Ion Beam Probe Measurements of Electron Temperature

The technique for measuring electron temperature with an ion beam probe has been refined, the time resolution reduced and the limitations evaluated. The technique involves sequentially probing the same volume of plasma with beams of different ions species and using the observed secondary ion currents and the known ionizing cross sections to evaluate the electron temperature. Detailed measurements have been made on a hollow cathode discharge and the results compared with Langmuir probe and spectroscopic data. Quantitative results can only be obtained with K + -Na + beams due to the lack of cross sections for other ion species. Theoretical cross sections provide qualitative indications of the system behaviour but are not sufficiently accurate to permit quantitative data reduction.