Multipole resonance probe measurement in plasma

Abstract

In the study of low-temperature plasma, the plasma parameters such as plasma density and plasma temperature are required. Recently, a multipole resonance probe (MRP) which utilized an active plasma resonance concept was proposed. The probe consists of two hemispheres, insulated by a thin dielectric sheet. The advantages of the probe include simple setup and localized measurements similar to those of the conventional Langmuir probe. The probe does not cause plasma contamination, one of the Langmuir probe disadvantages since the probe conductors are covered in the dielectric. However, it can only determine plasma density. The MRP is usually connected with a Network Analyzer for measuring the reflection coefficient spectrum which can be analyzed to obtain the plasma density. In this experiment, the constructed MRP is used to measure the plasma density comparing to the Langmuir probe. The results of the experiment showed that the plasma density result of the MRP gives a similar tendency as that of the Langmuir probe. However, the plasma density determined by the MRP was deviated when compared with the Langmuir probe. In order to explore the idea that MRP does not need to be constructed in hemisphere shape, MRP in different shapes have been assembled and verified.