The 1962 He3 Scale of Temperatures. I. New Vapor Pressure Comparisons1

Abstract

A comparison of He3 and He4 vapor pressures, (P3, P4), has been made in an apparatus designed to reduce the number and magnitude of corrections associated with the refluxing film in the He4 pressure sensing tube and the attached bulb. The critical pressure of He3 has been redetermined to be at 873.0 ±1.5 mm Hg at 0° C and standard gravity; the corresponding temperature as measured by a He4 thermometer is 3.3240±0.0018° K on the 1958 He4 scale. These (P3, P4) comparisons and the 1958 He4 scale are the basis of the 1962 He3 scale of temperatures derived and evaluated in the papers following this one.