This is the summary of the publications prepared in the scope of the project including links to the publications sites:
26th IIR International Congress of Refrigeration, “Dissemination of the redefined kelvin”, August 2023
IMEKO 2024 World Congress, August 2024
The First Newsletter, August 2024
The Second Newsletter, November 2025
The Third Newsletter, July 2026
Published papers
Gao, B., Zhang, H., Kong, X., et al. (2026). Primary thermometry below 25 K: a decade of low-uncertainty measurements linked to the new kelvin. Phil. Trans. R. Soc. A 384: 20240451. https://doi.org/10.1098/rsta.2024.0451
Gavioso, R. M., Steur, P. P. M., Lopardo, G., Imbraguglio, D. (2026). Dissemination of thermodynamic temperature by gas thermometry below 300 K. Phil. Trans. R. Soc. A 384: 20240450. https://doi.org/10.1098/rsta.2024.0450
Imbraguglio, D., Steur, P. P. M., & Gavioso, R. M. (2026). Direct calibration of resistance thermometers between 10 K and 25 K by absolute acoustic gas thermometry. Phil. Trans. R. Soc. A 384: 20250043. https://doi.org/10.1098/rsta.2025.0043
Liu, S., Song, Y., Zhang, H., et al. (2025). Active phase and amplitude temperature control method for cryostat: Active phase and amplitude temperature control method for cryostat: A case in the thermodynamic temperature international comparison system. Appl. Therm. Eng., 258 124562. https://doi.org/10.1016/j.applthermaleng.2024.124562
Song, Y., Zhang, H., Gao, B., et al. (2025). Ultra-stable cryogenic international temperature comparator with microkelvin instability. Metrologia, 62 (2025) 065007 https://doi.org/10.1088/1681-7575/ae1f1d
Song, Y., Zhang, H., Liu, S., et al. (2026). Stability and Calibration Performance of Standard Platinum-Cobalt Resistance Thermometers for Cryogenic Applications. Metrologia, 63 015002. https://doi.org/10.1088/1681-7575/ae2687
Zhang, H., Kong, X., Song, Y., et al. (2025). State-of-the-art comparisons of ab initio calculations of density virial coefficients for helium-4 with measurements. Metrologia, 62 055008. https://doi.org/10.1088/1681-7575/ae012f
Machin, G., Gavioso, R. M., Underwood, R. J., Gaiser, C., Dobre, M., & Martin Hernandez, J.
M. (2025). European partnership in metrology project: Dissemination of the redefined kelvin
(DireK-T). Measurement Sensors. https://doi.org/10.1016/j.measen.2024.101620
Liu, S., Song, Y., Zhang, H., GAO, B., & Han, Z. (2025). Active phase and amplitude
temperature control method for cryostat: A case in the thermodynamic temperature
international comparison system. In Applied Thermal Engineering (Vol. 258, Numéro Part A,
p. 124562). Zenodo. https://doi.org/10.5281/zenodo.15297343
Zhang, H., Song, Y., Kong, X., GAO, B., Plimmer, M., & Pitre, L. (2025). Repeatability of a
primary thermometer and calibration of resistance thermometers between 5 K and 25 K at
the sub-millikelvin level. In Metrologia: Vol. 62 015005 (Numéro 1, p. 015005). Zenodo.
https://doi.org/10.5281/zenodo.15297581
Liu, S., Yaonan, S., GAO, B., Zhang, H., & Han, Z. (2025). Achieving High Stability in Cryostat: A
Study on Optimal Thermal Link Parameters. In International Journal of Refrigeration: Vol.
Volume 167 (Numéro 2024, p. 13-22). Zenodo. https://doi.org/10.5281/zenodo.15295276
Conference presentations
Results from the DireK‑T project were presented at the TEMPMEKO–ISHM 2025 Conference held in Reims, France, from 20 to 24 October 2025 (https://www.tempmeko-ishm2025.com/inscriptions/en/scientific-program/detailed-program/). Project partners contributed to the sessions OP‑01 – Thermodynamic Temperature Determinations; in Memory of Mike Moldover, OP‑13 – Thermodynamic Temperature Determinations, and OP‑25 – Dissemination of the Redefined Kelvin (DireK‑T Project). These presentations showcased recent developments in primary thermometry, thermodynamic temperature determination, and strategies for the dissemination of the redefined kelvin, demonstrating the significant scientific progress achieved through the DireK‑T project.
Žužek, V., Kropej, R., Janežič, A., & Bojkovski, J. (2025). Establishing Traceability of Capsule Type Thermometers in Scope of DireK‑T Project at MIRS/UL‑FE/LMK. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Shivagan, D. D., Babita, Pant, U., Meena, H., Gupta, G., & Bapna, K. (2025). Thermal Optimizations for Development of Acoustic Gas Thermometry at CSIR‑NPL, India. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025
Gavioso, R. M., Steur, P. P. M., Lopardo, G., Rinolfi, S., Santoro, F., & Imbraguglio, D. (2025). Thermodynamic Temperature Measurements by Acoustic Gas Thermometry Between 10 K and 160 K. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Zhang, H. Y., Song, Y. N., Kong, X. J., Gao, B., & Pitre, L. (2025). Relative Refractive-Index Gas Thermometry and Thermodynamic Temperature Wire Scale from 5 K to 25 K. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Kong, X., Liu, S., Song, Y., Zhang, H., Guo, W., Gao, B., & Pitre, L. (2025). Towards Direct Realisation of the ITS‑90 in a Primary Gas Thermometer Between 2 K and 5 K. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Gavioso, R. M., Gaiser, C., Martin, M. J., Dobre, M., Underwood, R., & Machin, G. (2025). The DireK‑T Project for Dissemination of Thermodynamic Temperature. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Voldán, M., Gavioso, R. M., & Mahovský, D. (2025). Implementing Acoustic Gas Thermometry at CMI in the Temperature Range 233 K to 303 K. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Gaiser, C., & Fellmuth, B. (2025). Experiment and Theory Hand in Hand – A Re‑evaluation of DCGT Data with ³He at 2.5 K and 3.2 K. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Yang, I. (2025). Thermodynamic Temperature Measurement Using Acoustic Gas Thermometry at KRISS. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Pitre, L., Tauzin, C., & Sparasci, F. (2025). Evaluating Different Methods in Acoustic Frequency Measurement: Advancing Towards a Practical AGT. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Tsai, S. F., & Underwood, R. (2025). Acoustic Gas Thermometry with a Cylindrical Resonator Near Room Temperature. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Rourke, P. M. C., Levesque, M. B., & Todd, A. D. W. (2025). NRC AGT+RIGT System: Vacuum Measurements and Auxiliary Isotherm Results. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Xu, L., Feng, X.-J., Lu, X.-F., & Zhang, J.-T. (2025). Progress on the Determination of T−T90 by Cylindrical Acoustic Gas Thermometry up to 1000 K. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Pant, U., Sparasci, F., Plimmer, M. D., & Pitre, L. (2025). Progress on Measurement of the T−T90 Using Acoustic Gas Thermometry of Helium‑4 with a Large‑Volume Quasi‑Spherical Resonator. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Gao, B., Zhang, H. Y., Guo, W. X., Kong, X. J., Song, Y. N., Liu, S. Q., Luo, E. C., & Pitre, L. (2025). Implementing New Kelvin at Temperatures Below 25 K. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.Kowal, A., Nikonkov, R., Szklarz, G., et al. Advancements in Thermodynamic Temperature Dissemination: Progress in the DireK‑T Project. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Underwood, R. (2025). The Gas‑Shell Interaction in Acoustic Resonators and Implications for Practical Primary Thermometry. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
Dobre, M., Voldán, M., & Mahovský, D. (2025). Overcoming Challenges in Using ITS‑90 Fixed Point Cells for CSPRT Calibration: Lessons Learned. Presentation at TEMPMEKO–ISHM 2025, Reims, France, 20–24 October 2025.
C. Gaiser, The challenges of primary thermometry from 300 K to 1235 K, presentation at The
Royal Society – Theo Murphy Meeting – The redefined kelvin: progress and prospects, 24 – 25
February 2025
R. Gavioso, Dissemination of thermodynamic temperature below 300 K, presentation at The
Royal Society – Theo Murphy Meeting – The redefined kelvin: progress and prospects, 24 – 25
February 2025
B. Gao, Ultra-low uncertainty primary thermometry below 25 K, presentation at The Royal
Society – Theo Murphy Meeting – The redefined kelvin: progress and prospects, 24 – 25
February 2025
X. Feng, Progress on future temperature dissemination using high temperature acoustic gas
thermometry, presentation at The Royal Society – Theo Murphy Meeting – The redefined
kelvin: progress and prospects, 24 – 25 February 2025
G. Machin, M. Dobre, R. Gavioso, C. Gaiser, M-J. Martin, R. Underwood, “Dissemination of
the redefined kelvin”, poster presented at 26th IIR International Congress of Refrigeration:
Paris , France, August 21-25, 2023.
R. Gavioso, M. Dobre, C. Gaiser, R. Underwood and G. Machin, “Dissemination of the
redefined kelvin”, poster presented at 22nd Symposium on Thermophysical Properties,
Boulder, CO, USA, June 23–28, 2024
G. Machin, R. Gavioso, M. Dobre, C. Gaiser, M-J. Martin, R. Underwood, “European
Partnership in metrology project: Dissemination of the redefined kelvin (DireK-T)”, paper
accepted for presentation at XXIV IMEKO World Congress “Think Metrology” August 26 – 29,
2024, Hamburg, Germany