MultiFixRadSoft: A Comprehensive Tool for Primary Relative Radiometric Scale Realization in Radiation Thermometry

Area of Science:

• Metrology and Scientific Instrumentation
• Thermodynamics and Temperature Measurement

Background:

• The new definition of the kelvin requires robust methods for thermodynamic temperature scale realization and uncertainty evaluation.
• Existing methods for radiation thermometry can be complex, necessitating accessible and accurate software solutions.

Purpose of the Study:

• To present a practical implementation of relative primary radiation thermometry (RPRT).
• To introduce MultiFixRadSoft, an open-source software package for thermodynamic temperature scale realization and uncertainty evaluation.
• To validate the software's performance using established fixed points and a linear radiation thermometer.

Main Methods:

• Development of MultiFixRadSoft, an open-source software adhering to the Mise-en-Pratique for the kelvin (MeP-K).
• Utilized ITS-90 metal fixed points and high-temperature fixed points (HTFPs) for scale realization.
• Incorporated automated routines for melting plateau analysis, correction modules (emissivity, nonlinearity, etc.), and Sakuma-Hattori fitting.

Main Results:

• Experimental validation using six fixed points (Cu, Fe-C, Co-C, Pd-C, Ru-C, WC-C) demonstrated software accuracy.
• The software successfully performed ITS-90 extrapolation and flexible calibration schemes (n=1 to n>=3).
• Results showed excellent agreement with manual analyses and published data, confirming algorithm correctness.

Conclusions:

• MultiFixRadSoft provides a unified, transparent framework for data processing, scale realization, and uncertainty analysis in radiometric thermometry.
• The software is a robust and accessible tool for emerging NMIs and industrial laboratories.
• Promotes wider adoption of primary thermodynamic temperature realization methods.