Cluster growth in plasma

The size of the clusters produced in a plasma-discharge, hollow-cathode sou rce depends sensitively on the distance separating the cathode from a groun ded grid introduced into the source to intercept the plasma beam. On this e vidence it was derived that a crucial parameter for cluster growth in that source is the time interval during which particles anal plasma coexist. Inf act, an approximately linear correlation between cluster size and plasma in teraction rime is indicated by the experimental data, implying that up to a bout I ms the rate of cluster growth is constant. Monte Carlo calculations for particle coagulation in low-temperature plasma, predict reasonably well the size evolution but not the ionization of the clusters. (C)1999 Acta Me tallurgica Inc.