RECENT ADVANCES IN NANOPARTICLE SIZE MEASUREMENT WITH A PARTICLE GROWTH SYSTEM COMBINED WITH AN OPTICAL-PARTICLE COUNTER - A FEASIBILITY STUDY

A particle growth system (PGS) of original design is presented here, w hich, when combined with an opticle particle counter has the same func tion as a condensation nucleus counter (CNC). After an experimental st udy validated by a numerical model of transfers in a continuous-flow c ondenser, a relationship of unambiguous dependence is established betw een the droplet sizes and the size of the primary particles when the l atter are between 4 and 20 nm. Furthermore, when aerosol sample is mad e up of an ultrafine fraction and a fine fraction (about 50 nm), the s ize distribution of the droplets obtained from the PGS is shown to be bimodal too. Finally, the activation efficiency of our PGS is found to be of the order of 100% for particles as small as 4 nm. Copyright (C) 1996 Elsevier Science Ltd