Primary state standard of the temperature in the range from 0 to 3200 °С, GET 34-2020: practical implementation of the new definition of kelvin

Abstract

The article considers the necessity of ways of modernization the Primary standard of the temperature GET 34-2007. Special attention is paid to the transition to a new definition of kelvin. Taking into account that the new definition of kelvin does not directly affect the status of the current international temperature scales ITS-90 and PLTS-2000, but there are significant advantages for measuring thermodynamic temperatures below 20 K and above ~1300 K, the main focus of the modernization of the GET 34-2007 in the range from 273.15 K to 1235 K was focused on improving the methods and means of implementing the International Temperature Scale ITS-90. As part of the modernization of the Primary standard in the range above 1235 K, a set of equipment has been created that allows the reproduction of kelvin in accordance with its new definition by two methods recommended by the Consultative Committee: the method of absolute primary radiometric thermometry and the method of relative primary radiometric thermometry. The basic principles of the implementation of these methods, composition and metrological characteristics of the Primary standard are described. The results of key comparisons of the developed standard in the range from 273.16 K to 692.477 K and the results of temperature measurements of a number of high-temperature fixed points and a comparison of the results with the published results of leading national metrological institutes are presented.