Measurement of the radio frequency admittance of a plane grid capacitor in a plasma

Abstract

The admittance of a plane grid capacitor immersed in an ion beam plasma has been measured, and the results are in general agreement with the kinetic theory of the admittance (Buckley 1968). With a steady bias potential applied to the grids, the results showed a deviation from the theoretical behaviour that is attributable to plasma depletion by the grids. The effect of varying the background pressure showed that electron-neutral collisions had a negligible effect on the measured admittance. A significant change in the admittance was found for a measuring voltage applied to the grids of the order of the electron temperature.