The Vapor-Pressure Curve of Helium between 4.2°K and 4.8°K

Abstract

Measurements of the resistance of four Allen-Bradley carbon resistors in the liquid helium temperature range from 1.8° to 4.2°K and at the hydrogen triple point have been fitted to smooth calibration curves. When the resistance is measured at helium vapor pressures from 760 mm to 1350 mm, and the corresponding temperatures are obtained from the so-called "agreed" scale of Van Dijk and Shoenberg, the calibration points in this range do not lie on these calibration curves. This discrepancy and the fact that the vapor pressure-temperature relation above 4.2°K has not been determined since 1915 suggest that a redetermination of the vapor pressure-temperature relation above 760 mm is desirable.