An absolute temperature scale from 4 °K to 20 °K determined from measurements with an acoustical thermometer

Abstract

At NBS an acoustical thermometer has been used to obtain values of temperature at every degree from 5 to 20 °K as a basis for a temperature scale. This scale has been compared with four other temperature scales in the region from 10 to 20 °K. Since the acoustical thermometer is an entirely new approach to precision thermometry in this range the comparison of its resulting scale with scales based upon gas thermometry from 12 to 20 °K is significant. Indications of inaccuracies in the equilibrium hydrogen vapor pressure scales, and also in the He4 vapor pressure scale, are presented.