PERFORMANCE OF VIENNA TYPE DIFFERENTIAL MOBILITY ANALYZER AT 1.2-20 NANOMETER

The transfer functions of the so called ''Vienna type'' differential m obility analyzer (DMA) were studied experimentally at the size range o f 1.2-20 nm following the procedure suggested by Stolzenburg (1988) Ph .D. Thesis. For the study, two identical DMAs were used as a tandem DM A (TDMA) arrangement to measure nanoparticIes from a hat wire WO, gene rator. The approximate analytical formulae by Stolzenburg describing d iffusion broadening of the DMA transfer function were observed to be v alid with high accuracy from 20 nm down to similar to 2 mm. In the siz e range of 1.2-2 nm nominal mobility equivalent diameter small deviati ons of the shape of the TDMA output signal predicted by Stolzenburg we re found. (C) 1997 American Association for Aerosol Research.