Design and Analysis of a Retarding Potential Analyzer to Be Used for BURFIT-80 RF Ion Thruster Plume Diagnostics
by Mert Satir, Murat Celik

Diagnostics of the plume plasma of electric thrusters such as ion engines and Hall thrusters used as in-space propulsion systems for satellites, provides important information about the underlying physics of the thruster operation and insight about possible thruster plume interaction with satellite operations and particle impingement on sensitive satellite surfaces. In order to determine the effects and hazards of the plume on satellite, and to examine the performance of the thruster, characterization of the plume plasma is important. Among various types of diagnostic instruments, Retarding Potential Analyzer (RPA) is a powerful one that is used for measuring the ion energy distribution of the plume plasma. The RPA data provides data about the thrust level and factors affecting the lifetime of the plasma thruster. In this study, design, material selection and manufacturing of a small ( 10mm diameter) RPA to be used for an RF ion engine plume plasma diagnostics are explained. The proposed RPA will have three grids. First one is a floating grid used for reducing the plasma perturbation. The second grid is negatively biased for repelling the electrons. The third grid is the ion-retarding grid which is positively biased by sweeping the potential between 0 to 1100 Volts.