Vapor Pressure ofHe3-He4Solutions

Abstract

Measurements have been made of the vapor pressures of solutions of ${\mathrm{He}}^3$ in ${\mathrm{He}}^4$ having molar ${\mathrm{He}}^3$ concentrations 1.91, 3.34, 6.51, and 12.04% in the temperature range 1.4°K to 2.6°K. The measurements involved the observation of the excess pressure of the solution over that of pure liquid ${\mathrm{He}}^4$ which was carefully maintained at the same temperature as the solution using an apparatus which ensured high precision of pressure transmission between the low- and high-temperature parts of the apparatus, especially for liquid ${\mathrm{He}}^4$ temperatures above the lambda temperature. The results are compared with previous evaluations and comparisons made with recent theories of ${\mathrm{He}}^3$—${\mathrm{He}}^4$ solutions.