Electron Density Determination by Means of Tuneable 50 GHz and 150 GHz Interferometers

Abstract

The electron density is one of the most important parameters to characterise the properties of plasma. Among several other methods microwave interferometry is a well known technique. Two approaches at different fre-quencies are given to show the application of microwave interferometers to practical problems. An interferometer working at a frequency of 150 GHz is used to measure the electron density of an atmospheric pressure microwave torch and the time resolved electron densities in the vicinity of the electrode of commercial fluorescent lamps. A 50 GHz interferometer set up is used to measure the electron density in an inductive coupled plasma at low pressures. The parameters pressure and rf-power are varied. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.