scholarly journals Redefinition of Kelvin and the Present Status and Future Prospects of the International Temperature Scale at Low Temperature

2021 ◽  
Vol 56 (1) ◽  
pp. 3-11
Author(s):  
Takeshi SHIMAZAKI
Keyword(s):  
Low Temperature ◽  
Present Status ◽  
Temperature Scale ◽  
Future Prospects ◽  
International Temperature Scale ◽  
International Temperature

THE CALIBRATION OF PLATINUM RESISTANCE THERMOMETERS IN THE TEMPERATURE RANGE 11° TO 90°K

1951 ◽  
Vol 29 (2) ◽  
pp. 142-150 ◽  
Author(s):  
J. M. Los ◽  
J. A. Morrison
Keyword(s):  
Low Temperature ◽  
Temperature Scale ◽  
Platinum Resistance ◽  
National Bureau ◽  
International Temperature Scale ◽  
International Temperature ◽  
Platinum Resistance Thermometers ◽  
Resistance Thermometers ◽  
Corrective Term ◽  
Low Temperature Calorimetry

A set of six platinum resistance thermometers of a form suitable for low temperature calorimetry has been made and calibrated in the region 11° to 90°K. by intercomparison with a similar thermometer which had been calibrated at the National Bureau of Standards. Above 90°K. calibration has been made on the International Temperature Scale.Using the intercomparison data, it has been possible to derive a method whereby for these thermometers the scale for the region 20° to 90°K. may be found to within 0.002°C. by means of fixed points. The method applies a 'Z function' of the type used at the National Bureau of Standards (13), plus a corrective term which depends upon the resistance of the thermometer at the boiling point of hydrogen and upon the normal constants which are determined for the International Temperature Scale above 90°K.

ACCURACY OF OPTICAL PYROMETRY IN THE RANGE 800 °C TO 4000 °C

1958 ◽  
Vol 36 (10) ◽  
pp. 1397-1408 ◽  
Author(s):  
D. R. Lovejoy
Keyword(s):  
Standard Deviation ◽  
Temperature Scale ◽  
Primary Standard ◽  
Secondary Standard ◽  
Optical Pyrometer ◽  
Optical Pyrometry ◽  
International Temperature Scale ◽  
International Temperature ◽  
Carbon Arc ◽  
Temperature Standard

A pair of secondary standard tungsten strip lamps have had a luminance temperature – current calibration, in the range 800 °C to 2200 °C, at a number of national laboratories. An analysis of the calibration results confirms estimates of the accuracy of optical pyrometry in the range 800 °C to 2200 °C and supports the extension of these estimates to 4000 °C. The standard deviation uncertainty of optical pyrometry is shown to be about 1 °C at 800 °C rising to 2 °C at 2200 °C and 10 °C at 4000 °C, being about double this for the calibration of commercial pyrometers unless certain described precautions are taken.The reliability of the secondary standard lamps, when used under well-defined conditions, is confirmed and it is shown that they have a standard deviation calibration uncertainty of about 1 °C for the vacuum-type lamps in the range 800 °C to 1500 °C and 2 °C for the gas-filled lamps in the range 1500 °C to 2200 °C. Most of this uncertainty is due to primary standard optical pyrometer calibration errors. Attention is drawn to the fact that a carbon arc fulfills the requirements of a secondary luminance temperature standard at about 3514 °C.Recent determinations of the gold point and the second radiation constant indicate that the 1948 International Temperature Scale is lower than the thermodynamic scale by an amount varying from 0.8 °C at 800 °C to 12 °C at 4000 °C. This is already greater than the calibration errors of optical pyrometry and, in view of the still greater accuracies presaged by photomultipliers, a revision of the International Temperature Scale is suggested.

scholarly journals A large-area blackbody for in-flight calibration of an infrared interferometer deployed on board a long-duration balloon for stratospheric research

2018 ◽  
Vol 11 (8) ◽  
pp. 4757-4762 ◽  
Author(s):  
Friedhelm Olschewski ◽  
Christian Monte ◽  
Albert Adibekyan ◽  
Max Reiniger ◽  
Berndt Gutschwager ◽  
...  
Keyword(s):  
Temperature Scale ◽  
Environmental Research ◽  
Large Area ◽  
Atmospheric Measurements ◽  
Calibration Source ◽  
Aperture Diameter ◽  
International Temperature Scale ◽  
International Temperature ◽  
Long Duration ◽  
Better Than

Abstract. The deployment of the imaging Fourier Transform Spectrometer GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) on board a long-duration balloon for stratospheric research requires a blackbody for in-flight calibration in order to provide traceability to the International Temperature Scale (ITS-90) to ensure comparability with the results of other experiments and over time. GLORIA, which has been deployed onboard various research aircraft such as the Russian M55 Geophysica or the German HALO in the past, shall also be used for detailed atmospheric measurements in the stratosphere up to 40 km altitude. The instrument uses a two-dimensional detector array and an imaging optics with a large aperture diameter of 36 mm and an opening angle of 4.07∘ × 4.07∘ for infrared limb observations. To overfill the field of view (FOV) of the instrument, a large-area blackbody radiation sources (125 mm × 125 mm) is required for in-flight calibration. In order to meet the requirements regarding the scientific goals of the GLORIA missions, the radiance temperature of the blackbody calibration source has to be determined to better than 100 mK and the spatial temperature uniformity shall be better than 150 mK. As electrical resources on board a stratospheric balloon are very limited, the latent heat of the phase change of a eutectic material is utilized for temperature stabilization of the calibration source, such that the blackbody has a constant temperature of about −32 ∘C corresponding to a typical temperature observed in the stratosphere. The Institute for Atmospheric and Environmental Research at the University of Wuppertal designed and manufactured a prototype of the large-area blackbody for in-flight calibration of an infrared interferometer deployed on board a long-duration balloon for stratospheric research. This newly developed calibration source was tested under lab conditions as well as in a climatic and environmental test chamber in order to verify its performance especially under flight conditions. At the PTB (Physikalisch-Technische Bundesanstalt), the German national metrology institute, the spatial radiance distribution of the blackbody was determined and traceability to the International Temperature Scale (ITS-90) has been assured. In this paper the design and performance of the balloon-borne blackbody (BBB) is presented.

scholarly journals The freezing point of platinum

1934 ◽  
Vol 146 (859) ◽  
pp. 792-817 ◽  
Keyword(s):  
Fixed Points ◽  
Temperature Scale ◽  
Freezing Point ◽  
High Standard ◽  
National Physical Laboratory ◽  
Basic Point ◽  
International Temperature Scale ◽  
International Temperature ◽  
Physical Laboratory ◽  
Pure Substances

The International Temperature Scale, which has been in force since 1927, is based on certain values assigned to the boiling and freezing points of pure substances and on specified means of interpolation between, or extrapolation beyond, these points. The highest basic point of the scale is the freezing point of gold, defined as 1063·0° C, while for extrapolation from this temperature use is made of the Wien law of radiation, with a certain value of the constant C 2 . Though any temperature above 1063° C is thus completely defined without reference to further fixed points, determinations of such points are of considerable value. In particular, they serve to indicate the degree of reproducibility of the scale by the various users of it, and, when well authenticated, to provide secondary standards for its realization. Of such fixed points the most important has been the freezing point of palladium (1555° C), but the latest developments in furnace technique and refractory materials should now enable the freezing point of platinum to be used with equal, if not greater, advantage. The qualities of platinum which render it especially valuable in this connection are as follows: its freedom from oxidation; its high standard of purity, for which a convenient electrical test is available; its high freezing point (about 1775° C) which approaches the important zone of temperature covered by the electric fighting industry These qualities also make the platinum point especially suitable as the basis for a standard of fight, as has been proposed by a number of experimenters. It is with the two objects indicated above that the National Physical Laboratory has undertaken an investigation concerning the freezing point of platinum the precise scope of which may be defined as follows:— (1) To determine the value of the freezing point in terms of the International Temperature Scale.

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