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Blackbody and other Calibration Sources, in Radiometric Temperature Measurements Part I Fundamentals
(2009)
Thermal transport in diamond
(2001)
High-temperature measurement techniques for the application in photometry radiometry and thermometry
(2009)
Strahlungsthermometrie
(2014)
Strahlungsthermometrie
(2006)
Thermodynamic temperature determinations of Co-C, Pd-C Pt-C and Ru-C eutectic fixed-points cells
(2006)
Quantitative thermal imaging of current densities and heat flow in electronic microstructures
(1996)
thermal diffusivity measurements by the laser flash method in the temperature range
from 23 °C to 3000 °C. The main objective was to assess the variability and coherency
of thermal diffusivity measurements performed at ultra-high temperatures at
the European level. Three refractory materials (molybdenum, tungsten and isotropic
graphite IG210) were selected for this inter-laboratory comparison, due to their high
melting point. The disk-shaped specimens needed were machined from the same
blocks of materials in order to reduce any potential scattering of results between
participants due to inhomogeneity effects.
The homogeneity of the sets of specimens was studied by the pilot laboratory (LNE)
before launching the comparison process. Thermal diffusivity measurements were
then carried out by the seven participants on the three materials during two successive
thermal cycles up to the maximum temperatures that can be reached by the
devices used. The analysis of results showed a good agreement between the participants
for temperatures above 400 °C, with relative deviations within the uncertainties
of measurement and lower than ± 4 % for molybdenum, ± 5 % for isotropic
graphite and ± 9 % for tungsten.
New PTB Set-up for the absolute calibration of the spectral responsivity of radiation thermometers
(2009)
Calibration and interpolation of the spectral responsivity of silicon photodiode based detectors
(2009)
Submicrosecond range surface heating and temperature measurement for efficient sensor reactivation
(2001)
A non-contact technique providing improved accuracy in area measurements of radiometric apertures
(2000)
Local variation of room temperature thermal conductivity in high quality polycrystalline diamond
(1998)
The influence of thermal barriers on heat flow in high quality chemical vapour deposited diamond
(1998)
An improved apparatus for measuring the spectral directional emissivity in the wavelength range between 1 µm and 20 µm at temperatures up to 2400 K is presented in this paper. As a heating unit an inductor is used to warm up the specimen, as well as the blackbody reference to the specified temperatures. The heating unit is placed in a double-walled vacuum vessel. A defined temperature, as well as a homogenous temperature distribution of the whole surrounding is ensured by a heat transfer fluid flowing through the gap of the double-walled vessel. Additionally, the surrounding is coated with a high-emitting paint and serves as blackbody-like surrounding to ensure defined boundary conditions. For measuring the spectral directional emissivity at different emission angles, a movable mirror is installed in front of the specimen, which can be adjusted by a rotatable arrangement guiding the emitted radiation into the attached FTIR-spectrometer. The setup of the emissivity measurement apparatus (EMMA) and the measurement procedure are introduced, and the derived measurement results are presented. For evaluating the apparatus, measurements were performed on different materials. The determined emissivities agree well with values published in literature within the derived relative uncertainties below 4% for most wavelengths.
Development of Long Wavelength Infrared Radiation Thermometry for Measurements in Gas Turbines
(2016)
Novel fixed point cell design for simultaneous contact and non-contact temperature measurement
(2005)
A lens-free InGaAs transfer radiation thermometer with an extended calibration range above 960 °C
(2005)
Complete characterisation of thermal heat transfer in high quality chemical vapour deposited diamond
(1999)
For several years Physikalisch‐Technische Bundesanstalt (PTB) has performed thermodynamic temperature measurements on a large area blackbody applying filter radiometers (FR) based on silicon photodiodes and interference filters with center wavelengths at 676 nm, 800 nm, 900 nm, and 1000 nm. These FRs were used for the determination of possible systematic deviations of temperatures measured according to the International Temperature Scale of 1990 (ITS‐90), T90, and the thermodynamic temperatures T. The measurements in 1995 with the 676‐nm‐FR and the 800‐nm‐FR revealed a difference of 50 mK of T−T90 at temperatures around the freezing point of silver (961.78 °C). The observed difference decreases with decreasing temperatures, indicating that it may be attributed to a systematic deviation in the ITS‐90 from T due to the gas thermometric temperature measurement at 457 °C, which has …
Room temperature microscopic thermal transfer in a high quality chemical vapor deposited diamond sample is completely characterized with micrometer resolution. A thermoreflectance microscope measures thermal conductivity and its slight variations inside a grain. Measurements reveal an inhomogeneous conductivity distribution with highest values close to that of natural IIa diamond. Using the same microscope, frequency dependent investigations of thermal barriers located between diamond grains are performed. Thermal resistance is found to vary between 10−9 and 10−8 m2K/W. Frequency dependent measurements sensitive to three-dimensional heat flow and averaging over a variable number of grains yield an enormous decrease of thermal conductivity with decreasing modulation frequency. Taking the average of thermal conductivity inside the grains and an average value for the barrier height together …
In the proposed scheme temperatures are defined by interpolation and extrapolation with respect to two reference fixed points (n=2), with assigned temperatures. The definition includes one full‐range and two sub‐ranges in temperature. The scheme in question will be compared with two alternatives referred to (1) as n=1, using one reference point only, as in the ITS‐90, and (2) as n=0, involving direct measurement of the thermodynamic temperature by means of absolute radiometry.
A comparison of high temperature fixed-points of Pt-C and Re-C constructed by BIPM, NMIJ and NPL
(2005)
Recently the CEN/TC 205/WG 12 Clinical Thermometer has finalised the European standard on clinical thermometers, EN 12470, by implementing the part 5 Clinical thermometers—Performance of infra-red ear thermometers (with maximum device). This last part of the EN 12470 series is dealing with the performance and requirements for infrared ear thermometers. The other four parts are dealing with metallic liquid-in-glass thermometers, phase change-type (dot matrix) thermometers, compact electrical thermometers (non-predictive and predictive), and electrical thermometers for continuous measurement.
Beside this European standard there are national standards dealing with clinical thermometers, the most important in the USA and in Japan. In the field of legal metrology there are three OIML recommendations on clinical thermometers, covering the field of mercury-in-glass thermometers (R7), electrical thermometers for continuous measurements (R114), and electrical thermometers with maximum device (R 115).
A chemical semiconductor sensor for oxygen gas was activated by thermal treatment. The thin Pt layer of the n-Si/SiO2/Si3N4/LaF3/Pt field effect structure was used as the gate electrode for sensitivity measurements, heating resistance and temperature sensor. Taking advantage of using the gate electrode for heating only the sensitive two layer system LaF3/Pt (thickness only 300 nm) has to be at high temperature. The reactivation was shown to be a very fast process. Within a period of 10µs the structure was heated and the activation process was completed. The temperature measurement was done using the voltage drop at the gate and the current of the heating impulse. For the temperature measurement a resolution on the time scale of nanoseconds was achieved. The time dependent temperature distribution in the sensor multi layer structure was simulated using the CFD-ACE+ software of CFDRC. For the µs-impulses the temperature increase of only the thin layers and not the silicon bulk was shown.
Radiator standards for accurate IR calibrations in remote sensing based on heatpipe blackbodies
(1999)
The demand of instrumentation in the field of remote sensing is increasing rapidly. For international compatibility, for reliable results and precise long-term investigation, necessary for example in the measurement of climatic trends, accurate traceability of the results to international standards or SI-units is mandatory. Additionally, interpretation of the results strongly requires a careful evaluation of the involved errors and the resulting uncertainties in order to allow for a rating of the obtained results. For that purpose quality assurance was introduced, not only for industrial fabrication, but also, and with increasing tendency, for industrial and scientific research. As an overview, the necessity and the possibilities of quality assurance in the area of remote sensing are discussed. Taking remote sensing of temperature as an example, the general approach is described. For that purpose, a description of heatpipe blackbodies …
An experimental facility is presented, which allows calibration and detailed investigation of infrared camera systems. Various blackbodies operating in the temperature range from -60 degree(s)C up to 3000 degree(s)C serve as standard radiation sources, enabling calibration of camera systems in a wide temperature and spectral range with highest accuracy. Quantitative results and precise long-term investigations, especially in detecting climatic trends, require accurate traceability to the International Temperature Scale of 1990 (ITS-90). For the used blackbodies the traceability to ITS- 90 is either realized by standard platinum resistance thermometers (in the temperature range below 962 degree(s)C) or by absolute and relative radiometry (in the temperature range above 962 degree(s)C). This traceability is fundamental for implementation of quality assurance systems and realization of different standardizations, for …
Above the freezing point of silver (961.78 °C), the International Temperature Scale of 1990 is defined in terms of Planck’s radiation law. The scale is maintained and disseminated using a validated and linear pyrometer in conjunction with a blackbody reference source at either the Ag, Au (1064.18 °C) or Cu (1084.62 °C) freezing point. In order to realize the scale with the highest precision high quality, well‐characterised, reproducible fixed‐point blackbody sources are required. Such sources have been maintained at NPL for a number of years, but it was felt that improvements to the design would be beneficial. A new Ag point blackbody source has therefore been constructed. The new design will improve the quality and reproducibility of the melting and freezing plateaux and reduce errors due to the ‘out‐of‐focus’ size‐of‐source effect which is difficult to measure and to eliminate. Full details of the design of the new …
HIMERT
(2003)
Metal‐carbon eutectic mixtures show much promise for high‐temperature standards applications. A research project, Novel, High temperature, Metal‐carbon Eutectic fixed points for Radiation Thermometry, Radiometry and Thermocouples (HIMERT) was accepted by the European Union (submitted under the Framework 5 Growth Programme) with a view to developing a unified European approach to these standards. The objectives of the project are to develop fixed‐point cells both for radiation thermometry/radiometry and contact thermometry calibration applications. In total three sets of cells will be developed, two for radiation thermometry (by BNM‐INM and NPL) and one for contact sensors (by BNM‐LNE) and comparisons performed of the differing crucible designs. The cells developed for radiation thermometry will be calibrated according to the ITS‐90 and measured radiometrically by a third participant (PTB …
The Physikalisch-Technische Bundesanstalt (PTB) has developed dedicated instrumentations and methods for the traceable calibration of space borne instruments in terms of the three fundamental radiometric units, i.e. spectral radiance (radiation temperature), spectral radiant intensity and spectral photon flux. The traceable calibration under conditions similar to the space environment is achieved by use of two major radiometric calibration facilities of PTB, the Spectral Radiance Comparator Facility (SRCF) and the Reduced Background Calibration Facility (RBCF) which are part of the Primary Temperature Radiator Facility of PTB and cover the wavelength range from the UV to the FIR (THz range). The improved detector instrumentations of the SRCF and RBCF, detailed calibration schemes and results of calibrations for space missions are presented.
Gas sensors based on a semiconductor-supported LaF3/Pt-structure require regular re-activation by thermal treatment. A convenient way to accomplish this is by applying an electrical current pulse to the Pt-electrode and controlling re-activation by the amount of Joule heat deposited. Pulse length has to be chosen to balance the requirements of thermal energy needed for re-activation and the constraints in peak thermal power to prevent damage. Prerequisite to optimization is a knowledge of the thermal response of the complicated thin film sensor system consisting of several layers with unknown thermal properties. Modulated photothermal microscopy was used to detect inhomogenities in thin film heating and early stages of failure under thermal load. It was found that the formation of gas bubbles in the film is one of the major sources of failure. These measurements were complemented by measurements of …
The thermodynamic temperatures of the phase transition of Re-C, TiC-C, and ZrC-C eutectic fixed-point cells have been measured for the first time using different filter radiometers in irradiance mode. The spectral responsivity of these filter radiometers was measured traceable to the primary detector standard of the PTB, a laser based cryogenic radiometer. The relative extended uncertainties of the spectral responsivities of the filter radiometers in the irradiance mode were in the range from 5· 10-4 up to 2.5· 10-3. The measurements have been performed at the high temperature calibration facilities of the VNIIOFI and the PTB with eutectic fixed-point cells manufactured by VNIIOFI.
The intercomparison of radiation temperature scales between PTB and NMIJ was carried out in September 2001. PTB sent their radiation thermometer LP3 to Japan and NMIJ made the comparison between the LP3 and NMIJs Topcon radiation thermometers with a comparison blackbody from 1000/spl deg/C to 2500/spl deg/C. Both scales agreed within /spl plusmn/0.8/spl deg/C in the whole range.
The large area double-heatpipe blackbody (LABB) used for comparing thermodynamic temperatures with the International Temperature Scale of 1990 (ITS-90) at temperatures higher than 600 C is based on two sodium heat pipes. The lowest temperature at which the sodium heat pipes work properly is strongly correlated to the onset of sodium evaporation. This is expected for temperatures well above 500 C. Planning to use the LABB for extending the comparison of thermodynamic temperatures with the ITS-90 to temperatures as low as possible, we measured the isothermal behaviour of the blackbody cavity starting at heatpipe temperatures of 400 C. The temperature of the cylindrical part of the cavity was measured with a standard platinum resistance thermometer (SPRT) sensing the bottom of the cavity and up to three quarter of the cylindrical part of the cavity. The obtained temperature profiles are well explained assuming the occurrence of two superimposing effects: a real nonisothermal behaviour of the LABB for temperatures below 500 C and a cooling of the SPRT caused by radiation loss through the aperture of the cavity. Applying a Monte-Carlo simulation we calculated the emissivity of the LABB at different heatpipe temperatures below 600 C using the obtained non-isothermal temperature distribution at the cylindrical walls. It was found that even at temperatures as low as 415 C the accuracy of the LABB is sufficient for comparison of thermodynamic temperatures and the ITS-90.
For the sake of ensuring improved accuracy and traceability for temperature measurements above the copper point (1084 OC), four laboratories are joining their efforts in developing high-temperature fixed points based on eutectic transitions of metal-carbon mixtures [1]. These phase transitions, on the basis of radiation thermometry results presented thus far [2, 3], encouraged the participants to work towards two eventual applications: hightemperature fixed—point calibration sources for radiation thermometry, and fixed points for the calibration of contact thermometers, including Pt/Pd, Pt/Rh and W/Re thermocouples.
Here will be given the up-to—date works accomplished within or in relation with this project in the participating laboratories. The perspectives of this work are wide and should allow the usage of such fixed points at temperatures ranging from 1150 C to 2700 C. The remaining uncertainty concerns the …
An advanced method for the calibration of tungsten strip lamps is reviewed in detail. The method is based on measuring the ratio of the spectral radiances of two sources at different radiance temperatures TL by radiation thermometry. Instead of using the distribution temperature and the colour emissivity for the calculation of the radiance temperature, the derivative dTL/dλ in the vicinity of the effective wavelength of the detection system is applied. In a first step high-stability vacuum tungsten strip lamps are calibrated as first-order working standards with respect to fixed points of the International Temperature Scale of 1990 (ITS-90). In a subsequent step, secondary working standards are calibrated relative to these first order working standards with light of different wavelengths determined by interference filters. A detailed description of the evaluation procedure for the determination of the radiance temperature of the lamps is given and several problems encountered in operating the lamps are discussed. The standard uncertainties of the radiance temperature are below 0.2 K for the first order working standards.
The Physikalisch-Technische Bundesanstalt (PTB) uses calibrated filter radiometers to measure the thermodynamic temperature of blackbodies applied for the realisation and dissemination of the spectral radiance and spectral irradiance. This paper presents the PTB experience with the stability of the spectral responsivities of two different sets of filter radiometers, a set of four broad-band filter radiometers with centroid wavelengths in the visible spectral range (437 nm, 510 nm, 558 nm and 728 nm), using a combination of coloured glass filters as wavelength selective elements and a set of five narrow-band interference filter radiometers with centroid wavelengths in the visible and in the near infrared wavelength range (676 nm, 802 nm, 903 nm and 1003 nm). The time period of their continuous investigation with respect to the relevant stability parameters, the integrated spectral responsivity and the centroid wavelength, is about seven years for the broad-band filter radiometers and up to ten years for the narrow-band interference filter radiometers. Both types of filter radiometers show sufficient stability for their application as high-accuracy temperature measurement instruments. Relative changes in the integrated spectral responsivity up to some parts in 103 and for the interference filter radiometers a linear increase of the centroid wavelength with time in the order of several ten picometers per year have been observed. A comparison between the two types of filter radiometers is given, with respect to the contribution of the stability of these parameters to the uncertainty budget of thermodynamic temperature determination. Reasons for the observed …
Blackbody radiators provide calculable spectral radiance and irradiance if their temperature and their emissivity is well known. Due to technical restrictions, one single blackbody can cover only a limited temperature range and therefore limited wavelengths for spectral radiance and irradiance calibrations. Space borne instruments for measuring the solar emission usually need calibrations from the UV to the near Infrared part of the optical spectrum [1] whereas remote sensing experiments for measuring earth surface temperatures for climate prediction or spaceborne instruments that deliver evidence for water on the surface of planet Mars [2] require calibration in the far infrared spectral range. To achieve these complementary requirements, PTB has set-up a series of blackbody based instrumentations, which are combined in the Primary Temperature Radiator facility (PriTeRa). To cover the whole wavelength range from 200 nm up to 800 µm different blackbody designs have to be applied.
In order to assess the performance and capability as well as the reproducibility of cell production five different Metal-carbon (MC) eutectic cells from three institutes were measured by radiation thermometry at PTB. The reproducibility of the melting temperature approached the requirements set by CCT/CCPR but significant differences were seen between different manufactures.
The intercomparison of radiation temperature scales between PTB and NMIJ was carried out in September 2001. PTB sent their radiation thermometer LP3 to Japan and NMIJ made the comparison between the LP3 and NMIJ's Topcon radiation thermometers with a comparison blackbody from 1000 C to 2500 C. Both scales agreed within+ 0.8 C in the whole range.
A collection of slides from the author's conference presentation is given. The presentation introduces the infrared-optical characterization of thermal barrier coatings and the development of LWIR pyrometer for measuring temperature in an operating gas turbine. The test facility for evaluating the LWIR pyrometer is also presented. This presentation includes the experimental setup for LWIR calibration and measurement.
The intercomparison of radiation temperature scales between PTB and NMIJ was carried out in September 2001. PTB sent their radiation thermometer LP3 to Japan and NMIJ made the comparison between the LP3 and NMIJ’s Topcon radiation thermometers with a comparison blackbody from 1000 C to 2500 C. Both scales agreed within±0.8 C in the whole range.
Mittels der planaren laserinduzierten Fluoreszenz (PLIF) können im Brennraum eines Transparentmotors Messungen durchgeführt werden, die den Gemischbildungsprozess beim Wasserstoffmotor zweidimensional qualitativ darstellen. Auch quantitative Messungen und damit Aussagen über das Kraftstoff-Luft-Verhältnis im Brennraum sind möglich. Für diese Messungen wird ein Gasgemisch ans Helium und einer Tracersubstanz verwendet, und der Motor wird geschleppt. Bei Betrieb des Motors in der Teillast sind auch Messungen im gefeuerten Betrieb, d.h. mit Wasserstoff und zugesetzter Tracersubstanz, möglich. Durch direkte Messung des Kraftstoff-Luft-Verhältnisses und der Wasserstoffkonzentration am befeuerten Aggregat mit Hilfe der Raman-Spektroskopie konnte nachgewiesen werden, daß mittels PLIF der Einströmvorgang qualitativ und das Kraftstoff-Luft-Verhältnis quantitativ grundsätzlich richtig erfaßt werden. Qualitative und quantitative PLIF-Messungen sind prinzipiell nicht nur bei Wasserstoffmotoren, sondern auch bei Gasmotoren mit anderen Brenngasen denkbar. Allerdings sind noch weitere Arbeiten erforderlich, um den Quantifizierungsfehler deutlich abzusenken. Zukünftiges Verbesserungspotential für diese Meßtechnik besteht in verschiedenen Punkten. Dazu gehört die Optimierung und Anpassung der Mischstrecke zur Erzeugung des Gas-Luft-Gemisches mit definiertem Kraftstoff-Luft-Verhältnis an die jeweiligen Meßaufgaben, um den relativen Fehler des Lambda-Wertes noch weiter zu reduzieren. Eine Verringerung der Tracerkonzentration erscheint problemlos möglich. Um das Problem der Hintergrundfluoreszenz zu lösen, sind verschiedene Möglichkeiten denkbar, die noch genauer zu untersuchen sind.
Planar laser-induced fluorescence (PLIF) has been successfully used for the investigation of the mixture formation process in hydrogen engines for passenger cars. Detailed information has been obtained about process development (qualitative measurement) and on fuel/air-ratio (quantitative measurement) inside the combustion chamber. These results can be used for further optimization of mixture formation and combustion process concerning emissions and fuel consumption. The measurement technique used is not only limited to hydrogen or to passenger car engines, but can also be applied to other fuel gases like natural gas or to other engine sizes like bus engines. The main topic of this paper is the experimental verification of the procedure which was executed by simultaneous PLIF and Raman scattering measurements. By Raman scattering the fuel/air-ratio can directly be determined from direct concentration measurements of the different gas species. The fuel/air-ratios determined by PLIF and Raman measurements are in good agreement indicating that a quantitative fuel/air-ratio measurement during the mixture formation process of gas and hydrogen engines is possible by PLIF. This fact is also confirmed by other measurements, e.g., global fuel/air-ratio calculated from measured intake air and fuel gas flow.
The temperature of high voltage equipment is often the limiting factor when transmitting electrical energy because the electrical insulation can get severely aged when the temperature is exceeding a certain limit. Hence, cooling has to be improved or heat generation must be reduced to avoid damage of the insulation. In this paper a new method was examined by investigating electrically insulating phase change materials which are able to store latent heat during a phase change from the solid to liquid state in times of high energy demand. To verify the electrically insulating properties of paraffins, one class of phase change materials, a special test cell was designed allowing the determination of breakdown voltage of phase change materials. The measurements on one paraffin sample proved the promising electrical insulating properties and it was shown that the breakdown voltage in the liquid state is comparable …