Status and performance of the LNE-Cnam Fabry-Perot refractometer

A. Rezki, Z. Silvestri, D. Bentouati, J.-P. Wallerand, C. Guianvarc’h, M. Himbert, P. Otal

Abstract

We present the status of the single-cavity Fabry-Perot interferometer developed at the LNE-Cnam laboratory used for thermodynamic pressure measurements within the range of 100 Pa to 100 kPa. After characterizing the intrinsic parameters of the refractometer, this optical sensor is used to measure the refractivity of nitrogen. Then, using the Lorentz-Lorenz equation and knowing the refractive virial coefficients at 532 nm, it is possible to deduce its density. Measuring the temperature of the gas makes it possible to determine its pressure using an equation of state. </BR>Once the temperature and pressure stability of the gas inside the optical sensor have been achieved at sub-mK and mPa levels, respectively, the expanded uncertainty of the sensor is evaluated to be [(?? ? ?? )^? + (?? × ??^−? ∙ ?)^? ]^(?/?). In order to further decrease this uncertainty, several approaches and solutions are given, leading to more accurate and reliable pressure measurements. The developed optical cavity operates as a high-resolution pressure sensor with an objective of complementing and eventually replacing conventional pressure standards, such as the force-balanced piston gauge and capacitance diaphragm gauge, that are based on the classical definition of pressure.

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IMEKO-TC16-2023-08.pdf

DOI

10.21014/tc16-2023.08

IMEKO TC

TC16 - Pressure and Vacuum Measurement

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