Performance of Vienna type differential mobility analyzer at 1.2-20 nanometer

The transfer functions of the so called ''Vienna type'' differential mobility analyzer (DMA) were studied experimentally at the size range of 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 DMA (TDMA) arrangement to measure nanoparticIes from a hat wire WO, generator. The approximate analytical formulae by Stolzenburg describing diffusion broadening of the DMA transfer function were observed to be valid with high accuracy from 20 nm down to similar to 2 mm. In the size range of 1.2-2 nm nominal mobility equivalent diameter small deviations of the shape of the TDMA output signal predicted by Stolzenburg were found. (C) 1997 American Association for Aerosol Research.