Thermometry in low temperatures

Temperature metrology plays a pivotal role in fundamental science and applied technologies. This article explores the evolution of low-temperature thermometry, paying special attention to the redefinition of the kelvin through the Boltzmann constant. The article outlines the historical and contemporary contributions of the Temperature Standards Laboratory at Institute of Low Temperature and Structure Research of PAN. The laboratory has been instrumental in developing precise calibration methods and participating in international comparisons. Additionally, the paper discusses the implementation of the ITS-90 scale and the use of fixed-point cells, as well as the laboratory’s involvement in European metrology initiatives. These efforts highlight the interdisciplinary nature of temperature measurement and its critical importance in various scientific and industrial fields.