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Particles Plus® Water-based Pulse CPC instruments use the Adiabatic expansion to achieve the nucleation and works with distilled water.
In 1888, John Aitken, found a way to detect and count invisible by optical methods, ultrafine particles by enlarging their nucleus via heterogeneous condensation of a supersaturated water vapor.
Nafion® membrane is used for the humidification of the environment inside the chamber. During the adiabatic process no heat is exchanged between the system and the environment.
The particle radius threshold at which a supersaturated vapor will condense onto its surface is given by the following formula.
Where γ is the surface tension and Vvap, is the molecular volume of the water.
PO is the vapor pressure above a flat surface of the condensing vapor and P is the actual vapor pressure. P/PO is the Saturation Ratio, S
Varying the degree of S changes the minimum enlarged particle size. S=Scritical,r
