Charge-Carrier Mobilities in Liquid Helium at the Vapor Pressure

Accurate values of the mobility of positive- and negative-charge carriers in liquid helium are presented. The measurements were carried out at the vapor pressure, over a temperature range of $0.28°\mathrm{K}<T<\mathrm{}5.18\mathrm{}°\mathrm{K}$ for negative-charge and $0.37°\mathrm{K}<T<\mathrm{}5.18\mathrm{}°\mathrm{K}$ for positive-charge carriers. A detailed description is given of the experimental techniques and of possible sources of error.