Helium ii Film Transport. I. The Role of Substrate

Liquid helium ii film transport from aluminum, silver, copper, nickel, nickel-silver, stainless steel, Pyrex, quartz, and Lucite beakers has been measured using a variation of a previously described electrical technique. The degree of reproducibility and background variation observed in separate experiments on the same or on similarly prepared specimens of the same material was studied in detail. Rates on machined metals were found to be considerably lower than would be expected from many previous reports. In fact, rates measured over all the aforementioned materials were so similar in magnitude and reproducibility that the background variations involved prevent the resolution of any systematic dependence on substrate material which might exist. This is consistent with the size of the helium-substrate interaction as calculated by Schiff for copper, silver, and glass.