Effect of Operation Pressure on the Response of ePNC Particle Number Concentration Sensor

Abstract

In this article we present a method that aims towards more ideal number concentration response of a diffusion charger and diffusion collectorbased particle sensor (Dekati ePNC) by utilizing reduced pressure conditions in the sensor. A model is derived for the charger and diffusion collector stage of the sensor as well as for the total particle number concentration response. The derived model is validated with experimental characterization measurements in different operation pressures. The experimental results show that reduced operation pressure makes the sensor response less dependent on particle size, approaching pure particle number response. The obtained results improve the feasibility of the diffusion-charging based method in the measurement of particle number concentration.