduced change in length of the cavity for a given pressure, defined as ( L / L) / P, where L is the change in length between the centre points of the reflective surface of the two mirrors induced by the presence of gas and L is the length of the undeformed cavity
There is a tendency that the simulations made using the ANSYS Workbench software consistently predict larger deformations than those made on the COMSOL Multiphysics® software, the difference in simulated deformation performed by the two types of software when the largest numbers of mesh points were used, is only 5 × 10-16 Pa-1, which, for N2, corresponds to a relative uncertainty in the assessed refractivity of solely 0.17 ppm
Summary
The current realization of the Pascal is based on piston gauges and liquid manometers [1, 2]. With the implementation of the refined SIsystem in May 2019, the uncertainty in the Boltzmann constant was eliminated [6] This promises primary measurements limited only by the uncertainty in quantum calculations of molar polarizabilities and some virial coefficients, and in the assessment of axial pressure-induced cavity deformation and gas temperature. This means that, in the long term, such primary standards could provide fast and accurate pressure measurements at a fraction of the present cost
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
