High Resolution Dielectric Constant Measurements in Fluid Helium Near the Liquid-Gas Phase Transition.

The dielectric constant was obtained from capacitance measurements made with a ratio-transformer bridge which resolved changes in the dielectric constant of 1 part in 10 to the 8th power. A brief introduction to the thermodynamics of the critical region and the general theory of the dielectric constant is followed by a discussion of recent theories which predict that while the dielectric constant is finite at the critical point, the slope delta epsilon/delta tau will diverge. The data are then analyzed and no evidence of a change in the dielectric constant is found.