CCT Task Group on the determination of thermodynamic temperature, T, by non-contact thermometry between the Sn and Ag points with <10 ppm uncertainty (CCT-TG-SNAG)

Terms of reference

• Identify the key issues to be addressed to ensure low uncertainties (<10 ppm in T over the entire range) are attainable; key areas to be investigated are:
  • fixed point construction and characterisation
  • radiometer design and characterisation
  • uncertainty analysis and data fitting
  • the most appropriate direct absolute radiometry approaches
• Prepare a report describing the technical requirements and issues and make a recommendation to the CCT about how to proceed
• If the report is favourable the TG will then develop a work plan leading to T – T90 measurements and assemble consensus values and uncertainties, identifying and working with NMIs capable of, and willing, to perform such measurements
• The chair of this TG will act as a link to CCT WG CT as mirror work is being undertaken in high-temperature acoustic thermometry