The increasing demand for thermal management in various industries (energy, micro and nanoelectronics…), has driven the need for reliable thermal characterization techniques at micro- and nanoscale. Scanning thermal microscopy (SThM) is a valuable tool for thermal properties characterization and heat transfer mechanisms investigation at these scales. However, some metrological aspects remain a challenge for quantitative and traceable thermal conductivity measurement with the SThM technique. The aim of this work is to improve the metrology associated with the SThM thermal conductivity measurement for quantitative, traceable, and reliable measurements.

A key contribution of this work is the establishment of a new 3D FEM model (three-dimension model established with finite elements method) for the second generation of the Pd probe. This new model aims to describe more accurately the heat dissipation in the probe and the different heat transfer mechanisms occurring between the probe, the sample and the environment with different measurement configurations (vacuum, air, and probe in contact with the sample or out of contact). Simulation results highlight the respective contribution of main influencing parameters. These reveal notably the critical influence of the interfacial thermal resistance on the thermal response and on the sensitivity of the technique both in air and in vacuum environments. The ballistic heat conduction regime (at the contact), which is generally neglected in existing models in the literature, was integrated into the 3D model. The simulation study highlights the necessity to consider this heat transfer when the measurements are done in vacuum.

A comparative study between the 3D FEM model and an analytical model used experimentally to calibrate SThM probes evaluates the applicability of the analytical approach for thermal conductivity measurements and highlights its limitation and potential improvement.

The experimental part of this work focuses on improving the experimental setup developed at the French National Metrology Institute and measurement protocols for a more accurate and repeatable measurement. Additionally, an experimental calibration curve is established and the associated uncertainty is evaluated with a new approach.

The results have shown that the improvements of the setup and the measurement protocols have reduced the uncertainty associated to the measurand thus reducing the uncertainty associated with the thermal conductivity estimation. Experimental analysis shows that quantitative and traceable measurements of thermal conductivity (for samples where heat transfer is predominantly diffusive) using the SThM technique are possible for low thermal conductivity materials (currently limited to the range from 0.187 W.m^-1.K^-1 to 10 W.m^-1.K^-1) with an relative associated uncertainty lower than 20% (k=2).

finite element method modeling, uncertainty evaluation, thermal conductivity, scanning thermal microscopy (SThM), resistive probe, nanoscale.

Full document (EN) : Tel-05386832

The thesis focuses on the metrology of temperatures below 1 kelvin, a range where quantum effects strongly influence the physical properties of fluids and materials. Reliable thermometry, closely aligned with thermodynamic temperature, is essential in this domain, both for fundamental research and for technological applications, particularly with the rise of low-temperature space experiments and quantum technologies operating at millikelvin temperatures.

The International Temperature Scale of 1990 (ITS-90) is defined down to 650 mK. Below this, the only internationally recognised reference is the Provisional Low Temperature Scale of 2000 (PLTS-2000), which covers the range from 0.9 mK to 1 K, based on the universal melting curve of ultrapure helium-3. In parallel, secondary thermometers calibrated against PLTS-2000 play a key role in disseminating this scale to laboratories that do not have direct access to measurements of the helium-3 melting curve.

The primary objective of this work was to implement PLTS-2000 at LNE-Cnam, ensuring the rigorous measurement of the helium-3 melting curve and its relationship with temperature in accordance with the recommendations for the scale. Secondly, a comparison was carried out with a magnetic field fluctuation thermometer (MFFT), a relative primary thermometer that provides independent access to thermodynamic temperature via the measurement of thermal magnetic noise. Finally, two secondary thermometers commonly used below 1 kelvin, a paramagnetic salt thermometer (CMN) and a superconducting reference device (SRD1000), were calibrated against PLTS-2000, and their performance assessed in terms of stability and reproducibility.

The main results of this work are :

1. The most-accurate realization of PLTS-2000 achieved with the relative uncertainty u_r(T₂₀₀₀) ≈ 0.025×[T₂₀₀₀/(1 mK)]−0.82 in the range 8 mK to 800 mK. Two other realizations (using different melting curve thermometers) had uncertainties approximately four times larger.

2. We calibrated a commercially-manufactured magnetic field fluctuation thermometer (MFFT) at a fixed point temperature (λ point or melting curve minimum) and then achieved the relative uncertainty u_r(T_MFFT) ≈ 0.002 from 0.9 mK to the calibration temperature. This performance exceeds the manufacturer’s specification by a factor of 5.

3. By direct comparison, we showed the MFFT was consistent with PLTS-2000, within combined uncertainties, throughout the range. This agreement reinforces the validity of PLTS-2000. It also demonstrates that a laboratory can achieve TPLTS-2000 with the small uncertainty u_r(T_MFFT) ≈ 0.002 without installing a complex melting curve thermometer.

4. We detected a temperature-independent offset : T_MFFT−T₂₀₀₀ ≈ 0.2 mK. We attribute the offset to external noise from an unidentified source that affected the MFFT. The offset implies that a laboratory that uses a calibrated MFFT to approximate TPLTS-2000 should also use a check standard such as a superconducting reference device that could detect changes in an offset.

5. We conducted detailed studies of the transition temperatures Tc of three commercially manufactured superconducting reference devices SRD 1000. They led to our:

— confirming that the apparent values of T_c are sensitive to residual magnetic fields, measuring

currents, and noise filters;

— fitting the entire transition curve of non-ideal transitions to obtain more precise values of T_c than alternative methods of identifying T_c;

— measuring the long-term (20 years) stability of Tc of six materials in one device;

— demonstrating that the variation of T_c among different devices is much larger than the precision of determining T_c. Therefore, individual calibration can improve the accuracy of T₂₀₀₀ dissemination via SRD 1000.

6. We verified that a particular CMN thermometer has high resolution and a short response time. This thermometer is well suited for temperature control at ultra-low temperatures.

7. The optimal solder for delicate cryogenic lines is a silver-tin alloy containing 6% silver.

This body of work contributes to strengthening the metrological framework of thermometry below 1 kelvin at LNE, reinforcing both the validation of PLTS-2000 and its practical dissemination within the cryogenic measurement community.

metrology, low temperature thermometry, PLTS-2000, Helium-3 melting curve, primary thermometry, secondary thermometry, magnetic field fluctuation thermometry, CMN thermometer, superconducting reference device, dilution refrigerator.

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KRENEK S., EISERMANN R., FAILLEAU G., LU X., THOMAS P.J., KJELDSEN H. and ANHALT K., “Fibre-optic thermometry to support the clean energy transition”, tm - Technisches Messen, 2025, 92, 9-10, DOI: 10.1515/teme-2025-0044.

LU X., CHRISTENSEN J.B., THOMAS P.J., FAILLEAU G., EISERMANN R., HICKE K. and KRENEK S., “Fiber artefact for performance evaluation of time domain distributed fiber sensor interrogators”, Measurement Science and Technology, 2025, 36, 11, DOI: 10.1088/1361-6501/ae214e.

MUELLER I., GIRARD F., FLORIO M., NASIBLI H., GÖZÖNÜNDE C., MARTIN M.J., MANTILLA J.M., SADLI M., KOSMALSKI S., LU X., BUENGER L., ANHALT K. and HUTZSCHENREUTER D., “CCT K11 blackbody temperature from 34.5 °C to 41.5 °C – Reporting and evaluation in the EURAMET loop using digital calibration certificates”, Measurement: Sensors, 2025, 38, DOI: 10.1016/j.measen.2024.101626.

SONG Y., ZHANG H., GAO B., LI G., LIU S., KONG X. and PITRE L., “Ultra-stable cryogenic international temperature comparator with microkelvin instability”, Metrologia, 2025, 62, 6, DOI: 10.1088/1681-7575/ae1f1d.

TALLAWI B., ROMIEU K. and FAVREAU J.O., “Dynamic metrology in practice: From concepts to calibration services”, Measurement: Sensors, 2025, 38, DOI: 10.1016/j.measen.2024.101642.

TAUZIN C., PLIMMER M., SPARASCI F., GUO W., WHITE D.R. and PITRE L., “Comparison of PLTS-2000 and the Magnetic Field Fluctuation Thermometer at LNE-Cnam”, Metrologia, 2025, 62, 4, DOI: 10.1088/1681-7575/ade4d0.

KOZLOVA O., “Thermometry with optomechanical resonators: from photonic and noise thermometry towards quantum thermometry”, Oral presentation, Royal Society of London - The redefined kelvin: progress and prospects - Theo Murphy Meeting, Glasgow, United Kingdom, 24-25 February 2025.

SADLI M., “Full-range relative thermodynamic temperature”, Oral presentation, Royal Society of London - The redefined kelvin: progress and prospects - Theo Murphy Meeting, Glasgow, United Kingdom, 24-25 February 2025.

TALLAWI B., “Advanced techniques for moisture and water content analysis in solids: enhancing industrial process control and product quality”, Oral presentation, International Metrology Congress CIM 2025, Lyon, France, 11-14 March 2025.

TALLAWI B., “Advancing calibration techniques for dynamic measurements”, Oral presentation, International Metrology Congress CIM 2025, Lyon, France, 11-14 March 2025.

FERREUX E., LOUBAR F., STESHCHENKO T., KOZLOVA O., MARTEL T., GHORBEL I., GIGGIO L.A., COMBRIÉ S., DE ROSSI A., SPARASCI F., PITRE L., BRAIVE R., BRIANT T. and BRIAUDEAU S., “Towards quantum thermometry with optomechanics”, Oral presentation, MBL 2025, Delft, The Netherlands, 1-3 April 2025.

KOZLOVA O., “Photonic and Quantum Sensors for Practical Integrated Primary Thermometry”, Oral presentation, MBL 2025, Delft, The Netherlands, 1-3 April 2025.

SADLI M. and BOURSON F., « Bonne pratique de l’étalonnage de pyromètres », Oral presentation, 10th International Metrology Conference (Cafmet), Hammamet, Tunisia, 22-24 April 2025.

SADLI M., « La température thermodynamique et la nouvelle définition du kelvin : Mise en pratique, un double éco-système T et T₉₀ », Oral presentation, 10th International Metrology Conference (Cafmet), Hammamet, Tunisia, 22-24 April 2025.

SADLI M., BOURSON F., PITRE L. and SPARASCI F., « Mise en pratique du Kelvin au LNE-CNAM », Oral presentation, 10th International Metrology Conference (Cafmet), Hammamet, Tunisia, 22-24 April 2025.

SADLI M., KNAZOVICKA L., PAVLASEK P., NASIBLI H., BOURSON F. and FALNES OLSEN A.A., « Projet de recherche MultiFixRad pour établir une échelle de température thermodynamique basée sur des points fixes à haute températureProjet de recherche MultiFixRad pour établir une échelle de température thermodynamique basée sur des points fixes à haute température », Oral presentation, 10th International Metrology Conference (Cafmet), Hammamet, Tunisia, 22-24 April 2025.

TALLAWI B., FAVREAU J.O. and ROMIEU K., “Enhancing Dynamic Measurement Methods: From Concepts to Calibration Standards”, Oral presentation, SMSI 2025 - Sensor and Measurement Science International, Nuremberg, Germany, 6-8 May 2025, DOI: 10.5162/SMSI2025/D4.3.

SADLI M., « Mise-en-Pratique de la nouvelle définition du kelvin: quelle stratégie pour garantir l’équivalence et la traçabilité au niveau international ? », Oral presentation, Journée de la métrologie 2025 - ILNAS, Esch-sur-Alzette, Luxembourg, 15 May 2025.

GAO B., ZHANG H., KONG X., SONG Y., LUO E. and PITRE L., “Single-pressure refractive-index gas thermometry below 25K”, 150th anniversary of the Metre Convention and the BIPM - Accepted Abstracts (poster online), 20 May 2025, https://thebipm150.org/posters-online/.

HAY B., BEAUMONT O., FLEURENCE N., DAVÉE G. and HAMEURY J., “Recent developments for measuring high-temperature thermal diffusivity of Advanced materials used for Energy production”, 150th anniversary of the Metre Convention and the BIPM - Accepted Abstracts (poster online), 20 May 2025, https://thebipm150.org/posters-online/.

PITRE L., SPARASCI F., PLIMMER M.D., HIMBERT M.E. and SADLI M., “Redefining Exactitude at LNE-Cnam: The Last and Most Accurate Boltzmann Constant Measurement”, 150th anniversary of the Metre Convention and the BIPM - Accepted Abstracts (poster online), 20 May 2025, https://thebipm150.org/posters-online/.

KOZLOVA O., “European joint research project: Photonic and Quantum Sensors for Practical Integrated Primary Thermometry (PhoQuS-T)”, Poster, DIM QuanTiP annual meeting, Villetaneuse, France, 27 May 2025.

BOURSON F., BOJKOVSKI J., BROBERG P., CLAUSEN S., GÖZÖNÜNDE C., HOLMSTEN M., KNAZOVICKA L., MANUIR M.I., MLACNIK V., NÆSBY RASMUSSEN A., NASIBLI H., OPEL K., PAVLASEK P., SADLI M., ZUZEK V. and OLSEN Å.A.F., “Key comparison Euramet.T-K10: Realisation of the ITS-90 scale over the range from the Ag fixed-point to 2600 °C”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

BOURSON F., SADLI M. and BRIAUDEAU S., “Evaluation of the uncertainties of a batch of silver and copper fixed point cells for ITS-90 realisation”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

CHIODO N., GEORGIN E. and BERG R.F., “Measurement of the enhancement factor in gases at LNE-CNAM: experimental results and analysis”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

DIDI-ALAOUI I., AMRANE M.A., SPARASCI F. and PITRE L., “Development of a cryogenic transfer comparator below 30 K (CTC below 30 K)”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

FAILLEAU G., BEAUMONT O., LECOEUCHE V. and HAMEURY J., “Calibration of distributed temperature sensing systems using optical fibres for high temperature measurements”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

FAVREAU J.O., GEORGIN E. and MERLONE A., “Use of heat pipes for industrial calibration of platinum resistance thermometers”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

FERNICOLA V., ARPINO F., BELTRAMINO G., BENYON R., BOGGIO S., CASTRILLO A., CHIODO N., CORTELLESA G., CUCCARO R., DESCHERMEIER R., EBERT V., ENESCU D., FATEEV A., FERNANDEZ-VICENTE T., GARCÍA GALLEGOS J., GEORGIN E., GIANFRANI L., HAWES N., HUDOKLIN D., GLIESE P.J., KLEIN T., KOK G., NASIBLI H., NOBAKHT R., PANMAN M., PAREDES X., RADICEVIC I., PÉREZ-SANZ F.J., PERSIJN S., ROJO A., ROSSO L., SAIRANEN H., SEGOVIA J.J., SÖDERBLOM H., SPARASCI F., STRNAD R., STRNADOVÁ L., TABANDEH S. and VAN DIJK M., “A European-wide measurement infrastructure for trace water in ultra-pure process gases”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

FERREUX E., STESHCHENKO T., SHAKESPEARE C., KOZLOVA O., BRIANT T., MARTEL T., BRAIVE R., GHORBEL I., GIGGIO L.A., COMBRIÉ S., DE ROSSI A., PITRE L., SPARASCI F. and BRIAUDEAU S., “Thermometry with optomechanical resonators from 4 K to 300 K”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

FLEURENCE N., DOURI S., GOMÈS S., DELVALLÉE A., HAMEURY J. and FELTIN N., “Study of self-heated resistive probe wear in scanning thermal microscopy (SThM)”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

GAMBETTE P., GAVIOSO R.M., SPARASCI F. and PITRE L., “Temperature control at 5.4 K for a cryogenic quantum pressure standard”, Poster, 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. and PITRE L., “Implementing new kelvin at temperatures below 25 K”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

GEORGIN E., CHEVALIER V. and TALLAWI B., “Traceability in trace moisture measurement: a mixed-flow humid air generator developped at LNE-CETIAT”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

GEORGIN E., FURTADO A., CHEVALIER V., VUILLAT F., ZENEBE F., SUBAS Ö. and SCHWINGHAMMER M., “Inter-Laboratory Comparison on Humidity Calibration: Collaboration Between LNE-CETIAT and PI GmbH”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

GUO W., ZHANG H., GAO B., TAUZIN C. and PITRE L., “Disseminating PLTS-2000 temperature below 1 K using a superconducting reference device”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

HAY B., BEAUMONT O. and HAMEURY J., “Improving SI-traceability of high temperature thermal diffusivity measurements for space applications”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

KNAZOVICKÁ L., BOURSON F., BOJKOVSKI J., BROBERG P., CLAUSEN S., GOZONUNDE C., HOLMSTEN M., KRÁLOVÁ M., MANUIR M.I., MLACNIK V., NÆSBY RASMUSSEN A., NASIBLI H., OPEL K., PAVLÁSEK P., SADLI M., ZUZEK V. and FALNES OLSEN A.A., “Extensive sharing of knowledge and experience in the field of high-temperature radiation thermometry”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

KONG X., LIU S., SONG Y., ZHANG H., GUO W., GAO B. and PITRE L., “Towards direct realisation of the ITS-90 in a primary gas thermometer between 2 K and 5 K”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

KOZLOVA O., BRAIVE R., BRIANT T., BRIAUDEAU S., DU G., EISERMANN R., FERREUX E., GAVIOSO R.M., IMBRAGUGLIO D., JORDAN J.E., KHOKHAR M., KRENEK S., MACHIN G., MARKO I., MARTEL T., MARTIN M.J., NORTE R.A., PITRE L., POURJAMAL S., QUEISSER M., REBOLLEDO I., SANCHEZ I., SCHMID D., SPARASCI F., STEENEKEN P.G., STESHCHENKO T., SWEENEY S.J., TABANDEH S., WINZER G., ZAMORA GÓMEZ A.V., ZELAN M. and ZIMMERMANN L., “Overview of EURAMET project: Photonic and Quantum Sensors for Practical Integrated Primary Thermometry (PhoQuS-T)”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

KOZLOVA O., BRAIVE R., T. BRIANT T., BRIAUDEAU S., CASAS A., CUPERTINO A., DICKMANN W., DU G., EISERMANN R., FERREUX E., HAHTELA O., GAVIOSO R.M., IMBRAGUGLIO D., JORDAN J.E., KRENEK S., KROKER S., LOUBAR F., MACHIN G., MARKO I., MARTEL T., MARTIN M.J., NORTE R.A., PITRE L., POSTIGO P.A., POURJAMAL S., QUEISSER M., RAMOS D., REBOLLEDO I., SANCHEZ I., SCHMID D., SHAKESPEARE C., SPARASCI F., STEENEKEN P.G., STESHCHENKO T., SWEENEY S., TABANDEH S., WINZER G., WEITUSCHAT L., ZAMORA GÓMEZ A.V., ZELAN M. and ZIMMERMANN L., “Towards practical integrated primary thermometry with photonic and quantum sensors in Europe”, 150th anniversary of the Metre Convention and the BIPM - Accepted Abstracts (poster online), 20 May 2025, https://thebipm150.org/posters-online/.

KRENEK S., EISERMANN R., FAILLEAU G., LU X., THOMAS P.J. and KJELDSEN H., “The INFOTherm project – Research and calibration infrastructure for fibre-optic thermometry”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

LAVERGNE T., RISEGARI L. and SPARASCI F., “Comparative study of CSPRTs and acoustic thermometry between 24 K and 300 K”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

LIU S.Q., KONG X.J., ZHANG H.Y., GAO B. and PITRE L., “Research on rapid temperature control methods in 2K to 5K thermodynamic temperature measurement device”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

MARTIN C., SPARASCI F., TRUONG D. and RISEGARI L., “Development of metallic fixed-point cells between Indium and Aluminium point at LNE-CNAM: expanding know-how for the dissemination of the new kelvin definition”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

MCEVOY H.C., LOWE D.H., MACHIN G., MARTIN M.J., MANTILLA J.M., ANHALT K., SADLI M., BOURSON F., LU X., YOO Y., YOON H., TODD A.D.W., SASAJIMA N. and YAMADA Y., “Outcome of the CCT comparison of ITS 90 realisations above the silver point”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

PANMAN M.R., DE BRUIN – BARENDREGT C., DOBRE M., VELTCHEVA R.I., PEARCE J., BUENGER L., ANHALT K., SPARASCI F., RISEGARI L. and MARTIN C., “An extensive direct zinc fixed-point cells comparison”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

PANT U., SPARASCI F., PLIMMER M.D. and PITRE L., “Progress on measurement of the T-T₉₀ Using Acoustic Gas Thermometry of helium -4 with a large-volume Quasi-Spherical Resonator”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

PITRE L., SPARASCI F. and TAUZIN C., “Toward a comparison between second sound thermometer against PLTS-2000 and ITS-90 from 2.13K down to 10 mK”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

PITRE L., TAUZIN C. and SPARASCI F., “Evaluating different methods in acoustic frequency measurement: advancing towards a practical AGT”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

PUSNIK I., MARTIN M.J., BOURSON F., SADLI M., MAC LOCHLAINN D., KNAZOVICKA L., ANHALT K. and MLACNIK V., “The need for a guide on radiation thermometry”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

RAZOUK R., BEAUMONT O., HAMEURY J. and HAY B., “Development of metrological reference facilities for specific heat measurements at high temperatures”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

SADLI M., BOURSON F., ROUGIÉ B., KOZLOVA O. and BRIAUDEAU S., “25 years of research on high-temperature fixed points and thermodynamic temperature measurements”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

SADLI M., FALNES OLSEN A.A., KNAZOVICKÁ L., PAVLÁSEK P., NASIBLI H., BOURSON F., BOJKOVSKI J., BROBERG P., CLAUSEN S., GÖZÖNÜNDE C., HOLMSTEN M., KADI O.F., KRÁLOVÁ M., KOZLOVA O., MANIUR M.I., MLACNIK V., NÆSBY RASMUSSEN A., OPEL K. and ŽUŽEK V., “MultiFixRad: a European project for the mise-en-pratique of the kelvin at high temperature using HTFPS”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

SINGH M., RISEGARI L., PAVLASEK P. and SPARASCI F., “Development of alternative fixed-point cells for low-temperature metrology: A replacement for the mercury triple point”, Poster, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

SONG Y.N., ZHANG H.Y., LIU S.Q., LI G.X., GAO B., LI F.H. and PITRE L., “Stability and calibration of Chinese platinum cobalt resistance thermometers from 4 K to 25 K”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

SPARASCI F., BÜNGER L., LOPARDO G., PANMAN M. and PEARCE J., “Realization of the key comparison Euramet.T-K9: a summary of the results”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

TABANDEH S., ARPINO F., BELL S., BELTRAMINO G., BENYON PUIG R., CARROLL P., CHIODO N., CORTELLESSA G., CUCCARO R., DELL’ISOLA M., ENESCU D., GARCIA GALLEGOS J., GEORGIN E., HUDOKLIN D., KOK G., NOBAKHT R., PANMAN M.R., PAREDES X., PEREZ SANZ F., PERSIJN S., ROJO A., ROSSO L., SEGOVIA J.J., SÖDERBLOM H., STEVANOVIC I., STRNAD R., STRNADOVÁ L., VAN DIJK M. and FERNICOLA V., “Novel functional equations for the water vapor enhancement factor in pure gases”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

TALLAWI B., GEORGIN E. and SABOUROUX P., “In-situ traceable measurement of moisture and water content with microwave technology”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

TAUZIN C., SPARASCI F., PLIMMER M.D. and PITRE L., “PLTS-2000 at LNE-CNAM”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

URBAN D., MUELLER I., GIRARD F., FLORIO M., NASIBLI H., GÖZÖNÜNDE C., MARTIN M.J., MANTILLA J.M., SADLI M., KOSMALSKI S., RONGIONE L., LU X., BUENGER L., ANHALT K., SCHWABENLAND M., HUTZSCHENREUTER D. and HAERTIG F., “Evaluation of key comparisons using the digital metrology expert tool (DME)”, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

ZHANG H.Y., SONG Y.N., KONG X.J., GAO B. and PITRE L., “Relative refractive-index gas thermometry and thermodynamic temperature wire scale from 5 K to 25 K”, Oral presentation, TEMPMEKO – ISHM 2025, Reims, France, 20-24 October 2025.

HAY B., BEAUMONT O., RAZOUK R., FLEURENCE N. and HAMEURY J., “SI-traceable thermal diffusivity measurements of advanced materials at ultra-high temperature”, IWSSTP2025 – 14th International Workshop on Sub-Second Thermophysics, Lorient, France, 24-26 June 2025.

RAZOUK R., BEAUMONT O., HAMEURY J. and HAY B., “LNE initiatives in the development of metrological reference facilities for specific heat measurements at high temperatures”, IWSSTP2025 – 14th International Workshop on Sub-Second Thermophysics, Lorient, France, 24-26 June 2025.

FLEURENCE N., DOURI S., DELVALLÉE A., CHIBANE L. and FELTIN N., “Thermal characterization at the micro- and nanoscale”, 8th NANOscientific Forum Europe (NSFE 2025), Orsay, France, 17-19 September 2025.

STESHCHENKO T., SHAKESPEARE C., CROQUETTE M., FERREU E., LOUBAR F., KOZLOVA O., SPARASCI F., PITRE L., MARTEL T., BRAIVE R., BRIANT T. and BRIAUDEAU S., “Quantum Thermometry with Optomechanics”, Poster, 10th Annual Meeting of the GdR MecaQ, Paris, France, 29-30 September 2025.

DOURI S., FLEURENCE N., GOMÈS S., DELVALLÉE A. and HAMEURY J., “Study of self-heated resistive probe wear in scanning thermal microscopy (SThM)”, Journées Plénières GDR NAME 2025, Palaiseau, France, 12-14 November 2025.

CHRISTENSEN J.B., JØRGENSEN A.A., VANDBORG M.H., THOMAS P.J., LU X., FAILLEAU G., EISERMANN R., GRÜNER-NIELSEN L., BALSLEV-HARDER D., LASSEN M. and KRENEK S., “Fiber-artefact methodology and calibration framework for Brillouin-based fiber sensing”, Opt. Express, 2024, 32, 26, DOI: 10.1364/OE.544659.

DEDYULIN S., PERUZZI A., DEL CAMPO D., IZQUIERDO B.C.G., GOMEZ M.E., QUELHAS K.N., NETO M.A.P., LOZANO B.M., EUSEBIO L., YANG I., SPARASCI F., MARTIN C., RISEGARI L., SAUNDERS P., MOLLOY E., YAN X.K., SUN J.P., FENG X.J., ZHANG J.T., HO M.-., NAKANO T., WIDIATMO J.V., SAITO I., EJIGU E., PEARCE J., RUSBY R., RUDTSCH S., BUENGER L., KALEMCI M., UYTUN A., BRUIN-BARENDREGT C., PANMAN M., VAN GEEL J., WHITE D.R. and POSSOLO A., “From CCT-K7 to CCT-K7.2021: Approaching the definition of the triple point of water temperature”, AIP Conference Proceedings, 2024, 3230, 1, DOI: 10.1063/5.0234488.

DURBIANO F., MORITZ L., LEITO I., TALLAWI B., KLAHN E.A., ISLEYEN A., POPOV A., PETRENKO A., KOLESNIKOVA T. and PÁLKOVÁ Z., “Presentation of the new EPM 23RPT03 project “Metrology for standardised moisture/water content measurement in plant-origin bulk materials in support of International and European food safety and trade – GrainMet”, Measurement: Sensors, 2024, DOI: 10.1016/j.measen.2024.101521.

GUIANVARC’H C., FAVIER E., LAVERGNE T. and RISEGARI L., “Vibration of microphone membrane: Effects of thermal stress”, Journal of Sound and Vibration, 2024, 588, DOI: 10.1016/j.jsv.2024.118518.

IMBRAGUGLIO D., PAN C., SPARASCI F., GAVIOSO R.M., RIPA D.M., ROURKE P.M.C., ZHANG H., GAO B. and PITRE L., “From ITS-90 to thermodynamic temperature: Hybrid CSPRT calibrations with LNE-Cnam acoustic gas thermometry”, AIP Conference Proceedings, 2024, 3230, 1, DOI: 10.1063/5.0236619.

KIRSTE A., ENGERT J., PEKOLA J., PELTONEN J., TABANDEH S., PITRE L. and SPARASCI F., “Realizing the redefined Kelvin: Realization and dissemination of the Kelvin below 25 K”, AIP Conference Proceedings, 2024, 3230, 1, DOI: 10.1063/5.0234869.

KJELDSEN H., ØSTERGAARD P.F., STRAUSS H., NIELSEN J., TALLAWI B., GEORGIN E., SABOUROUX P., NIELSEN J.G. and HOUGAARD J.O., “Calibration Techniques for Water Content Measurements in Solid Biofuels”, Energies, 2024, 17, 3, DOI: 10.3390/en17030635.

KOWAL A., SPARASCI F., PAN C., TAUZIN C., ZHANG H., GAO B. and PITRE L., “The direct comparison of 3He and 4He vapor-pressure thermometers at LNE-Cnam within their overlapping temperature range”, AIP Conference Proceedings, 2024, 3230, 1, DOI: 10.1063/5.0234151.

LOWE D., BOURSON F., FLORIO M., GIRARD F., MACHIN G., MANTILLA J., MARTIN M.J., NASIBLI H., PEHLIVAN O. and SADLI M., “High-temperature fixed-point furnace uncertainties”, AIP Conference Proceedings, 2024, 3230, 1, DOI: 10.1063/5.0234816.

MACHIN G., SADLI M., ENGERT J., KIRSTE A., PEARCE J. and GAVIOSO R.M., “Progress with realizing the redefined Kelvin”, AIP Conference Proceedings, 2024, 3230, 1, DOI: 10.1063/5.0234456.

MCEVOY H., LOWE D., MACHIN G., JOSÉ MARTIN M., ANHALT K., HOLLANDT J., SADLI M., BOURSON F., YAMADA Y., SASAJIMA N., LU X., YOO Y., YOON H., GIBSON C., TODD A. and WOODS D., “Final report for CCT comparison of ITS-90 realisations above the silver point using two transfer radiation thermometers and a set of high temperature fixed-point blackbody cells”, Metrologia, 2024, 61, 1A, DOI: 10.1088/0026-1394/61/1A/03003.

PAVLASEK P., RISEGARI L. and SPARASCI F., “Manufacturing and realization of the low volume fixed-point of sulfur hexafluoride (SF6)”, AIP Conference Proceedings, 2024, 3230, 1, DOI: 10.1063/5.0236046.

PEARCE J.V., RUSBY R.L., VELTCHEVA R.I., DEL CAMPO D., IZQUIERDO C.G., MERLONE A., COPPA G., KOWAL A., EUSEBIO L., BOJKOVSKI J., ŽUŽEK V., SPARASCI F., PAVLASEK P., KALEMCI M., UYTUN A. and PERUZZI A., “Realizing the redefined Kelvin: Extending the life of ITS-90”, AIP Conference Proceedings, 2024, 3230, 1, DOI: 10.1063/5.0234458.

SADLI M., BOURSON F., LOWE D., ANHALT K., TAUBERT D., MARTIN M.J., MANTILLA J.M., GIRARD F., FLORIO M., GÖZÖNÜNDE C., NASIBLI H., KNAZOVICKÁ L., SASAJIMA N., LU X., KOZLOVA O., BRIAUDEAU S. and MACHIN G., “Thermodynamic temperatures of Fe-C, Pd-C, Ru-C and WC-C for the Mise-en-Pratique of the Kelvin up to 3020 K”, AIP Conference Proceedings, 2024, 3230, 1, DOI: 10.1063/5.0234550.

SADLI M., KŇAZOVICKÁ L., PAVLÁSEK P., NASIBLI H., BOURSON F. and FALNES OLSEN Å.A., “New capabilities for the realisation and the dissemination of the kelvin at high temperature in Europe”, Measurement: Sensors, 2024, DOI: 10.1016/j.measen.2024.101624.

SPARASCI F., RISEGARI L., MARTIN C., HERMIER Y., LOPARDO G., STEUR P.P.M., PEARCE J., BÜNGER L., RUDTSCH S., BRUIN-BARENDREGT C.D., PANMAN M., PERUZZI A., HOFSTÄTTER-MOHLER C., TURZÓ-ANDRÁS E., NEDIALKOV S., SPASOVA S., PETRUSOVA O., JOSÉ MARTÍN HERNANDEZ M., MALDONADO D.D.C., GARCÍA IZQUIERDO C., STRNAD R., SIMIC S., STEPANOVIC V., NIELSEN J., KOKKINI E., GAIDAMOVICIUTE L., GALKAUSKAS L., MIKALAUSKAS K., KOZICKI M., ZVIZDIC D., ŠESTAN D., MUTAPCIC N., STRATULAT C., NEAGU M.D., EUSÉBIO L., OLSEN Å.A.F., BERGERUD R.A., OPEL K., KVERNMO G., HÖGSTRÖM R., HEINONEN M., BOJKOVSKI J., ŽUŽEK V., MACLOCHLAINN D., HOLMSTEN M., SENN R., DOBRE M., PAVLASEK P. and KALEMCI M., “EURAMET.T-K9 regional key comparison ITS-90 SPRT calibration from the Ar TP to the Zn FP”, Metrologia, 2024, 61, 1A, DOI: 10.1088/0026-1394/61/1A/03005.

ZHANG H., SONG Y., KONG X., GAO B., PLIMMER M. and PITRE L., “Repeatability of a primary thermometer and calibration of resistance thermometers between 5 K and 25 K”, Metrologia, 2025, 62, 1, DOI: 10.1088/1681-7575/ad87f5.

PITRE L., « Métrologie des basses températures », Action Nationale de Formation "Détection de rayonnements à très basse température" (DRTBT2024), Centre CAES Paul-Langevin, Aussois, France, 24-27 March 2024.

SADLI M., KNAZOVICKÁ L., PAVLASEK P., NASIBLI H., BOURSON F. and OLSEN Å.A.F., « Projet MultiFixRad : Développement de nouvelles capacités de recherche pour la réalisation et la dissémination du kelvin à haute température en Europe », CAFMET 2024 - 9^e Conférence Internationale de Métrologie, Marrakesh, Morocco, 22-24 April 2024.

SONG Y., LIU S., ZHANG H., GAO B., LI F. and PITRE L., “Stability of standard platinum cobalt resistance thermometers under hundred low temperature cycling”, Journal of Harbin Institute of Technology, 2024, 56, 6, DOI: 10.11918/202301055.

RAMALINGAM A., SADLI M., KNAZOVICKÁ L., PAVLÁSEK P., NASIBLI H., BOURSON F. and OLSEN Å.A.F., “New capabilities for the realisation and the dissemination of the kelvin at high temperature in Europe”, IMEKO 2024 - XXIV World Congress, Hamburg, Germany, 26-29 August 2024.

TALLAWI B. and GEORGIN E., « Mesure de l’humidité dans les solides », Mesures Solutions Expo, Lyon, France, 16-17 October 2024.

FERREUX E., KOZLOVA O., STESHCHENKO T., LOUBAR F., MARTEL T., GHORBEL I., AIMONE-GIGGIO L., COMBRIÉ S., DE ROSSI A., BRAIVE R., BRIANT T. and BRIAUDEAU S., « Towards quantum thermometry using optomechanics », Journées de la Matière Condensée, Marseille, France, 28-31 October 2024.

CROQUETTE M., DELEGLISE S., KAWASAKI T., KOMORI K., KURIBAYASHI M., LARTAUX-VOLLARD A., MATSUMOTO N., MICHIMURA Y., ANDIA M., ARITOMI N., BRAIVE R., BRIANT T., BRIAUDEAU S.,  CATAÑO-LOPEZ S.B., CHUA S., DEGALLAIX J., FUJIMOTO M., GERASHCHENKO K., GLOTIN F.,  GRUNING P., HARADA K., HEIDMANN A., HOFMAN D., JACQUET P.-E., JACQMIN T., KOZLOVA O.,  LEROY N., LORIETTE V., LOUBAR F., MARTEL T., METZDORFF R., MICHEL C., MIKAMI A.,  NAJERA L., NEUHAUS L., OTABE S., PINARD L., SUZUKI K., TAKAHASHI H., TAKEDA K.,  TOMINAGA Y., VAN DE WALLEA, YAMAMOTO N., SOMIYA K. et COHADON P.-F., "Recent advances toward mesoscopic quantum optomechanics", AVS Quantum Sci., 2023, 5, DOI: 10.1116/5.0128487.

FLEURENCE N., DEMEYER S., ALLARD A., DOURI S. et HAY B., "Quantitative measurement of thermal conductivity by SThM technique: Measurements, calibration protocols and uncertainty evaluation", Nanomaterials, 2023, 13, DOI: 10.3390/nano13172424.

GARBEROGLIO G. , GAISER C., GAVIOSO R.M., HARVEY A.H., HELLMANN R., JEZIORSKI B., MEIER K., MOLDOVER M;R., PITRE L., SZALEWICZ K. et UNDERWOOD R., "Ab initio calculation of fluid properties for precision metrology", J. Phys. Chem. Ref. Data, 2023, 52, DOI: 10.1063/5.0156293.

GOMES S., BOURGEOIS O., FLEURENCE N., DILHAIRE S., BRAIVE R. et GRAUBY S., « Micro & Nano-thermique - Méthodes de caractérisation et de mesure », Techniques de l’ingénieur, 2023, R6801 V1, DOI: 10.51257/a-v1-r6801.

HAY B., BEAUMONT O., FLEURENCE N., LAMBENG N., CATALDI M., LORRETTE C.,  KNOPP K., HARTMANN J., BECKSTEIN F., STOBITZER D., MILOSEVIC N.,  STEPANIC N., WU J. et MILDEOVA P., "Inter‑laboratory comparison on thermal diffusivity measurements by the laser flash method at ultra‑high temperature", Int J Thermophys, 2023, 44, 48, DOI: 10.1007/s10765-023-03159-5.

HERMAN T., CHOJNACKY M., HILL K., RUDTSCH S., YANG I., STEUR P.P.M., DEMATTEIS R., LOPARDO G., SPARASCI F., MARTIN C., RISEGARI L., WIDIATMO J., NAKANO T., SAITO I., QUELHAS K.N., GIORGIO P., SUN J., ZHANG J., PEARCE J. et GRAY J., "KEY COMPARISON - ITS-90 SPRT calibration from the Ar TP to the Zn FP", Metrologia, 60, 2023, DOI: 10.1088/0026-1394/60/1A/03001.

PERUZZI A., DEDYULIN S., LEVESQUE M., DEL CAMPO D., GARCIA IZQUIERDO G.C., GOMEZ M.E., QUELHAS K.N., NETO M.A.P., LOZANO B.M. et EUSEBIO L., "CCT-K7.2021: CIPM key comparison of water-triple-point cells", Metrologia, 2023, 60, DOI: 10.1088/0026-1394/60/1A/03002.

HAY B., "Assessment of uncertainty associated with very high temperature thermal diffusivity measurements", 21^e congrès international de Métrologie (CIM 2023), Lyon, France, 7-10 mars 2023.

SADLI M., "Assigning thermodynamic temperatures to a set high-temperature fixed points in the range 1400 K to 3000 K", 21^e congrès international de Métrologie (CIM 2023), Lyon, France, 7-10 mars 2023.

BOURSON F., "New high-temperature references for industrial applications", 21^e congrès international de Métrologie (CIM 2023), Lyon, France, 7-10 mars 2023.

DOURI S., "Scanning thermal microscopy modeling by 3D FEM in vacuum and in air conditions", 21^e congrès international de Métrologie (CIM 2023), Lyon, France, 7-10 mars 2023.

DEDYULIN S., PERUZZI A., DEL CAMPO D., GARCIA IZQUIERDO B.C., GOMEZ M.E., QUELHAS K.N.,  NETO M.A.P., LOZANO B.M., EUSEBIO L., YANG I., SPARASCI F., MARTIN C., RISEGARI L., SAUNDERS P., MOLLOY E., YAN X.K., SUN J.P., FENG  X.J., ZHANG J.T., HO M.-K.,  NAKANO T., WIDIATMO J.V., SAITO I., EJIGU E., PEARCE J., RUDTSCH S., BUENGER L., KALEMCI M.,  UYTUN A., BRUIN-BARENDREGT C., PANMAN M., WHITE D.R. et POSSOLO A., "From CCT-K7 to CCT-K7.2021: approaching the definition of the triple point of water temperature", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

GAO B., ZHANG H., KONG X., SONG Y., LUO E. et PITRE L., "New T-T90 data from 5K to 24.5 K by single-pressure refractive-index gas thermometry", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

IMBRAGUGLIO D., PAN C., SPARASCI F., GAVIOSO R., MADONNA RIPA D., ROURKE P.M.C.,  ZHANG H., GAO B. et PITRE L., "From ITS-90 to Thermodynamic Temperature: Hybrid SPRT Calibrations with LNECnam Acoustic Gas Thermometry", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

KIRSTE A., ENGERT J., PEKOLA J., PELTONEN J., TABANDEH S., PITRE L. et SPARASCI F., "Realising the redefined kelvin: Realisation and dissemination of the kelvin below 25 K", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

KOWAL A., SPARASCI F., PAN C., TAUZIN C., ZHANG H., GAO B. et PITRE L., "Direct comparison of 3He and 4He vapor-pressure thermometers at LNE-Cnam within their overlapping temperature range", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

LOWE D., MACHIN G., MANTILLA J., MARTIN M.J., GIRARD F., FLORIO M., SADLI M., BOURSON F., NASIBLI H. et PEHLIVAN O., "High-Temperature fixed-point furnace uncertainty", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

MACHIN G., SADLI M., ENGERT J., KIRSTE A., PEARCE J. et GAVIOSO R., "Progress with realizing the redefined kelvin", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

PAVLASEK P., RISEGARI L. ET SPARASCI F., "Capsule and Long stem SPRT calibration by low volume fixed point of Sulfur Hexafluoride (SF6)", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

PEARCE J.V., RUSBY R.L., VELTCHEVA R.I., DEL CAMPO D., GARCIA IZQUIERDO C., MERLONE A., COPPA G., KOWAL A., EUSEBIO L., BOJKOVSKI J., ŽUZEK V., SPARASCI F., PAVLASEK P., KALEMCI M., UYTUN A. et PERUZZI A., "Realizing the redefined kelvin: Extending the life of the ITS-90", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

SADLI M., BOURSON F., LOWE D., ANHALT K., TAUBERT D., MARTIN M.J., MANTILLA J.M., GIRARD F., FLORIO M., GÖZÖNÜNDE C., NASIBLI H., KNAZOVICKA L., SASAJIMA N., LU X., KOZLOVA O., BRIAUDEAU S. et MACHIN G., "Realizing the redefined kelvin: thermodynamic temperatures of Fe-C, Pd-C, Ru-C and WC-C for the mise-en-pratique of the kelvin up to 3020 K", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

SADLI M., PITRE L., BRIAUDEAU S., BOURSON F. et SPARASCI F., "Relative thermodynamic temperature over the whole temperature range", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

SONG Y., KONG X., ZHANG H., GAO B., SPARASCI F., LUO E. et PITRE L., "Establishing and maintaining the ITS-90 Wire scale at CAS using Rhodium-Iron resistance thermometers from 5K to 24.5K", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

ROURKE P.M.C., GAISER C., GAVIOSO R.M., KAWAMURA Y., MACHIN G., MÜLLER I., SADLI M., SAUNDERS P., YANG I. et ZHANG J., "The CCT Task Group on digitalization", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

TAUZIN C., SPARACI F., PLIMMER M.D. et PITRE L., "Thermometry below 1 K, a comparison of several reference sensors based on different physics principles at LNE-Cnam", Tenth International Temperature Symposium, Anaheim, CA USA, 3-7 avril 2023.

Moisture content measurements in solid materials, as accurate and traceable to the SI, is a technical and scientific challenge. The difficulty comes from the great diversity of measurands, resulting from extremely varied measurement techniques. This is reinforced by the variability of the physical and chemical properties of materials in the presence of the water molecule. Thus materials can be affected through their chemical composition, structure, texture, mechanical properties and thermal properties.

The duration of the analysis, the size of the sample, the complexity of the solid materials, and the requirement for laboratory conditions are occasionally limitations of traditional techniques for measuring moisture, which are classified as the primary techniques from a metrological view. Nevertheless, these methods also have the best accuracy and lowest uncertainties. To allow a better dissemination of metrological traceability, and to overcome some limitations of reference methods, alternative measurement methods are needed. They aim to improve on-site moisture measurement or to allow calibration of devices already installed on industrial processes, all in a relatively short time and in a potentially restrictive environment: Temperature, vibration, fouling, and electromagnetic perturbations.

Among the solutions identified, there are several methods, falling into the category of secondary methods, such as electromagnetic spectroscopy, infrared measurement, electron microscopy and thermography. These methods are promising for determining the moisture content of solids, but often their measurement principles lead to measurements different from those of primary methods. Although, they allow characterizing the physical and chemical properties of the materials and can be used to determine their humidity, subject to performing a calibration against one of the primary techniques to ensure SI traceability.

The first part of the work was to validate a coaxial measuring cell, developed at LNE-CETIAT, for the measurement of dielectric permittivity. This validation was carried out by comparison with the EpsiMu® tool, the open-ended coaxial probe using reference materials identified in the literature. Furthermore, a cylindrical resonant cavity that serves as a transfer device was developed and characterized. This industrial equipment has notably been studied with reference materials and wood derivatives. The cavity allows the measurement of the dielectric properties of the materials, taking care however to proceed to the identification of certain characteristic parameters, by using the coaxial cell.

The second part focused on the investigation, improvement, and development of experimental procedures related to the implementation of reference methods. The loss on drying method and two electrolytic techniques including the coulometric Karl Fischer titration and the electrolysis of phosphoric acid produced when water vapor and 9 phosphoric pentoxide are combined were discussed. The measurement methods as well as the uncertainty balances were validated through intra and inter-laboratory comparisons.

Finally, by combining the electromagnetic characterization of the resonant cavity and one of the primary methods, calibration curves could be established between the measured dielectric quantities and the moisture content of the materials. As a result, the developed device enables quick analysis times and non-destructive measurements of the moisture in solids. The demonstration of its application could be done at an industrial site to calibrate an instrument measuring the moisture of pellets and wood chips.

traceability, moisture content, metrology, microwave, permittivity, solids.

Full document (FR) : HAL-04302278

In 2018, the 26th General Conference on Weights and Measures (CGPM) redefined the various units of the International System (SI), in particular the kelvin, the unit of temperature, which is now based on the fixed value of the Boltzmann constant kB. This redefinition spurred the development of new primary temperature sensors to disseminate the new Kelvin. Sensors based on quantum technologies are very popular in the metrology community.

In this context, we propose a multimodal temperature sensor whose operation is based on the optical and optomechanical properties of a 1D photonic crystal. Indeed, under the effect of temperature, the resonator sees its optical resonance frequency shift, and the Brownian motion induced by the surrounding thermal bath changes. These two effects allow the temperature of the resonator to be determined in two different ways, provided that the calibration is correct. This type of optomechanical resonator opens the way to self-calibrating primary temperature sensors with quantum correlations resulting from the radiation pressure force exerted by light.

optomechanics, temperature sensor, photonic crystal, phononic crystal, quantum correlation.

Full document (EN) : HAL-04047507

 This thesis describes the development of an acoustic thermometry apparatus to estimate the mean temperature along an optical measurement path and thereby better determine the air refractive index. The measurement principle uses the time-of-flight (TOF) of an ultrasonic wave at 40 kHz. The temperature is extracted from the speed of sound using the Cramer equation which gives acoustic velocity as a function of atmospheric parameters (temperature, pression, humidity and CO2 concentration). Different methods for estimating the TOF were studied for six types of signal (single-frequency or modulated, top-hat, Gaussian and Blackman envelopes), notably intercorrelation, and a calibration procedure with respect to reference thermometers placed at intervals along the path developed. The temperature uncertainty achieved for a 10 m distance is 90 mK.

Thermometry, Acoustics, Metrology, Cross-correlation, Ultrasonics, Refractive index

PhD thesis (French) : https://theses.hal.science/tel-03997959v1/document

BRIANT T., KRENEK S., CUPERTINO A., LOUBAR F., BRAIVE R., WEITUSCHAT L., RAMOS D., MARTIN M.J., POSTIGO P.A., CASAS A., EISERMANN R., SCHMID D., TABANDEH S., HAHTELA O., POURJAMAL S., KOZLOVA O., KROKER S., DICKMANN W., ZIMMERMANN L., WINZER G., MARTEL T., STEENEKEN P.G., NORTE R.A. and BRIAUDEAU S., “Photonic and Optomechanical Thermometry”, Optics, 2022, 3, 2, DOI: 10.3390/opt3020017. 

GAISER C., FELLMUTH B., GAVIOSO R.M., KALEMCI M., KYTIN V., NAKANO T., POKHODUN A., ROURKE P.M.C., RUSBY R., SPARASCI F., STEUR P.P.M, TEW W.L., UNDERWOOD R., WHITE R., YANG I. and ZHANG J., “2022 Update for the Differences Between Thermodynamic Temperature and ITS-90 Below 335 K”, J. Phys. Chem. Ref. Data, 2022, 51, DOI: 10.1063/5.0131026.

HU J., ZHANG H., SONG Y., PAN C., GAO B., LIU W., HAN D., ZHANG Z., LUO E. and PITRE L., “Investigation of High-Stability Temperature Control in Primary Gas Thermometry”, Journal of Thermal Science, 2022, 31, DOI: 10.1007/s11630-022-1533-9.

MACHIN G., SADLI M., PEARCE J., ENGERT J. and GAVIOSO R.M., “Towards realising the redefined kelvin”, Measurement, 2022, 201, DOI: 10.1016/j.measurement.2022.111725.

SADLI M., GEORGIN E. and al., « Mesures de température - Bonnes pratiques et applications dans l'industrie », Afnor, Les guides techniques du Collège français de métrologie, 2022, ISBN: 978-2-12-465794-0.

SALIM S.G.R., “Thermal conductivity measurements using the transient hot-wire method: a review”, Measurement Sci. Technol., 2022, 33, DOI: 10.1088/1361-6501/ac90df.

SPARMA F., TALLAWI B., GEORGIN E. and SABOUROUX P., “Multi-Probe Sensor for Water Content Diagnosis of Liquid Biofuels”, Progress In Electromagnetics Research Letters, 2022, 106, DOI: 10.2528/PIERL22021104.

MACHIN G., SADLI M., PEARCE J., ENGERT J. and GAVIOSO R.M., “Towards realising the redefined kelvin”, SSRN Electronic Journal, DOI: 10.2139/ssrn.4108861, January 2022.

DOURI S., FLEURENCE N., HAMEURY J. and GOMES S., “SThM probe thermal response by two different models”, Forum des microscopistes, Saint-Valery-Sur-Somme, France, 7-13 March 2022.

FLEURENCE N., DELVALLÉE A., DOURI S., HAMEURY J. and FELTIN N., “Traceability of thermal conductivity measurements by SThM technique to characterize nanowires”, Forum des microscopistes, Saint-Valery-Sur-Somme, France, poster, 7-13 March 2022.

DOURI S., FLEURENCE N., HAMEURY J. and GOMES S., “SThM probe thermal response by 3D FEM”, Ecole d’été MONACOSTE: Modeling Nanomaterials for Energy Transport and Storage, Fréjus, France, poster, 8-13 May 2022.

DELVALLEE A., CHIBANE L., FLEURENCE N., FLAHAUT E. and FELTIN N., “Correlative imaging of single graphene oxide flake including Raman microscopy technique: sample selection and limitations”, Ramanfest, Paris, France, poster, 15-16 September 2022.

SADLI M., “Implementation and dissemination of the redefined kelvin”, CAFMET 2022, Casablanca, Maroc, 16-19 May 2022.

DOURI S., FLEURENCE N., HAMEURY J. and GOMES S., "SThM probe thermal response by 3D FEM", Nanoscale and Microscale Heat Transfer VII, Palerme, Italie, poster, 29 mai - 2 June 2022.

FLEURENCE N., DOURI S., HAMEURY J. and FELTIN N., “Assessment of uncertainties in thermal conductivity measurements by SThM technique”, Nanoscale and Microscale Heat Transfer VII, Palerme, Italie, Poster, 29 May - 2 June 2022.

RAZOUK R., BEAUMONT O., HAMEURY J. and HAY B., « Vers la mise en place de références métrologiques en capacité thermique massique par calorimétrie à chute jusqu’à 3000 °C », SFT, 30e Congrès Français de Thermique, DOI : 10.25855/SFT2022-073, Valenciennes, France, poster, 31 May - 3 June 2022.

GEORGIN E., "Reference techniques implemented at LNE-CETIAT", 1st BIOFMET Stakeholders' Workshop, Lisbonne, Portugal, 2-3 June 2022.

TALLAWI B. and SABOUROUX P., "Transfer standard developed at LNE-CETIAT", 1st BIOFMET Stakeholders' Workshop, Lisbonne, Portugal, 2-3 June 2022.

E. FERREUX and al., “Optomechanical devices for fundamental measurements”, Les Houches School of Physics: Summer School “The New Mecanics”, Les Houches, France, Poster, 1-26 August 2022.

GOMES S., DILHAIRE S., FLEURENCE N., HORNY N., CHAPUIS P.-O., GRAUBY S., RAMPNOUX J.-M., PERNOT G., BONDAVALLI P., DOURI S., SOMMET R., CARISETTI D. and CHANEAC C., "Why is heat transport modelling required for nanometrology?", Société française de thermique, Journée thématique "Beyond Fourier", Paris, France, 9 September 2022.

HAY B., BEAUMONT O., RAZOUK R., FAILLEAU G. and HAMEURY J., “Recent developments at LNE in thermophysical properties metrology of solids at ultra-high temperatures”, 13th Asian Thermophysical Properties Conference (ATPC 2022), Sendai, Japon, 26-30 September 2022.

FERREUX E., LOUBAR F., KOZLOVA O., BRAIVE R., BRIANT T. and BRIAUDEAU S., “Quantum Thermometry using an optomechanical crystal”, GdR MecaQ, 7th Annual Meeting, Bordeaux, France, 6-7 October 2022.

KOZLOVA O. and al., “Quantum Thermometry using Optomecanics”, DIM QuanTiP kick-off, Villetaneuse, France, poster, 10 November 2022.

The work concerns the development of a novel absolute gas pressure standard in a range of 200 Pa to 20 kPa (0.002 atm to 0.2 atm). The method used, refractive index gas manometry, involves the determination of the refractive index of a pure noble gas (helium-4 or argon) using a microwave resonator. The refractive index is determined via the ratio of the resonant frequencies measured with the resonator under vacuum and under pressure at a constant temperature. Given the thermodynamic temperature of the gas and its refractive index, it is possible to calculate its pressure. This principle is the reciprocal of that used for refractive index gas thermometry (RIGT) in which thermodynamic temperature is extracted from the measured refractive index of gas at a known pressure. The frequency scanning pattern and fitting algorithms take advantage of earlier work in the laboratory on the determination of the Boltzmann constant prior to the 2019 redefinition of the kelvin, the SI unit of thermodynamic temperature. For Helium-4, measurements were made at 5.4 K using a quasi-spherical copper resonator coated on its inner surface with a 3 μm thick layer of superconducting niobium. Superconductivity improves the quality factor Q of the resonator and thereby the frequency resolution of the system. The pressure determination benefits from the very high accuracy of the dielectric and density virial coefficients of helium-4 obtained by ab initio calculations. Measurements on Argon were performed at a temperature of 90.4 K with an uncoated copper resonator. At this temperature, the apparatus is less demanding in terms of cryogenics than its helium counterpart and so easier to replicate.

ab initio calculation, pressure standard, metrology, manometry, thermometry, microwave cavity, superconductivity, refractive index, virial coefficient, helium, argon

PhD Thesis (EN) : https://tel.archives-ouvertes.fr/tel-03652344