A Standardized Interpolation of Temperature Using Rhodium-Iron Resistance Thermometers Over the Interval 4.2 K to 24.5 K

作者：Tew, W. L.^*; Ru**y, R. L.; Lin, P.; Lipinski, L.; Steur, P. P. M.; Ricketson, B. W. A.

来源：International Journal of Thermophysics, 2015, 36(8): 2036-2059.

DOI：10.1007/s10765-015-1877-4

• Interpolation
• Low temperature
• Rhodium-iron resistance thermometers
• Thermometry

The worldwide history and present state of development of rhodium-iron resistance thermometers (RIRTs) is briefly reviewed. A standardized interpolation method using RIRTs with the nominal composition of 0.5 % Fe (by mole) is presented, with examples using data taken from 60 RIRTs made from a variety of wire batches and sources worldwide over the last 40 years. The parameterization exploits the favorable characteristics of the Cragoe reduced resistance Z(tau) and a suitably reduced temperature tau. A reference function Z(ref)(tau) which approximates the average characteristics of selected wire is derived for use over the interval 0.65 K to 24.5561 K on the ITS-90. The deviations of real RIRT data from this reference function are examined, and simple four-parameter Fourier-series solutions for the resulting deviation curves are presented. Despite the fact that the wire samples may be of different origins or state-of-anneal, it was found that the interpolations are successful for most of the samples studied over the 4.2 K to 24.5561 K interval, at the level of 1 standard uncertainty or less. This method would allow for calibrations of most RIRTs over this interval using only six calibration points, permitting an efficiency not achievable using the common least-squares curve-fitting calibration methods. The potential of this formalism for a standardized interpolation scheme using RIRTs is discussed.

• 出版日期2015-8
• 单位中国科学院理化技术研究所