Probe measurement of an ECR hydrogen plasma facing the C12A7 electride surface

Abstract

Abstract Plasma parameters of an ECR discharge excited in a compact ion source with a replaceable plasma electrode (PE) were measured with a Langmuir probe. The PE was installed to investigate how an electride PE changes the plasma parameters from those with a Mo PE. The effect upon the plasma parameters in front of the PE due to the material will be elucidated by changing the probe position axially along the beam extraction direction. Analyses of the measured probe characteristics revealed that electride PE has a higher electron density (ne) and lower electron temperature (Te) than the Mo PE. When the PE was biased negatively, the ratio of the positive saturation current (Ii ) to the negative saturation current (Ie +Ih- ) for the electride PE was about 1.6 times of the ratio for the Mo PE.