Nanometer Particle Detection by the Condensation Particle Counter UF-02proto

In this study we present a method for how to improve the particle detection efficiency of condensation particle counters. The recently developed swirling flow condensation particle counter UF-02proto was studied. Investigations show that at default regime (when the temperature difference between the saturator and the condenser is 32.5°C) an instrument background is 0.002 cm−3, a maximum measurable number concentration is 100000 cm−3, and an instrument cut-size D50 is 4.4 nm. Increasing the temperature difference, the homogeneous nucleation starts around the temperature difference of 39.0°C. Subsequent temperature difference increasing enhances the number concentration of the nucleated particles. However, the experimental results show that the nucleation process can be prevented using existing aerosol particles in the supersaturated region. For example, when the number concentration of 15 nm silver particles exceeds 4000 cm−3 then the homogeneous nucleation inside CPC disappears. The detection efficiency was investigated as a function of the temperature difference operating instrument in default and in nucleation regime. The lowest reliable instrument cut-size D50 was 1.8 ± 0.2 nm when the temperature difference exceeded 43.5°C.