International and National Journals
F. Righini, T. Matsumoto
The role of national measurement institutes in subsecond current-heating methods
International Journal of Thermophysics 26 (4), pp. 941-955, 2005.
The classical millisecond-resolution pulse-heating method makes use of tubular specimens with a rectangular blackbody hole for accurate measurements of several thermophysical properties at high temperatures. An alternative measurement technique that uses simple strip specimens has been developed at the IMGC (Italy). The normal spectral emissivity of the pulse-heated strip is measured by integrating sphere reflectometry, using a modulated laser beam to discriminate between the reflected radiation and that self-emitted by the specimen. After a brief description of the measurement system and a review of the main experimental results, attention is devoted to current developments and possible improvements of the method, with particular attention to experiments performed at the melting point. The measurement technique is analyzed and evaluated, with a brief description of potential future measurement possibilities.
B. Fellmuth, L. Wolber, Y. Hermier, F. Pavese, P.P.M. Steur, I. Peroni, A. Szmyrka-Grzebyk, L. Lipinski, W.L. Tew, T. Nakano, H. Sakurai, O. Tamura, D. Head, K.D. Hill, A.G. Steele
Isotopic and other influences on the realization of the triple point of hydrogen
Metrologia 42 (4), pp. 171-193, 2005.
Within an international collaboration of the eight metrological institutes represented by the authors, the dependence of the triple-point temperature of equilibrium hydrogen on the deuterium content at low concentrations has been precisely determined so that the uncertainty in realizing the triple point as a temperature fixed point might be reduced by nearly one order of magnitude. To investigate the thermodynamic properties of the hydrogen-deuterium mixtures and to elucidate the factors that influence the melting temperature, 28 sealed fixed-point cells have been filled and measured, and some of these have been compared with an open-cell system. Hydrogen gas with a deuterium content ranging from 27.2 µmol D/mol H to 154.9 µmol D/mol H was studied using cells containing five different types of spin-conversion catalyst, with different catalyst-to-liquid volume ratios (a few per cent to more than 100%) and of different designs. The latter consideration is especially influential in determining the thermal behaviour of the cells and, thus, the temperature-measurement errors. The cells were measured at the eight participating institutes in accordance with a detailed protocol that facilitates a direct comparison of the results. Through analysis of the measurements, significant inter-institute deviations due to different measurement facilities and methods have been ruled out with respect to the determination of both the melting temperatures and the thermal parameters of the cells.
The uncertainty estimates for the determination of the deuterium content have been verified by including isotopic analysis results from four different sources. The slope of the dependence of the triple-point temperature of equilibrium hydrogen isotopic mixtures on the deuterium content has been deduced from the melting temperatures of those sample portions not in direct contact with the catalysts. Evaluation of the data using different mathematical methods has yielded an average value of 5.42 µK per µmol D/mol H, with an upper bound of the standard uncertainty of 0.31 µK per µmol D/mol H. This is close to the literature value of 5.6 µK per µmol D/mol H that was obtained at higher deuterium concentrations.
F. Pavese, B. Fellmuth, D.I. Head, Y. Hermier, K.D. Hill, S. Valkiers
Evidence of a systematic deviation of the isotopic composition of neon from commercial sources compared with its isotopic composition in air
Analytical Chemistry 77 (15), pp. 5076-5080, 2005.
Results of a study are reported concerning the variation in isotopic composition of a limited number of neon samples of commercial origin and the resulting influence on the temperature of the triple point of this element. All seven neon samples investigated were found to contain more 22Ne than neon in air and the amount fraction of 22Ne varied by as much as 0.2% from sample to sample. This variation corresponds to a range of triple-point temperatures (Ttp) of more than 200 µK, much larger than the state-of-the-art uncertainty in the realization of this phase transition for metrological purposes. Deviations in the amount fractions of 21Ne were irrelevant, as far as their effect on Ttp is concerned, though they may have relevance to other isotope studies. Ratios of amounts of neon isotopes at IRMM-Geel were obtained using the same measurement procedures and instrumentation developed in the framework of the re-determination of the Avogadro constant and all significant sources of uncertainty were taken into account. The repeatability of the ion current ratio measurements on individual samples was 5·10-5 relative. All uncertainty statements are made following the ISO/BIPM Guide to the Expression of Uncertainty in Measurements. Whereas these results proved unexpected, a more comprehensive study will follow incorporating a much wider range of samples of commercial origin.
F. Pavese
Comments on "Statistical analysis of CIPM key comparisons based on the ISO Guide"
Metrologia, 42 (1), pp. L10-L12, 2005.
The paper by Kacker et al (2004 Metrologia 41 340-52) takes a systematic approach to the key comparison reference value and the degree of equivalence. Their approach seems of particular interest on three issues that are discussed here.
V.C. Fernicola, R. Galleano
A multi-channel optical fibre thermometer
Measurement, 37 (1), pp. 1-8, 2005.
As part of a project aimed at identifying unsatisfactory temperature distributions within foods heated in microwave ovens, a multi-channel optical fibre temperature system based on fluorescence thermometry has been developed. The system consists of a digital fluorescence lifetime thermometer, a 12-channel optical fibre multiplexer and a set of fully dielectric optical fibre probes. A custom analog-to-digital signal processing (A-DSP) for fluorescence lifetime detection was developed and special probes, suitable for microwave oven applications, were constructed. The multi-channel thermometer was calibrated by comparison against a platinum resistance thermometer traceable to ITS-90 in the temperature range 0-150 ºC. The system affords a temperature repeatability to within 0.3 ºC, with 0.5 s response time. Overall system performance and probe calibration are reported. Examples of temperature distribution measurements within food analogues heated in microwave ovens are reported, as well.
F. Pavese
On problems in the definition of the International Temperature Scale arising from the variability of the isotopic composition of some substances used for the fixed-points
Metrologia 42 (4), pp. 194-200, 2005.
The definition of the International Temperature Scale, ITS-90, requires the substances used for the realization of the fixed-points, except 3He, to be of "natural" isotopic composition. The uncertainty of the best fixed-point realizations for some of these substances is today significantly affected by the natural variability of the isotopic composition of the available samples. The paper discusses the main implications of this problem, which is becoming an obstacle to further improvements for some of the fixed-point realizations. In addition, the two main solutions are compared: (i) to define only a reference composition and (ii) to define a reference composition and allow the use of a correction for the deviations from a reference composition.
D. Ichim, M. Astrua
A statistical procedure to quantify the conformity of new thermocouples with respect to a reference function
Published as short communication in "AMCTM VII, World Scientific, Singapore", pp. 301-305, 2005.
The problem of assessing the degree of conformity of an artefact with respect to a standard model is addressed. Three possible strategies are proposed: the correlation coefficient, a least squares approach and the concordance correlation coefficient. These techniques are compared when applied to assess the conformity of six new Platinum-Palladium thermocouples with respect to the NIST/IMGC emf-temperature function.
D. Ichim, P. Ciarlini, E. Badea, G. Della Gatta
Non-parametric methods to evaluate derivative uncertainty from small data sets
Published as short communication in "AMCTM VII, World Scientific, Singapore", pp. 306-309, 2005.
Linear models describing the behaviour of the molar enthalpy of solution at infinite dilution,ΔsolH∞m, as a function of temperature are considered in a hydrophobic hydration study. Purpose of this work is to evaluate the ΔsolH∞m = f(T) function, its point derivative and associate uncertainty, when information available for data modelling is rather limited from a statistical point of view. Methods not requiring the assumption of strict conditions on data probability are used.
F. Pavese
Some problems concerning the estimate of the degree of equivalence in MRA key comparisons and of its uncertainty
Published as short communication in "AMCTM VII, World Scientific, Singapore", pp. 325-329, 2005.
The meaning of the degree of equivalence of each laboratory mainly depends on the meaning of the key comparison reference value, and this, in turn, depends on the type of key comparison and on the type of outcomes that each specific key comparison provides. Commonly, the proposed statistical approaches for the treatment of data of MRA exercises do not account for most of these specificities. This paper shortly addresses instead them and the problem of the estimate of the degree of equivalence for certain types of key comparison and of the associated uncertainty.
A. Merlone, S. Giunta, P. Marcarino
Amplificatore di temperatura
Tutto Misure, anno VII, n. 03, pp. 233-234, 2005.
P. Marcarino, A. Merlone, R. Gavioso
Metodi per una nuova determinazione della costante di Boltzmann - progetto Euromet n. 774
Tutto_Misure, anno VII, n. 3, p. 253, 2005.
Presso il PTB di Berlino, il 21 gennaio 2005, si è tenuto il "Workshop on methods for new determinations of the Boltzmann constant", finalizzato ad analizzare lo stato attuale di avanzamento dei lavori riguardanti la determinazione della costante di Boltzmann. L'evento è stato organizzato dal PTB in ambito Euromet, con invito esteso a partecipanti da tutto il mondo (Canada, USA, Giappone e altri). Il lavoro portato avanti, a partire dal 2000, dal gruppo temperature intermedie dell'IMGC e dal gruppo di acustica fisica dell'IEN è ormai internazionalmente noto ed è stato definito come il risultato attualmente di maggiore interesse. I nostri risultati pubblicati e presentati al congresso hanno confermato le deviazioni rispetto alle temperature termodinamiche della ITS-90, misurate mediante termometro acustico, rafforzando così la necessità di una revisione dell'attuale scala di temperature.
Conference Proceedings
A.G. Chunovkina, P. Ciarlini, M.G. Cox, F. Pavese
Handling and treatment of measurement data from different groups or sources
Proceedings of the 10th IMEKO TC7 International Symposium on Advances of Measurement Science, pp. 176-180, St. Petersburg, June 2004 (on cd rom).
This paper addresses the problem of evaluation of data acquired from different groups or sources. It concentrates on a grouping of measurement tasks into (1) measurand value estimation, (2) quantification of the quality of the measurement method, (3) quantification of the comparison of measurement quality. The emphasis is on appropriate use of statistical methods for parameter estimation, experiment design and testing hypothesis for measurement data evaluation.
P. Marcarino, G. Bonnier
Temperature amplifier by means of coupled gas-controlled heat-pipes
(Plenary Lectures) Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 33-47, 2005.
BNM-INM and IMGC-CNR have been working during many years in the field of Gas-Controlled Heat-Pipes (GCHPs). These devices have been specifically developed for accurate temperature measurements, with ever improving thermal characteristics during the last 30 years.
A GCHP is based on the thermodynamic properties of the liquid-vapor transition of a given working fluid under a controlled pressure. The measuring zones of the more recent GCHPs, connected to an accurate pressure controlled line, present a temperature uniformity and stability at the millikelvin level in a very large range of temperature. The basic principles of GCHPs are reviewed and the most important results achieved by using this device in thermometry are presented. By applying the same pressure to several GCHPs using different working fluids, the temperature in one
GCHP is thermodynamically related to the temperature in another GCHP. It means that any temperature of a given working fluid, i.e. between 240 ºC and 400 ºC for a mercury GCHP, is able to be "amplified" in order to establish an unique and very reproducible higher temperature in another working fluid, i.e. between 660 ºC and 962 ºC for a sodium GCHP. This instrument, called "Temperature Amplifier" (TA), allows a considerable improvement in the calibration process of SPRTs at high temperature. Indeed, the operating temperature of the reference SPRT in the low temperature GCHP can be limited to 400 ºC, and, consequently, the stability and reproducibility in the high temperature GCHP are largely improved. The experimental results lead to the possibility to use the TA above the Aluminum point as a possible alternative instrument in a future temperature scale.
P.P.M. Steur, I. Peroni, D. Ferri, F. Pavese
Interpolating gas thermometry with a cryogenic absolute pressure sensor
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 141-146, 2005.
Since several years an interpolating constant-volume gas thermometer (ICVGT) is operating at IMGC-CNR. This gas thermometer is equipped with a low-temperature differential pressure transducer made of sapphire. Details on the pressure transducer behaviour and results for the ICVGT have been presented at the 8th Temperature Symposium of 2002. Up to now the pressure transducer has been applied only in the differential mode, with the reference pressure supplied by a RUSKA pressure balance. Subsequently, the behaviour of the pressure transducer in the absolute mode has been studied and the transducer has been calibrated in situ at pressures between 1,8 kPa and 70 kPa. After pressure calibration of the transducer, a few runs have been performed with the ICVGT at temperatures between 4,2 K and 24,6 K for two different densities. This paper presents the findings on the behaviour of the transducer in absolute mode and on its calibration. Next, the results of the measurements performed with the ICVGT with the two different densities in comparison with a calibrated rhodium-iron resistance thermometer are given. Finally, also a comparison of ICVGT results using the pressure transducer in the differential mode with those obtained with the transducer in the absolute mode are presented.
D. Ferri, D. Ichim, F. Pavese, I. Peroni, F. Sparasci, P.P.M. Steur
Low-temperature fixed points realization using a cryogen-free refrigerator
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 165-170, 2005.
In the framework of the European Project Multicells, a new generation of sealed temperature fixed-point cells has been developed. The cells based on the principle of modular elements, each containing one substance, realise the low-temperature fixed points of the ITS-90 (International Temperature Scale of 1990). Up to six cells can be mounted in a copper frame, where the thermometers are fitted. In order to accommodate the Multicells Project output devices, a cryostat with a cryogen-free refrigerator has been designed and built at the Istituto di Metrologia "G. Colonnetti". The cryostat uses a Gifford-McMahon refrigerator with two cooling stages, and is interfaced with a system for temperature control and data acquisition. Therefore, triple point temperature measurements are carried out automatically. The operational characteristics of the cryostat are presented as well as its performance during the realisation of phase transitions and the measurement of triple points. The main thermal parameters for the cells measured with this cryostat are in agreement with those obtained by others. Measurement noise is less than 30 µK. Examples are given of thermometer calibration at the fixed-points of hydrogen and neon, performed automatically in a single run. The uncertainty budget of these fixed point cells is improved with respect to that of the previous generation of cells.
A. Merlone, P. Marcarino
The "Temperature Amplifier" for very accurate temperature measurements between Al and Ag fixed points
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 227-232, 2005.
In the course of a study on the behavior of coupled Gas-Controlled Heat Pipes (GCHPs), for the first time perfect agreement has been obtained between measurements on the immersion characteristics in a mercury GCHP and the Clausius?Clapeyron profile. This result opened the perspective of using coupled GCHPs to thermodynamically relate two different temperature ranges, with the possibility of redefining one temperature range in terms of another. Indeed, by controlling the helium pressure by means of a SPRT inserted in the thermometer well of the mercury GCHP, any temperature in the range between 240 ºC and 400 ºC can be "amplified" in a sodium heat-pipe connected to the same helium line, to one, unique and very reproducible temperature in the range between 660 ºC and 962 ºC. This device, called "Temperature Amplifier" allows a temperature reproducibility between 660 ºC and 961 ºC that surpasses that of the High Temperature Standard Platinum Resistance Thermometer (HTSPRTs) used for the ITS-90. The technique opens therefore the prospect of realizing the ITS in a different way: any accurate reproducible temperature range may be used to generate another temperature range, the relationship between the two ranges being thermodynamically related by the two pure substances used for the vapor-liquid transitions. For pure mercury and sodium, the relationship has already been determined and the results presented at the "8th Temperature Symposium" held in Chicago in 2002. The present work analyses this result and the accuracy improvement in using the "Temperature Amplifier" for the realization of the future ITS between the Al and Ag fixed points.
A. Merlone, P. Marcarino, R. Dematteis, C. Bassani
New gas-controlled heat pipes
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 415-419, 2005.
New Gas-Controlled Heat Pipes (GCHPs) have been manufactured for primary resistance thermometry purposes, and are now commercially available. The design of the new heat pipes is an improvement of the design of the heat pipes manufactured some years ago at JRC and takes into account all recent studies carried out at IMGC on this kind of devices. Inconel heat pipes are now available for being filled with potassium or sodium as working fluids for high temperature measurements. Stainless steel heat pipes have also been manufactured, to be filled with low-temperature working fluids, such as mercury. Six-well and three-well pipes are available, both for higher or lower temperature, on request. A new pressure control system is being developed too: it's been designed purposely for the control of the pressure inside the heat pipes, by acting on the pressure of the controlling gas. This controller can use a Platinum Resistance Thermometer (PRT) as sensor, through its reading by an automatic F18 bridge processed by a computer passed on to the controller. The GCHPs are equipped with dedicated new furnaces, new power-control systems and cooling lines. Two or more GCHPs can be connected to the same pressure controlled line in order to realise the "Temperature Amplifier" or to obtain continuous temperature ranges for thermometer calibration, from 200 ºC to 1000 ºC. The new heat pipes are here presented together with an overview of all the dedicated equipment designed and manufactured.
A. Merlone, P. Marcarino, A. Tiziani
A new laboratory for gas-controlled heat pipes at IMGC
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 421-425, 2005.
At IMGC a new laboratory has been set-up. It will host all the activities related to the studies and the measurements on the Gas-Controlled Heat Pipes (GCHPs). Since now, all research was carried out in the laboratory for ITS?90 fixed points. A new, considerable, investment has been made at IMGC, in order to fund the new laboratory with all the required instrumentation, informatics and equipment. The investment has now been approved, as the results achieved since now on the GCHP gathered significant interest in the national and international scientific communities. The device called "Temperature Amplifier" is one of the promising systems for very accurate temperature measurements in a wide range of resistance thermometry, and for the improvement of the temperature scale between the Al and Ag fixed points. All practical activities related to the development of the "Temperature Amplifier" will be carried out in this new laboratory. The laboratory hosts furnaces, pressure controllers and pressure lines, several kinds of heat pipe, resistance bridges and all related equipment. The activities range from temperature measurement, to the cleaning and filling of heat pipes and device characterization, both for industrial applications and temperature standards. The paper presents the set-up of the new laboratory, its equipment, its activities, the results achieved and the projects planned.
M. Astrua, M. Battuello, R. Dematteis, A. Mangano
Construction and investigation of six Pt/Pd thermocouples to be used as secondary standards
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 465-470, 2005.
A lot of six Pt/Pd thermocouples were constructed and investigated at IMGC with the aim of replacing the presently used Pt/Pt-Rh alloy thermocouples as secondary reference standards up to 1500 ºC. Pt and Pd wires from three different manufacturers and of different nominal purity were used. The effects of heat treatments in air at 1100 ºC were measured by comparing each Pt/Pd thermocouple with a Au/Pt thermocouple in a gas-controlled potassium heat-pipe. The heat-pipe was also used for a determination of the homogeneity of the thermocouples. Each thermocouple was then calibrated at the fixed-points of Ag, Al, Zn, Sn, In and at the triple point of water. Preliminary results on the use of a new furnace for the calibration of the thermocouples by comparison with the IMGC standard radiation thermometer up to 1500 ºC are also reported.
M. Battuello, F. Girard, T. Ricolfi
An improved version of the IMGC InGaAs precision infrared thermometer
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 505-508, 2005.
A precision infrared thermometer using a InGaAs photodetector was modified in order to suppress the nonlinearity in its output signal. This result was obtained by increasing the sensing area of the photodetector thus eliminating the edge effect that generated the nonlinearity. The main advantage from this improvement is that a simpler interpolation equation can be used to fit the calibration data.
B. Trinchera, M. Battuello, F. Girard
The MCZT, a candidate detector for low temperature radiation thermometry
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 617-622, 2005.
Experimental investigations on different infrared detectors have been carried out at IMGC in view of constructing a precision instrument to be used as a transfer standard for low temperature thermometry. A new photoelectric detector type, the HgCdZnTe (MCZT), was tested and compared with some HgCdTe (MCT) detectors. The results in terms of temperature resolution suggested that the new thermoelectrically cooled MCZT may be an alternative to the liquid nitrogen cooled MCT detectors.
F. Arpino, M. Dell'Isola, V. C. Fernicola, A. Frattolillo, L. Rosso
Design and modelling of a surface temperature calibration system
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 635-641, 2005.
The calibration of contact surface temperature sensors depends on several influence parameters such as the contact thermal resistance, the body thermal conductivity, the geometry of the probe, the temperature of the surrounding fluid, etc. An accurate calibration call for an actual and efficient control of the above-mentioned parameters in order to reduce their effects during a calibration run. Some of them could also be varied in order to simulate the specific operating conditions of the probe. The paper describes the design and modeling of a dedicated calibration system for contact surface temperature sensors. The system is based on a high thermal capacity block, whose surface temperature can be controlled in the temperature range from ambient to about 350 ºC. The system is initially modeled and its operation simulated using a numerical code to optimize its geometry and operating conditions as well as to highlight the critical points to be monitored in the actual operation. A mechanical design was performed on the basis of the numerical calculations and a first prototype was constructed. A preliminary characterization is carried out and the results are reported in the paper. A preliminary comparison of the numerical model with the experimental results is made in order to validate the model.
V.F. Mitin, N.S. Boltovets, V.V. Basanets, V.V. Kholevchuk, I. Yu. Nemish, F. Pavese, P.C. McDonald
Ge-GaAs thermometers and multisensor for temperature and magnetic field measurements
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 643-647, 2005.
This paper presents a review of germanium-film resistance thermometers and multifunction sensors; for concurrent measurements of temperature and magnetic fields, which have been developed using microelectronic design and production methods, in an international collaboration, supported by the European Union. A range of resistance thermometers has been developed, to provide high sensitivity over complementary temperature ranges, within the overall range 0.03 to 500 K. The temperature sensitive elements used in these thermometers are produced by the deposition of germanium (Ge) onto semi-insulating gallium arsenide (GaAs) substrates and these have been incorporated in a number of different thermometer packages. A new multisensor has been designed, which consists of a Ge-film resistance thermometer and a InSb-film Hall generator. The multisensor is intended for use in the 1 to 400 K temperature range and magnetic field up to 30 Tesla. We present the thermometric properties and magnetic field effects for different types of the Ge-GaAs resistance temperature sensors.
G.C. Bussolino, A. Actis, F. Girard
Push-rod dilatometry measurements at IMGC
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 765-770, 2005.
A push-rod dilatometer, operating from room temperature up to 1250 K, has been developed at Istituto di Metrologia "G. Colonnetti" (IMGC). The apparatus was designed for solid specimens having cylindrical shape. After mechanical measurement of the length at the reference temperature of 293 K, the specimen is then housed inside a fumace, in order to obtain thermal expansion as a function of temperature, detected by means of a laser interferometer system in conjunction with simultaneous temperature measurement. The apparatus is described and measurements on SRM 738 (stainless steel) are reported, along with a description of possible improvements in the future.
P. Marcarino, A. Merlone, P.P.M. Steur, A. Actis, M. Antinori
Proposal: new reference functions for industrial platinum resistance thermometers
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 807-812, 2005.
The Callendar - Van Dusen (CVD) equations of the IEC-751 for Industrial Platinum Resistance Thermometers (IPRTs) do not exactly follow the International Temperature Scale of 1990 (ITS-90) and do not allow an interpolation uncertainty better than ± 0.2 K over a range larger than 0 ÷ 250 ºC, while the users require a much better accuracy. Recently, two new reference equations have been proposed as a modification of the CVD, one for the temperature range from -200 ºC to 0 ºC and the other for the range from 0 ºC to 850 ºC. The proposed equations only add higher order terms to the CVD equations, while the lowest order coefficients remain equal to the constants A, B and C of the CVD. Using a set of 36 thermometers, calibrated in the range between -80 ºC and 650 ºC, it has already been shown that the interpolation accuracy of ±0.05 ºC obtained by the CVD equations is reduced by the use of the new equations well within ±0.01 ºC, being this the accuracy of calibration. Also the original data set that gave rise to the present IEC-751 have been tested with the proposed equations. In addition a large set of high-quality IPRTs has been tested, with alpha values ranging from 0.00385 ºC-1 to values not far from those required for Standard Platinum Resistance Thermometers (SPRTs). Finally, also some SPRTs have been included in the study to verify that the new equations allow an agreement with the ITS-90 well within 1 mK. Therefore, the new reference functions are valid for every type of platinum resistance thermometers, from those having low alpha (IPRTs) to those with very high alpha (SPRTs), thus comprising thermometers having stability and reproducibility at the level of 0.01 ºC, but that do not satisfy the requirements of the ITS-90.
F. Girard, T. Ricolfi
Analysis of two methods for calibrating IR thermometers in the middle-temperature range
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 827-832, 2005.
The comparison and the fixed-point methods for calibrating infrared thermometers are analyzed on the light of recent technical developments and interlaboratory comparisons. It is concluded that a better accuracy and reliability are obtained with the fixed-point method although the comparison method may be convenient for routine calibration works.
T. Ricolfi, F. Lanza
Simple method for the absolute calibration of radiant heat flux meters
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 903-908, 2005.
The evaluation of the convective heat-transfer component represents the major technical problem in the calibration of radiant heat flux meters. A simple experimental method is described that allows the convective component to be evaluated by measuring the meter output at two irradiance levels. Using this method, the maximum calibration uncertainty at the 95% confidence level has been estimated to be 3.4 %. The viability of this method was checked by calibrating a meter both in air and in vacuum, ie, in the absence of convective heat transfer. The results of the two calibrations agreed within better than 1%.
A. Merlone, P. Marcarino, L. Iacomini, A. Tiziani
A liquid bath for accurate platinum resistance thermometers calibration at IMGC
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 929-933, 2005.
At IMGC-CNR a liquid oil bath has been designed, manufactured and characterized. It is intended to provide a suitable device for platinum resistance thermometer calibration at the millikelvin level in the range from - 20 ºC to 100 ºC. This performance is obtained by placing the central measuring zone inside the controlling volume, where the heater and cooler are placed. A stirrer continuously flows the liquid from the controlling to the measuring zone. The temperature of the bath in the measuring zone is stable within a few tenths of a millikelvin in the whole range over a period of several days and is independent of fluctuations in ambient temperature. The bath shows a vertical and axial temperature uniformity within a few tenths of a millikelvin over 10 cm in the central part of the measuring zone. Temperature control is obtained by means of a Platinum Resistance Thermometer placed in the measuring zone immediately after the stirrer and a heating system in the controlling zone very close to the stirrer. Cool down from ambient temperature is obtained by an external commercially available thermostat circulating cooled alcohol in the heat exchanger placed in the controlling zone. The paper describes the bath and the temperature control system and loop. The data acquired during the characterization of the bath are reported.
D. Ichim, I. Peroni, P.P.M. Steur
Testing the breakpoint regression of resistance thermometer calibration data
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 935-940, 2005.
For several kinds of resistance thermometer, the approximation of calibration data, acquired by comparison, is generally a very subjective procedure. In this case there is no pre-defined rule for the choice of the model and the approximation method, one can try as many combinations as feasible. Poor model performance may be due to a wrong model or to an improper choice of the fitting range. Often, in case the fitting results are poor with respect to the expected/required criteria, splitting the data in two or more subsets is one of the used methodologies. Usually the decision of grouping the data in two parts and the choice of the breakpoint are done in a subjective manner, mainly graphically analysing the regression residuals. This paper presents a statistical test used to determine if the dataset has to be split or not. If the decision is taken to divide the data in subsets, the estimation of breakpoints is performed. In this work only the case of a single unknown breakpoint is considered. The method proposed here provides criteria based on a structural change test for splitting the data. It also identifies the subsets to be used in the parameter estimation procedures. Moreover, the use of the same splitting criteria and procedure based on the same statistic to the same kind of data will produce highly consistent results. The procedure depends on the adequacy of the involved class of models. The paper presents the statistical test applied to the calibration of different types of cryogenic resistance thermometers. Results of splitting point estimation are given for the approximation of the Resistance-Temperature characteristic for some rhodium-iron, platinum, germanium and Cernox thermometers.
P. Ciarlini, A. Chunovkina, F. Pavese, G. Regoliosi
The assessment of the degree of equivalence and the use of mixture distribution models in temperature metrology
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 1003-1008, 2005.
In inter-comparisons the definition of the "degree of equivalence", now widely discussed in the metrological community, is a complex problem related to the concept of "uncertainty" that is associated to the output Reference Value. Many metrological and statistical aspects related to the specific conditions stated in the MRA for the IC's, are not fully described in the document and should be part of additional recommendation in order to be uniquely defined and appropriately computed. The paper discusses the occurrence of outlying biases and of broad differences among the uncertainties provided by the participants. The paper introduces the mixture probability distribution model in metrology, i.e., in the calibration context, and discusses it possible adoption also in the testing context. In temperature the mixture model enables to represent the probabilistic characteristics of the individual laboratory in a single context and to assess the "degree of equivalence" and its uncertainty, as related to the "quality"of the participating laboratories.
S. Ugur, A. Uytun, V.C. Fernicola, M. Banfo
Measurements of humidity standards at UME (Turkey) and at IMGC-CNR (Italy). A bilateral comparison
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 1025-1030, 2005.
A bilateral comparison between UME and IMGC was carried out in the field of humidity from -30ºC to 60ºC dew/frost point temperatures. Two circulating chilled-mirror dew point transfer standards are measured, both in terms of the DC analog output and the Pt-100 mirror PRT reading, and the result of the comparison has been evaluated in terms of these two quantities. The agreement between the results of the measurement at UME and those obtained at IMGC-CNR in the common dew/frost point temperature range -30 ºC to 60 ºC is found to be within the comparison uncertainty. The detailed analysis of the results and the uncertainty budget related to the measurements is presented in this work.
Y. Hermier, G. Bonnier, V. Chimenti, D. Del Campo, E. Grudniewicz, P. Marcarino, P.P.M. Steur, E. Filipe, I. Lobo, N. Machado, C. Rauta, F. Helgesen, A. Steiner, T. Weckström, J. Bojkovski, J. Nielsen, J. Dubbeldam, D.I. Head, S. Bruce, R. Rusby, B. Fellmuth, B. Thiele-Krivoj, J. Ivarsson, M. Kalemci, S. Ugur
Intercomparison of argon triple point cells in the frame of EUROMET Project 502
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 1037-1042, 2005.
The argon triple point is, in most cases, the lower temperature fixed point used in the calibration of the long stem SPRTs to be calibrated in the ITS-90 (T90= 83,805 8 K). Considering that a mercury fixed point cell comparison had already taken place in the frame of EUROMET (Project No.280), and in order to provide more information for the establishment of CMCs in Europe, in the low temperature range, it was considered as useful to organize a comparison of argon triple point cells, and this was done in the frame of EUROMET (Project No.502). The main objective of this project was to compare the realizations of the argon triple point cells for long stem thermometers and to establish the level of agreement between the results from the different participating laboratories. BNM-INM proposed to circulate one argon triple point cell, together with the cryostat. The comparison measurements consisted of a described set of triple point determinations on both the circulating device and the local one. The calibration facilities were circulated with a fully described procedure to realize the fixed point and a protocol for the comparison (as agreed between the different partners). This project enabled the measurement of the temperature differences between the different devices and the associated uncertainty of these differences. The paper will present the set-up of the comparison, the preliminary experimental results obtained and a link between national realizations of the argon triple point as a consequence. The uncertainty on the comparison for each participating laboratory is around 0.5 mK. The standard deviation on the mean is also around 0.5 mK, demonstrating the comparison is quite robust.
F. Edler, M. Albrecht, V. Chimenti, D. Del Campo, A. Duke, D. Head, P. Marcarino, P.P.M. Steur, R. Dematteis, M. Megharfi, I. Didialaoui
Intercomparison of Pt/Pd thermocouples calibrated at the freezing points of copper and silver
Proceedings of the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), Cavtat (Dubrovnik, Croatia), June 2004, ed. D. Zvizdic, L. G. Bermanec, T. Stasic, T. Veliki, published by LBM, Zagreb (Croatia), pp. 1081-1086, 2005.
The intercomparison of Pt/Pd thermocouples calibrated at the freezing points of copper ( t90 = 1084.62 ºC) and Silver (t90 = 961.78 ºC) was the subject of the EUROMET project No. 624 in the field of thermometry. The intercomparison demonstrated the reproducibility of the calibration of Pt/Pd thermocouples at fixed points (copper and silver) in different laboratories, and also allowed for comparison of the freezing temperatures of different copper fixed points cells.
D. Ichim, F. Pavese, P. Ciarlini
Experimental design optimization: Case study - the calibration of large batches of cryogenic thermometers
Proceedings of the International Workshop "From Data Acquisition to Data Processing and Retrieval", Ljubljana, September 2004 (on cd rom).
In a calibration process of thousands of thermometers, optimization of the experimental design is an important step to save time and costs. In this paper a modelling procedure is proposed for the construction of a suitable cubic spline approximation of the R - T characteristic of cryogenic thermometers. An iterative algorithm is used to estimate the parameters of a free-knot cubic spline model. Moreover, the minimum number of measurement points and their locations in the experimental design, as related to the spline parameters, are obtained via an heuristic study.
V.F. Mitin, N.S. Boltovets, V.V. Kholevchuk, F. Pavese, P.C. McDonald, G.G. Ihas
Review of Ge-GaAs thermometers and multisensors for measurement of temperature and magnetic field in cryogenic applications
Proceedings LT24, August 2005.
This paper reviews the properties of a range of Ge-on-GaAs film resistance thermometers that cover the temperature range 0.03 K to 500 K. New dual element resistance thermometer is described, in which two temperature sensitive elements with overlapping thermometrical characteristics are combined to provide a thermometer with good sensitivity over the measurement range from 0.1 K to 400 K. A novel dual function sensor for concurrent measurements of temperature from 1.5 K to 400 K and magnetic field is also described. This consists of a Ge-GaAs resistance thermometer and an InSb-GaAs Hall-effect magnetic field sensor combined in a single package.
P. Marcarino, A. Merlone
Il tubo di calore a controllo di pressione per la misura accurata della temperatura
Atti del Congresso Metrologia e Qualità, pp. 191-194, Torino, febbraio 2005.
A. Merlone, S. Giunta, P. Marcarino, A. Coggiola
Tubo di calore a controllo di pressione al mercurio per tarature di termometri tra 250 ºC e 450 ºC
Atti del Congresso Metrologia e Qualità, pp. 195-198, Torino, febbraio 2005.
Presso l'Istituto di Metrologia "Gustavo Colonnetti" del Consiglio Nazionale delle Ricerche (l'IMGC - CNR) è da tempo attiva una linea di ricerca e sviluppo sui tubi di calore a controllo di pressione (Gas-Controlled Heat Pipes - GCHP). I GCHP stanno riscuotendo un crescente interesse sia in ambito internazionale sia a carattere nazionale, per molteplici impieghi. Questi dispositivi, inizialmente ideati per la ricerca nel campo della termometria primaria, si sono successivamente rivelati sistemi utili per l'esecuzione di tarature di termometri e termocoppie. Grazie alla stabilità e uniformità di temperatura, ottenibili entro il millesimo di kelvin, i GCHP vengono attualmente impiegati per tarature, a partire da 200 ºC, fino a 1000 ºC. Nuovi GCHP sono ora disponibili, appositamente disegnati e realizzati per tarature in ampi campi di utilizzo. In questo lavoro vengono presentati i principi di funzionamento e la caratterizzazione di un GCHP di nuova generazione, realizzato su disegno IMGC - CNR per il Politecnico di Torino. Il tubo utilizza mercurio come fluido di lavoro e elio come gas per la regolazione della pressione al suo interno. Il GCHP è utilizzabile nel campo tra 250 ºC e 450 ºC ed è corredato di sei pozzetti termometrici. Può essere utilizzato sia con un controllore di pressione commerciale, sia con quello appositamente realizzato, ora disponibile presso l'IMGC, che si basa su un Termometro a Resistenza di Platino. Il presente lavoro espone le caratteristiche costruttive del GCHP al mercurio e i dispositivi ad esso correlati. Il sistema complessivo è presentato in dettaglio, con descrizione dei singoli componenti: il sistema di potenza, il raffreddamento, il controllo di pressione e altri strumenti ausiliari. La metodologia di utilizzo per tarature di termometri campioni e termocoppie è riportata, insieme alla valutazione delle caratteristiche di funzionamento del tubo di calore. L'estensione del campo di impiego, fino a 1000 ºC è infine presentata, descrivendo la possibilità di associare al tubo al mercurio un tubo al cesio e uno al sodio o potassio.
A. Merlone, P. Marcarino
Amplificatore di temperatura: sistema innovativo ad alta riproducibilità e sensibilità per tarature di termometri a contatto
Atti del Congresso Metrologia e Qualità, pp. 199-202, Torino, febbraio 2005.
L'utilizzo di tubi di calore per tarature accurate di termometri primari, termocoppie e termometri industriali è da tempo consolidato presso i laboratori dell'IMGC - CNR. L'attività dell'IMGC sui tubi di calore finalizzata alla definizione della futura scala internazionale di temperatura tra 660 ºC e 962 ºC ha inoltre condotto a risultati di rilievo, pubblicati su riviste internazionali e presentati a congressi di molteplici settori scientifici. Il sistema, messo a punto e realizzato all'IMGC e denominato "Amplificatore di Temperatura" (TA), prevede l'accoppiamento di due tubi di calore riempiti uno con sodio e l'altro con mercurio, entrambi di elevata purezza, collegati alla stessa linea di controllo della pressione. L'elevata stabilità e ripetibilità di temperatura nel Hg, dell'ordine di pochi decimi di millesimo di kelvin, tra 240 ºC e 400 ºC viene amplificata nel tubo Na, tra 660 ºC e 962 ºC, ovviando ai noti problemi di instabilità e non unicità degli SPRT ad alta temperatura, risultando inoltre migliore rispetto alla ripetibilità delle misurazioni effettuate al punto di solidificazione Ag. Il lavoro descrive i risultati ottenuti finora con il primo prototipo di TA. Viene quindi presentato il nuovo TA realizzato dall'IMGC - CNR, costituito da nuovi tubi di calore, un nuovo sistema di controllo della pressione, controllo automatico della potenza, elettronica e software dedicati. I nuovi GCHP realizzati su disegno IMGC - CNR sono descritti, quali parti costitutiva del TA e, contemporaneamente, come singoli strumenti per tarature per confronto in ampi campi di temperatura. Il nuovo prototipo di sistema TA parteciperà al progetto Euromet 772, di cui l'IMGC - CNR è coordinatore. Diversi laboratori europei effettueranno misure sull'uniformità e stabilità di temperatura ottenute mediante il TA. Il sistema sarà infine disponibile per prove da parte di centri di taratura nazionali.
S. Giunta, A. Merlone, P. Marcarino
Sistema di controllo di pressione in tubi di calore per taratura di termometri
Atti del Congresso Metrologia e Qualità, pp. 209-212, Torino, febbraio 2005.
Un nuovo sistema di controllo della pressione per tubi di calore è stato disegnato e sviluppato presso l'Istituto di Metrologia "Gustavo Colonnetti" del Consiglio Nazionale delle Ricerche (l'IMGC - CNR). Il controllo si basa sul principio del "rapporto tra volumi"e garantisce sensibilità nella regolazione dell'ordine di 10-6, nel campo di pressione compreso tra 5 kPa e 500 kPa. Una serie di elettrovalvole è impiegata per l'attuazione del controllo in modalità totalmente automatica, mediante interfacciamento con calcolatore. Il sistema è principalmente dedicato al controllo di pressione e, conseguentemente, di temperatura nei tubi di calore a controllo di pressione (Gas-Controlled Heat Pipes - GCHP) e basa il suo funzionamento su un termometro a resistenza di platino (PRT) utilizzato come sensore di pressione. Da precedenti studi effettuati presso l'IMGC - CNR è emersa la possibilità di usare un PRT per misurare le variazioni di temperatura in un GCHP e regolare di conseguenza la pressione, al fine di controllare un "set-point" impostato. Il sistema verrà utilizzato per il controllo della pressione sia in GCHP dedicati alle tarature di termometri campione e industriali sia nell'"Amplificatore di Temperatura", per la realizzazione di una scala di temperatura a tensione di vapore nel campo tra i punti fissi dell'Al e dell'Ag. Accoppiato a un GCHP, il sistema può comunque essere utilizzato per il controllo fine della pressione, a prescindere dal suo utilizzo. Il lavoro presenta la descrizione completa del controllore di pressione, il suo funzionamento e le fasi di realizzazione. L'elettronica dedicata al controllo, interamente progettata e realizzata presso l'IMGC - CNR, è descritta nella sua struttura e funzionamento. Il software appositamente scritto per ottenere i controlli temporali necessari alle applicazioni previste è descritto nelle sue linee di principio. E' infine riportata la valutazione delle capacità del sistema.
Technical Reports
P.P.M. Steur, F. Pavese
On the definition of "pressure" in the ITS-90 definition of the Interpolating CVGT
Documento Comité Consultatif de Thermométrie CCT/05-03/rev, 2005.
A contribution is presented for the update of the "Supplementary Information for the ITS-90" with regards to the implementation of the Interpolating Constant-Volume Gas Thermometer (ICVGT). The ICVGT is the ITS-90 interpolating instrument for the temperature range between 3 K and 24.5561 K. An extension is presented of former simulation work on the behaviour of the ICVGT with different choices in experimental implementation. The central issue to be discussed here is which (absolute) pressure to use in the interpolation: a) measured at room temperature, or b) measured at the bulb. The merits and drawbacks of both cases will be highlighted.
P.P.M. Steur, Y. Hermier, K.S. Gam, K.D. Hill, B. Fellmuth, A.I. Pokhodun, D.C. Ripple
Isotopic effects in the hydrogen fixed points: Report to the CCT
Documento Comité Consultatif de Thermométrie CCT/05-06/rev(2), 2005.
In preparation for the upcoming revision of the "Supplementary Information for the ITS-90" (SuppInf) and following a much wider discussion beyond CCT WG1, this CCT document is intended to:
supply where possible the isotopic composition, correction equations, and related uncertainty for the three hydrogen fixed points.
D.C. Ripple, K.S. Gam, Y. Hermier, K.D. Hill, R.L. Rusby, A.G. Steele, P.P.M. Steur, M. Stock, G. F. Strouse, D.R. White
Summary of facts relating to isotopic effects and the triple point of water: Report of the ad hoc Task Group on the Triple Point of Water
Documento Comité Consultatif de Thermométrie CCT/05-07/rev and CCT/05-07a, 2005.
In the recent key comparison CCT-K7 "Key comparison of water triple point cells" clear differences were observed in the realized national standard for the triple point of water (TPW) between those laboratories that corrected for the deviation of isotopic concentration from Standard Mean Ocean Water (SMOW), and those laboratories that did not.
An ad hoc Task Group was formed to address this matter. The terms of reference for the Task Group were:
The present document, in conjunction with the proposed CCT Recommendation T1 (2005) to the CIPM, constitutes our recommendations to the CCT.
D.C. Ripple, B. Fellmuth, M. de Groot, Y. Hermier, K.D. Hill, P.P.M. Steur, A.I. Pokhodun, M. Matveyev, P. Bloembergen
Methodologies for the estimation of uncertainties and the correction of fixed-point temperatures attributable to the influence of chemical impurities
Documento Comité Consultatif de Thermométrie CCT/05-08, 2005.
Recent CCT Key Comparisons have exposed the fact that national metrology institutes use various means to estimate the uncertainty component of temperature fixed points that addresses the influence of impurities. Since this component often dominates the uncertainty budget, its importance cannot be understated. The lack of a common approach to the estimation of this component has created a situation whereby values for this single component may differ by orders of magnitude from lab to lab even though the materials and their treatment are generally very similar. We seek to standardize the methodology by proposing the Sum of Individual Estimates as the preferred method for estimating the change of the observed liquidus-point temperature relative to that of the chemically pure material where sufficient information is available to enable the required calculations. Where this is not possible, the Overall Maximum Estimate is an acceptable, though less desirable, alternative. The Estimate based on Representative Comparisons is specifically discouraged. The determination of the liquidus-point temperature from the freezing or melting curve is also discussed.
R.L. Rusby, M.R. Moldover, J. Fischer, D.R. White, P.P.M. Steur, K.D. Hill, R.P. Hudson, M. Durieux
Working Group 4 Report to CCT
Documento Comité Consultatif de Thermométrie CCT/05-19, 2005.
Following our established practice, the present report gives brief information on current projects to determine thermodynamic temperature, and refers to developments at altra-low temperatures. In a departure from previous practice, it also considers the implications of a possible redefinition of the SI unit of temperature, the Kelvin, in the light of the PTB workshop.
A. Merlone, P.P.M. Steur, P. Marcarino
Accurate determination of the mercury vapour pressure relation between 5 kPa and 200 kPa as reference function for the temperature amplifier
Documento Comité Consultatif de Thermométrie CCT/05-24, 2005.
At IMGC a gas-controlled heat-pipe (GCHP),using mercury as working fluid and helium as controlling gas, has been used to evaluate the vapour pressure curve of 7N pure mercury in the range between 5 kPa and 200 kPa, corresponding to the temperatures range between 225 ºC and 400 ºC. A standard pressure balance and a standard platinum resistance thermometer (SPRT) calibrated at the ITS-90 fixed points, were used. The experimental data obtained are fitted to a semi-empirical relationship between vapour pressure and temperature. The basic features of gas-controlled heat-pipes and the metrological level of the temperature and pressure measurements available in the laboratory, allowed the determination of the mercury vapour pressure at the level of a few parts in 10-5.
D.C. Ripple, Y. Hermier, P.P.M. Steur, E. Filipe, K.S. Gam, K.D. Hill, B. Fellmuth, A.I. Pokhodun
Report presented to the CCT By Working Group 1: May 2005
Documento Comité Consultatif de Thermométrie CCT/05-25, 2005.
The terms of reference of Working Group 1: defining fixed points and interpolating instruments (WG 1), as expressed in the Report of the 22nd Meeting of the CCT (2003) are:
F. Pavese
Final technical report and final publishable report - Network on Advanced Mathematical and Computational Tools in Metrology (www.amctm.org).
Contract no. G6RT-CT-2001-05061, SofTools_MetroNet.
F. Girard, M. Florio, M. Battuello
Construction and characterisation of the transfer standard radiation thermometer IMGC-TS3
The Istituto di Metrologia "G. Colonnetti" - IMGC (Italy) and the Instituto Português da Qualidade - IPQ (Portugal) are collaborating in thermometry research project since long time. Considering the long experience that the IMGC has in the design and construction of precision infrared radiation thermometers and the needs for IPQ to extend its measurement capability in radiation thermometry to the medium temperature range, the two Institutes have agreed to a project, in form of an international contract, called "Construction of thermometric apparatus for precise infrared temperature measurement in the temperature interval from 150 ºC to 1100 ºC". The primary objective of this project is the technical assistance to the IPQ with respect to the design, construction, assembly, operation and final testing of a precision infrared radiation thermometer to cover the temperature interval between the fixed point of indium (156 ºC) and copper (1084 ºC). The final purpose of this project is to deliver to the IPQ a prototype of a precision infrared thermometer for its own use. The complete work has been carried out by the authors, in the laboratory of radiation thermometry of the IMGC in ten months starting from last November, 2004. One additional week has been spent by an IMGC expert (F. Girard) at IPQ to instruct the customer and final users about the features of the new instruments delivered. This technical report describes the first part of the activity developed under this contract and in particular it contains:
1) the technical specifications of the thermometer
2) the optical layout and the electrical schemes
3) the characterization tests in terms of:
and it can be seen as a complete characterization tests, calibration procedure and operational guidelines for the thermometer.
F. Girard, M. Florio, M. Battuello
Transportable blackbody furnace for the accurate realization of the fixed point of tin
The Istituto di Metrologia "G. Colonnetti" - IMGC (Italy) and the Instituto Português da Qualidade - IPQ (Portugal) are collaborating in thermometry research project since long time.
Considering the long experience that the IMGC has in the design, construction and characterization of precision instruments in the field of the radiation thermometry and on the other side the needs for the IPQ of an equipment to realize a precision temperature reference in the medium temperature range, the two Institutes have agreed to a project, in form of an international contract, named "Construction of thermometric apparatus for precise infrared temperature measurement in the temperature interval from 150 ºC to 1100 ºC".
One of the objective of this project is the technical assistance to the IPQ with respect to the design, construction, assembly, operation and final testing of a transportable blackbody furnace to be used, in radiation thermometry, for the realization of temperature fixed points in the interval from 156 ºC (fixed point of In) to 420 ºC (fixed point of Zn).
The final purpose of this project is to deliver to the IPQ, for its own use, a prototype of a small-sized blackbody furnace equipped with a crucible filled with high purity tin for the realization of the Sn fixed-point.
The complete work has been carried out by the authors, in the laboratory of radiation thermometry of the IMGC in few months starting from last November, 2004. An additional week has been spent by an IMGC expert (F. Girard) at IPQ to install the apparatus and to instruct the customer and final users about the features of the new equipment delivered.
This technical report describes the second part of the activity developed under this contract and in particular it contains:
1) a general description of the apparatus for realizing the fixed points of tin
2) the technical specifications of the furnace
3) the technical specifications for the crucible of tin
4) the two procedures to run the melting and freezing plateau of tin respectively:
and it can be seen as a complete characterization tests for the apparatus that realize the fixed point of tin and an operational guidelines to running the furnace.
F. Girard, M. Florio, M. Battuello
Construction and characterisation of a precision transfer standard infrared thermometer for the temperature range from 150 ºC to 1100 ºC
The Istituto di Metrologia "G. Colonnetti" - IMGC (Italy) and the National Metrology Centre - NMC of the SPRING (Singapore) have collaborated in the recent past in various fields of metrology including radiation thermometry. Considering the long experience that the IMGC has in the design, construction and characterization of precision infrared radiation thermometers and the needs for NMC - SPRING to extend its measurement capability in radiation thermometry to the medium temperature range, the two Institutes have agreed to a project, in terms of an international contract, called "Construction and characterization of a precision Transfer Standard infrared radiation thermometer for the temperature interval from 150 ºC to 1100 ºC". The primary objective of this project is the technical assistance to the NMC - SPRING with respect to the design, construction, assembly, characterization and final testing of a precision infrared radiation thermometer to be used, at the NMC - SPRING, for calibration of radiation thermometers and blackbody sources in the temperature interval between the fixed points of indium (156 ºC) and copper (1084 ºC). The final purpose of this project is to deliver to the NMC - SPRING an easy transportable prototype of a precision infrared thermometer exclusively for its own use. The complete work has been carried out by the authors, in the laboratory of radiation thermometry of the IMGC in fifteen months starting from last October, 2004. One additional week will be spent during January, 2006 by an IMGC expert (F. Girard) at NMC - SPRING to provide the NMC - SPRING with staff training in the use of the new instrument delivered. This technical report describes the activity developed under this international contract and in particular it contains:
1) the technical specifications of the thermometer
2)the optical layout and the electrical schemes
3) the characterization tests in terms of:
and it can be seen as a complete characterization tests, calibration procedure and operational guidelines for the infrared transfer standard thermometer IMGC - TS4.
A. Merlone, L. Iacomini, A. Tiziani
A liquid bath for accurate platinum resistance thermometer calibration at IMGC
IMGC Technical Report no. 133, August 2005.
At the Thermometric division of the Italian Institute of Metrology (IMGC) a new liquid oil bath has been designed, manufactured and characterized with the aim to provide a suitable device thermometers calibrations at the millikelvin level in the range from - 10 ºC to 100 ºC. The temperature of the bath in the measuring zone is stable within a few tenths of a millikelvin in the whole range over a period of several days and it is independent from fluctuations of the ambient temperature. The bath shows a vertical and axial temperature uniformity within a few tenths of a millikelvin over 10 cm in the central part of the measuring zone. This performances are obtained by placing a central measuring zone inside a controlling volume, where a heater and a cooler are placed. A laminar flow of oil is continuously maintained from the controlling to the measuring zone. Temperature is controlled by means of a Platinum Resistance Thermometer placed in the measuring zone, connected to a resistance bridge. An external commercially available thermostat is used to keep the bath inner temperature closer to the desired one. The paper describes the bath and the temperature control system. Data acquired during the characterization of the bath are reported.
P.P.M. Steur, R. Dematteis
Comparison of the ITS-90 at 933,473 K and 1234,93 K / Report on IMGC measurements for Euromet 820
IMGC Rapporto Interno S/342.
EUROMET project No. 820 has been put in being as the regional complementary of the CIPM key comparison K4 for Long-stem Standard Platinum Resistance Thermometers, at the freezing points of aluminium (Al) and silver (Ag). The project is piloted by PTB (DE) with the K4 participants INM (FR), IMGC (IT), NMi/VSL (NL) and NPL (GB) as sub-pilots in so many loops. In contrast to the CIPM comparison, it was decided initially to circulate only thermometers to alleviate the burden of making available and circulating Al and Ag cells for each loop of the comparison, but after long discussions only one silver cell (provided by NMi, The Netherlands) was made to circulate and only among the sub-pilots, as a check on the stability of the high temperature standard platinum resistance thermometers (HTSPRTs). In each loop circulate two of these thermometers, to be measured at the silver point, and one normal SPRT, to be measured at the aluminium point. This report presents the results obtained at IMGC.