A Method for Realizing the High-Temperature Fixed Points of the ITS-90 by Using a Single Liquid-Solid lnterface

Abstract

A method of the freezing-point realization, that has a single liquid-solid interface in the metal of the fixed-point cell, was applied for the high-temperature fixed points of the ITS-90. The freezing point of aluminum realized by this method was compared with that realized by the conventional method with two liquid-solid interfaces. The result shows that the difference in the freezing point between the two methods is small and the uncertainty of the realization of the proposed method is as small as the conventional one. lt was found that the calibration of the platinum resistance thermometer could be automatically performed using this method.