Modelling the RF source in GDOES

Abstract

An equivalent model of an asymmetric radiofrequency (RF) powered glow discharge (GD) plasma is combined with an equivalent circuit of the stray cell capacitance, coaxial cable connection, matching box and power generator needed to drive it, to provide an electrical model of the impedance-matched RF source commonly used in GDOES. Component values in the matching circuit are determined in situ using procedures provided. The resulting model is then used to calculate plasma resistances based on the matching box settings. As a test of the model, these plasma resistances are then used as emission yield corrections in a multi-matrix calibration, and compared with the more familiar VDC corrections.