Primary Acoustic Gas Thermometer

Purpose and goal

The goal of the project is to construct an acoustic gas thermometer that will be used to realize the unit of thermodynamic temperature, the kelvin. The focus will be on making the thermometer practical, which means, among other things, that it should be possible to fit it into an existing liquid bath, which places a limitation on its size. It also means that it should be usable at somewhat higher temperatures than those traditionally used in measurements with acoustic gas thermometers.

Expected effects and result

The aim is to strengthen the NMI with a new resource and increased competence. A primary implementation of kelvin also enables participation in international collaborations, comparisons and project. There is a strong expectation that primary thermometers will move towards more practical equipment and that they will replace the current temperature scale. Therefore, it is important for the NMI to follow developments in order to continue to be able to meet the needs of industry in the future.

Planned approach and implementation

The thermometer will be designed as a cylinder to be compatible with existing equipment and to simplify manufacturing. Initially in the project, the requirements for the equipment will be specified, especially the acoustic measurement and the length measurement. The practical parts of the thermometer will then be designed and manufactured. Finally, it will be tested against existing references and a measurement uncertainty budget will be set up.