Photonic contact thermometry using silicon ring resonators and tuneable laser-based spectroscopy

Photonic sensors offer the possibility of purely optical measurement in contact thermometry. In this work, silicon-based ring resonators were used for this purpose. These can be manufactured with a high degree of reproducibility and uniformity due to the established semiconductor manufacturing process. For the precise characterisation of these photonic sensors, a measurement setup was developed which allows laser-based spectroscopy around 1550 nm and stable temperature control from 5 °C to 95 °C. This was characterised in detail and the resulting uncertainty influences of both the measuring set-up and the data processing were quantified. The determined temperature stability at 20 °C is better than 0.51 mK for the typical acquisition time of 10 s for a 100 nm spectrum. For a measurement of >24 h at 30 °C a standard deviation of 2.6 mK could be achieved. A hydrogen cyanide reference gas cell was used for traceable in-situ correction of the wavelength. The determined correction function has a typical uncertainty of 0.6 pm. The resonance peaks of the ring resonators showed a high optical quality of 157 000 in the average with a filter depth of up to 20 dB in the wavelength range from 1525 nm to 1565 nm. When comparing different methods for the determination of the central wavelength of the resonance peaks, an uncertainty of 0.3 pm could be identified. A temperature-dependent shift of the resonance peaks of approx. 72 pm/K was determined. This temperature sensitivity leads together with the analysed uncertainty contributions to a repeatability of better than 10 mK in the analysed temperature range from 10 °C to 90 °C.Photonische Sensoren bieten die Möglichkeiten einer rein optischen Messung in der Berührungsthermometrie. In dieser Arbeit wurden hierfür siliziumbasierte Ringresonatoren verwendet. Diese lassen sich aufgrund der etablierten Halbleiterfertigung mit hoher Reproduzierbarkeit und Uniformität herstellen. Zur genauen Charakterisierung dieser photonischen Sensoren wurde ein Messplatz entwickelt, welcher eine laser-basierte Spektroskopie um 1550 nm und Thermostatisierung von 5 °C bis 95 °C ermöglicht. Dieser wurde ausführlich charakterisiert und resultierende Unsicherheitseinflüsse sowohl des Messplatzes als auch der Datenverarbeitung quantifiziert. Die ermittelte Temperatur-stabilitäten bei 20 °C ist besser als 0,51 mK für die typische Aufnahmezeit von 10 s eines 100 nm Spektrums. Für eine Messung von >24 h konnte bei 30 °C ein Standardabweichung von 2,6 mK erreicht werden. Eine Cyanwasserstoff-Referenzgaszelle diente zur rückführbaren in-situ Korrektur der Wellenlänge. Die ermittelte Korrekturfunktion hat hierbei typischerweise eine Unsicherheit von 0,6 pm. Die Resonanzpeaks der Ringresonatoren zeigten im Durschitt eine hohe optische Güte von 157 000 mit einer Filtertiefe von bis zu 20 dB im Wellenlängenbereich von 1525 nm bis 1565 nm. Beim Vergleich verschiedener Methoden zur Bestimmung der zentralen Wellenlänge der Resonanzpeaks konnte eine Unsicherheit von 0,3 pm ermittelt werden. Es wurde eine temperaturabhängige Verschiebung der Resonanzpeaks von ca. 72 pm/K bestimmt. Diese Temperatursensitivität führt mit den analysierten Unsicherheitsbeiträgen zu einer Wiederholbarkeit von besser als 10 mK im untersuchten Temperaturbereich von 10 °C bis 90 °C

Photonic and Optomechanical Thermometry

Temperature is one of the most relevant physical quantities that affects almost all processes in nature. However, the realization of accurate temperature standards using current temperature references, like the triple point of water, is difficult due to the requirements on material purity and stability of the environment. In addition, in harsh environments, current temperature sensors with electrical readout, like platinum resistors, are difficult to implement, urging the development of optical temperature sensors. In 2018, the European consortium Photoquant, consisting of metrological institutes and academic partners, started investigating new temperature standards for self-calibrated, embedded optomechanical sensor applications, as well as optimised high resolution and high re- liability photonic sensors, to measure temperature at the nano and meso-scales and as a possible replacement for the standard platinum resistant thermometers. This article presents an overview of the results obtained with sensor prototypes that exploit photonic and optomechanical techniques for sensing temperatures over a large temperature range (5 K to 300 K). Different concepts are demon- strated, including ring resonators, ladder-like resonators and suspended membrane optomechanical thermometers, highlighting initial performance and challenges, like self-heating that need to be overcome to realize photonic and optomechanical thermometry applications.This work was carried out under the 17FUN05 PhotOQuanT project, which has received funding from the EMPIR program, co-financed by the Participating States and the European Union’s Horizon 2020 research and innovation progra

The First Provenance Challenge

The first Provenance Challenge was set up in order to provide a forum for the community to help understand the capabilities of different provenance systems and the expressiveness of their provenance representations. To this end, a Functional Magnetic Resonance Imaging workflow was defined, which participants had to either simulate or run in order to produce some provenance representation, from which a set of identified queries had to be implemented and executed. Sixteen teams responded to the challenge, and submitted their inputs. In this paper, we present the challenge workflow and queries, and summarise the participants contributions

Traceability improvement of high temperature thermal property measurements of materials for new fission reactors

Generation IV nuclear reactors are one of the solutions that could best meet the goals of sustainable, safe, and competitive energy production. As their operating temperatures are much higher than those of both current pressurized and boiling water reactors, the choice of materials is even more of a key issue for the design and construction of these new fission reactor concepts. The thermal properties of the used materials can be indeed affected by neutron irradiation at high temperature. It is therefore fundamental to dispose of reliable data on the thermal behaviour of the materials in normal and off-normal operating conditions in order to check if they fulfil the requirements in terms of temperature and lifetime. Thermal characterizations of irradiated materials and nuclear fuels, that must be carried out under safe manipulation conditions, are performed up to very high temperatures by nuclear research institutes with some dedicated facilities. These institutes need reference materials certified at least up to 2000 °C, in order to calibrate the devices that they use to measure thermophysical properties. Three National Metrology Institutes (LNE, PTB, and NPL) and the Institute for Transuranium Elements (JRC-ITU) collaborate on a study aiming in particular to extend to very high temperature the measurement capabilities of their reference metrological facilities devoted to thermophysical property measurements. Two complementary facilities based on different metrological approaches for the measurement of normal spectral emissivity up to 1500 °C, and a very high temperature diffusivimeter have been notably developed. Methods and calorimeters for the measurement of specific heat up to 1500 °C have been also improved. These facilities will enable to perform accurate measurements, directly traceable to the International System of Units, at temperatures close to those encountered in real situations. They have been applied to the measurements of thermophysical properties at high temperature of well known materials (graphite and tungsten) and of materials that could potentially serve as “transfer reference materials” (MgO, Ni, and ZrO2). These candidate “transfer reference materials” were selected because they are non-radioactive and because of their relevance to thermal property measurements on nuclear materials typically investigated at JRC-ITU (e.g. UO2, PuO2, molten salts). This work has been performed in the framework of the joint research project “ENG08 MetroFission” which is supported by the European Metrology Research Programme. This paper describes the metrological facilities that have been implemented for the measurement of the thermophysical properties of solid materials at very high temperature and presents the results of measurements obtained by all partners with these apparatus on some selected materials. The research leading to these results has received funding from the European Union on the basis of Decision No 912/2009/EC.JRC.E.3-Materials researc

Metrological Characterization of a High-Temperature Hybrid Sensor Using Thermal Radiation and Calibrated Sapphire Fiber Bragg Grating for Process Monitoring in Harsh Environments

Fiber Bragg gratings inscribed in single crystalline multimode sapphire fibers (S-FBG) are suitable for monitoring applications in harsh environments up to 1900 °C. Despite many approaches to optimize the S-FBG sensor, a metrological investigation of the achievable temperature uncertainties is still missing. In this paper, we developed a hybrid optical temperature sensor using S-FBG and thermal radiation signals. In addition, the sensor also includes a thermocouple for reference and process control during a field test. We analyzed the influence of the thermal gradient and hotspot position along the sensor for all three detection methods using an industrial draw tower and fixed point cells. Moreover, the signal processing of the reflected S-FBG spectrum was investigated and enhanced to determine the reachable measurement repeatability and uncertainty. For that purpose, we developed an analytical expression for the long-wavelength edge of the peak. Our findings show a higher stability against mechanical-caused mode variations for this method to measure the wavelength shift compared to established methods. Additionally, our approach offers a high robustness against aging effects caused by high-temperature processes (above 1700 °C) or harsh environments. Using temperature-fixed points, directly traceable to the International System of Units, we calibrated the S-FBG and thermocouple of the hybrid sensor, including the corresponding uncertainty budgets. Within the scope of an over 3-weeks-long field trial, 25 production cycles of an industrial silicon manufacturing process with temperatures up to 1600 °C were monitored with over 100,000 single measurements. The absolute calibrated thermocouple (Uk=2≈1K…4K) and S-FBG (Uk=2≈10K…14K) measurements agreed within their combined uncertainty. We also discuss possible strategies to significantly reduce the uncertainty of the S-FBG calibration. A follow-up measurement of the sensor after the long-term operation at high temperatures and the transport of the measuring system together with the sensor resulted in a change of less than 0.5 K. Thus, both the presented hybrid sensor and the measuring principle are very robust for applications in harsh environments

LEXIS weather and climate large-scale pilot

The LEXIS Weather and Climate Large-scale Pilot will deliver a system for prediction of water-food-energy nexus phenomena and their associated socio-economic impacts. The system will be based on multiple model layers chained together, namely global weather and climate models, high-resolution regional weather models, domain-specific application models (such as hydrological, forest fire risk forecasts), impact models providing information for key decision and policy makers (such as air quality, agriculture crop production, and extreme rainfall detection for flood mapping). This paper will report about the first results of this pilot in terms of serving model output data and products with Cloud and High Performance Data Analytics (HPDA) environments, on top a Weather Climate Data APIs (ECMWF), as well as the porting of models on the LEXIS Infrastructure via different virtualization strategies (virtual machine and containers)

Photonic and Optomechanical Thermometry

International audienceTemperature is one of the most relevant physical quantities that affects almost all processes in nature. However, the realization of accurate temperature standards using current temperature references, like the triple point of water, is difficult due to the requirements on material purity and stability of the environment. In addition, in harsh environments, current temperature sensors with electrical readout, like platinum resistors, are difficult to implement, urging the development of optical temperature sensors. In 2018, the European consortium Photoquant, consisting of metrological institutes and academic partners, started investigating new temperature standards for self-calibrated, embedded optomechanical sensor applications, as well as optimised high resolution and high reliability photonic sensors, to measure temperature at the nano and meso-scales and as a possible replacement for the standard platinum resistant thermometers. This article presents an overview of the results obtained with sensor prototypes that exploit photonic and optomechanical techniques for sensing temperatures over a large temperature range (5 K to 300 K). Different concepts are demonstrated, including ring resonators, ladder-like resonators and suspended membrane optomechanical thermometers, highlighting initial performance and challenges, like self-heating that need to be overcome to realize photonic and optomechanical thermometry applications