A steady-state model for a low pressure, Cs-Ba diode
摘要
A steady‐state model of a low pressure Cs‐Ba discharge has been developed. It calculates the plasma density, electron temperature, Cs atoms densities and output voltage for uniform conditions across the discharge gap and neglecting radiation losses. The model predictions are in good agreement with experimental data for a low pressure Cs discharge. Also, comparisons of the model with experimental data for a Cs‐Ba diode validates the system of equations used and indicates that Ba does not affect the current transport characteristics. The calculated I‐V curves for the Cs‐Ba diode match well with the experimental data below the emission current; however, above the emission current the calculated currents are much lower. This difference occurs when the model incorporates normal Schottky emission instead of anomalous Schottky. The effect of this latter is determined from estimates of the effective changes in the emitter work function for agreement between the model and experiments at high discharge current in the Cs‐Ba diode. Results suggest that changes in the Cs pressure strongly affect the anomalous Schottky emission, while changes in the Ba pressure seem to have negligible effect.