Characterization of atmospheric pressure plasmas by a Gerdien condenser

Abstract

A compact Gerdien condenser is being developed as a new characterization tool for laboratory-produced atmospheric pressure plasma. The Gerdien condenser is capable of determining the ion density and mobility, thus ion species composition of the plasma. The device has a 1.0 cm diameter, 6.0 cm long cylindrical current collector electrode mounted on a bias electrode of 1.7 cm inner diameter. The flow rate of the fan attached at the end of the condenser is set from 1.9 to 7.5 × 102 cm3 s-1. Some of the values of ion mobility calculated from the I - V characteristics obtained for atmospheric plasmas produced by RF excited atmospheric pressure plasma pen are in the range of O+, O-, O2-, O2+, Ar+, N+ and N2+. The total positive ion densities at 2.0 cm away from the plasma pen are determined to be in the range of 106 cm-3.