Towards reliable and traceable quantum-based pressure measurements

Accurate pressure measurements are necessary in many sectors: climate, medicine, manufacturing, energy and research. Flight safety, operational safety at power plants and prevention of leaks in connection with toxic waste or nuclear waste are some examples.

Current methods for realising the SI unit of pressure, pascal, rely on applying a known force to a known area. When the SI system was revised in May 2019 and Boltzmann's constant was given a fixed value, an alternative path to realizing the pascal opened, by measuring the refractive index and temperature of a gas. Such a realisation of pascal, and other similar quantum-based approaches included in this project, does not rely on weights or moving parts, but instead exploits the properties of gases.

The aim of the project is to establish a European infrastructure for the new technologies, reduce uncertainties and try to improve the efficiency of calibration chains.

Building on previous research

RISE has long been a driving force in the work to develop the new instruments and methods together with Umeå University, among other things through a joint doctoral project and in the European project QuantumPascal, which was a direct predecessor to this project.

Quantum-based systems and methods

The project will develop the traceability of pascal through quantum-based instruments and methods, covering the range 1 Pa to 1 MPa. The new instruments and methods will also be evaluated in practical applications.

A difference to the previous QuantumPascal project is that the project will focus on nitrogen as a measuring gas. Nitrogen is already widely used today for various purposes, but the gas's thermodynamic and electrodynamic properties are relatively unexplored. Determining the properties of the gas and thus increasing the reliability of the measurements will be an important issue for the project.

European cooperation

The project is led by the German PTB and involves many partners from several European countries. RISE leads the largest work package, which involves developing methods and measuring instruments based on a technique known as Fabry Pérot refractometry. We also participate in other work packages, including the work to develop a system for measuring dynamic pressure based on Rayleigh scattering.