Evaluation of a Recording Continuous Cloud Nucleus Counter

Abstract

For certain field and laboratory investigations, it would he useful to have apparatus capable of yielding a continuous, instantaneously recorded measurement of the concentration of cloud nuclei. A description of such a device is given, in which some of the problems of static diffusion chambers have, been mitigated. It is shown that clear plateaus exist in the deduced cloud nucleus concentration when plotted against the time the sample spends in the chamber, or against size of droplets detected, or sample flow rate. Transient supersaturations have been eliminated and the sample has been confined to a zone of precisely known supersaturation. It is shown that depletion of supersaturation by growing droplets does not occur for count rates as high as 1500 nuclei sec⁻¹.