REPEATED NUCLEATION IN AN UNDERCOOLED ALUMINUM DROPLET

The theory of nucleation phenomena is most often described in terms of the average behavior of a very large number of individual, independen t nucleation events. The direct observation of these events is a techn ological challenge, particularly in the condensed phases. We present h ere a technique which has been used to observe the repeated nucleation of solid phase Al from the liquid in the same 80 mu m droplet. A tota l of 845 events were recorded under nearly identical conditions and a statistical analysis is presented. The observed nucleation rates indic ate that multiple nucleation mechanisms were active. The relationship between this method and the droplet population technique are discussed and bounds on the accuracy of this result are presented which are use ful for the design of future experiments.