Institute of Fluid-Flow Machinery
Polish Academy of Sciences

Abstract

The probe developed consists of two concentric metal spheres, the inner of which is a collector and the outer serves as a shield. Two circular openings are made on opposite sides in the outer sphere. Through these openings an airborne particle can flow into the internal zone of the probe. The charged single particle induces a measuring signal on the inner electrode, before it is finally discharged after impacting on the electrode. The amplitude of the generated voltage signal depends almost uniquely on the particle charge. The method presented in the paper is capable of measuring the charge on aerosol particles down to 3 ⋅ 10^–14C with an accuracy of about ±5%.