Operation of the Airmodus A11 nano Condensation Nucleus Counter at variousinlet pressures and various operation temperatures, and design of a new inletsystem

摘要

Measuring sub-3 nm particles outside of controlled laboratory conditions isa challenging task, as many of the instruments are operated at their limitsand are subject to changing ambient conditions. In this study, we advance thecurrent understanding of the operation of the Airmodus A11 nano CondensationNucleus Counter (nCNC), which consists of an A10 Particle Size Magnifier(PSM) and an A20 Condensation Particle Counter (CPC). The effect of the inletline pressure on the measured particle concentration was measured, and twoseparate regions inside the A10, where supersaturation of working fluid cantake place, were identified. The possibility of varying the lower cut-offdiameter of the nCNC was investigated; by scanning the growth tubetemperature, the range of the lower cut-off was extended from 1–2.5 to1–6 nm. Here we present a new inlet system, which allows automatedmeasurement of the background concentration of homogeneously nucleateddroplets, minimizes the diffusion losses in the sampling line and is equippedwith an electrostatic filter to remove ions smaller than approximately4.5 nm. Finally, our view of the guidelines for the optimal use of theAirmodus nCNC is provided.