Realising the redefined kelvin

Work Packages

In order to the first time show that primary thermometry can be used for temperature realisation and dissemination at high temperatures (>1300 K) and low temperatures (<25 K) with uncertainties on a par with ITS-90 the research is divided on the following work packages.

WP1: Realisation and dissemination of the redefined kelvin above 1300 K

  • Four high-temperature fixed points, HTFPs, (Fe-C (1426 K), Pd-C (1765 K), Ru-C (2226 K) and WC-C (3020 K) to cover the whole temperature range above the freezing temperature of copper.
  • Allow the application of the HTFPs for the Mise en Pratique of the kelvin with a significantly improved uncertainties compared to the current scheme based on the ITS-90

Target standard-uncertainties of less than 0.1 K at the Fe-C up to 0.4 K at the WC-C.

WP2: Realisation and dissemination of the kelvin below 25 K

  • Extend the working range of primary thermometry to the temperature range from 1 K to 25 K for direct realisation and dissemination of thermodynamic temperatures.
  • Demonstrate smooth overlap with the primary methods developed for the PLTS-2000 <1 K.

The target uncertainty is 1 % and less for the measurement of thermodynamic temperatures.

WP3: Extending the life of the International Temperature Scale of 1990

  • Extend the life of the current defined scale (ITS-90) in the Standard Platinum Resistance Thermometer (SPRT) range –248.6 °C to 962 °C.
  • Construct and metrologically characterise two alternative high performance fixed points, the SF6 and the CO2 triple points, suitable for the calibration of long stem SPRTs.

The target is to reducing the ITS-90 non-uniqueness uncertainty by approximately 30 %.

WP4: Facilitating full range primary thermometry

  • Reduce the uncertainty of several primary thermometry methods which are included in the Mise en Pratique for the definition of the kelvin, namely AGT, DCGT, RIGT,
  • Extend the range of application of these methods beyond that previously demonstrated.

Revised uncertainty budgets for three primary thermometry methods: AGT, DCGT, and RIGT.

WP5: Creating Impact

The aim of this work package is to establish means for effective exploitation for the project outcomes by

  • Ensuring a seamless transition to the new kelvin throughout the world
  • Facilitating the take up of the developments by the measurement supply chain.