Realization of the ITS-90 at IMGC in the range of long stem PRTS

Techniques are recommended for comparisons, at the highest levels of accuracy, of fixed-point cells of the defining fixed points, excluding the vapour-pressure points, of the ITS-90, which are used for contact thermometry. The authors are the members of Working Group 1 of the Consultative Committee for Thermometry (CCT) of the Comité International des Poids et Mesures, dealing with Defining Fixed Points and Interpolating Instruments underlying the realization of the ITS-90.

“…The extension of the re-entrant well of the inner container extends through the top of the outer container. For more details on Hg cells, see [7][8][9].…”

Section: Hg Pointmentioning

confidence: 99%

Section: Ga Pointmentioning

confidence: 99%

“…The resulting internal pressure would therefore depend on the furnace design and position of the temperature gradient. For more details on cells of these materials, see [7,9,12].…”

Section: Fixed Points From In To Agmentioning

confidence: 99%

Section: Fixed-point Cellsmentioning

confidence: 99%

Section: • Mercury and Galliummentioning

confidence: 99%

See 3 more Smart Citations

On the International Temperature Scale of 1990 (ITS-90). Part II: Recommended techniques for comparisons, at the highest level of accuracy, of fixed-point cells used for contact thermometry

Mangum¹,

Bloembergen²,

Chattle³

et al. 1999

New developments in standard thermometry at the IMGC

Marcarino¹,

Ricolfi²

1996

Recent findings in precision platinum resistance and radiation thermometry at the Istituto di Metrologia "G. Colonnetti" are described. Two issues concern high-temperature platinum resistance thermometers. The first is the use of gas-controlled heat pipes for comparing these thermometers and the development of a novel approach to improve temperature stability and uniformity. The second deals with observations made at the freezing point of silver which suggest that humidity may lead to electric leakage. In radiation thermometry the main recent achievement has been the use of a photodiode-array thermometer to realize the ITS-90 above the silver point. Relative to single-detector thermometers, this new thermometer offers several advantages that are related to its spectral characteristics. Another issue of importance is the size-of-source effect (SSE). Practical rules for minimizing SSE errors in interlaboratory comparisons are given.

Platinum versus palladium thermocouples: an emf-temperature reference function for the range 0 C to 1500 C

Burns¹,

Ripple²,

Battuello³

1998

We present an emf-temperature reference function for platinum versus palladium (Pt/Pd) thermocouples in air for the range 0 EC to 1500 EC. The reference function is based on the International Temperature Scale of 1990 (ITS-90) and has an expanded uncertainty (coverage factor of two) of less than the equivalent of 11 mK for temperatures up to 1050 EC and rising smoothly to approximately 0.3 K at 1500 EC. The reference function is based on a set of Pt/Pd thermocouples of exceptional stability and homogeneity constructed from Pt and Pd wire of very high purity (99.999% mass fraction and 99.997% mass fraction, respectively). Experimental results are presented on the thermoelectric stability of Pt/Pd thermocouples at high temperatures and on the calibration of Pt/Pd thermocouples based on this reference function.