Entropy of the Superfluid Component of Helium

Abstract

The specific entropy deficit $\ensuremath{\Delta}s=s\ensuremath{-}{s}_{s}$ of the superfluid component of liquid helium II has been determined over the temperature range 1.27\ifmmode^\circ\else\textdegree\fi{}K to 1.93\ifmmode^\circ\else\textdegree\fi{}K. Here $s$ and ${s}_{s}$ are the specific entropy of the bulk liquid and of the superfluid component, respectively. Superfluid was transferred into a thermally isolated reservoir from a constant temperature reservoir by film flow. Values of $\ensuremath{\Delta}s$ were determined from flow rates obtained by driving the film by thermal means. Flow rates were measured with a capacitor death gauge. The present results indicate that $\ensuremath{\Delta}s=s$ within \ifmmode\pm\else\textpm\fi{} 3%.