Refractive index Gas Thermometry Data from INRiM originally provided as supplementary data to: D. Madonna Ripa, D. Imbraguglio, C. Gaiser, P. P. M. Steur, D. Giraudi, M. Fogliati, M. Bertinetti, G. Lopardo, R. Dematteis and R. M. Gavioso, “Refractive index gas thermometry between 13.8 K and 161.4 K” Metrologia 58 025008 (2021) Particularly: original microwave data for 8 isotherms with two thermometric gases (He and Ne) with separate records for each pressure investigated along each isotherm; these datasets would allow the interested reader to reproduce and check all the analysis which leads to the (T − T90) determinations obtained in this work; Detailed uncertainty budgets for the calibration of cSPRTs at the ITS-90 fixed points as realized and maintained at INRiM in the range between the triple point of equilibrium hydrogen (T90 = 13.8033K) and the triple point of water (T90 = 273.16K). All the data are listed in a single spreadsheet file: RIGT_INRiM_2021_Original microwave data & thermometry.xls. Additional information regarding the organization of the data is available in a separate text file: RIGT_INRiM_2021_readme.pdf.

This work was carried out within the projects 'Implementing the new Kelvin 2—InK2' and 'Realising the New Kelvin—Real K'. These projects (15SIB02 InK 2) and (18SIB02 Real K) have received funding from the EMPIR programme which is co-financed by the Participating States and from the European Union's Horizon 2020 research and innovation programme.