Computerized Langmuir Probe Measurements in a Capacitively Coupled RF Discharge

TL;DR

This paper presents an automated system for measuring plasma parameters in RF discharges using a compensated Langmuir probe with wavelet-based signal processing, enabling detailed plasma analysis in a metallic artifact cleaning reactor.

Contribution

It introduces a computerized measurement setup with wavelet-based de-noising for Langmuir probe data in RF plasma, improving accuracy and spatial profiling capabilities.

Findings

Electron density has a flat profile in the middle of the discharge.

Wavelet transforms effectively de-noise probe signals without distorting I-V characteristics.

The system enables precise plasma parameter measurements in RF discharge reactors.

Abstract

A system of automated computerized Langmuir probe measurements is used in order to determine the plasma parameters in a plasma reactor constructed for cleaning of metallic artifacts by RF discharge. A compensated probe insures the suppression of the RF interference. The probe data are collected using a commercial data acquisition unit connected to a portable computer. The raw data are processed using wavelet transforms techniques which assures the de-noising of the probe signal without distortion of the probe I-V characteristic. The first and second derivatives of the I-V characteristic are determined. The measurement of the electron density spatial distribution in the inter-electrode distance indicates a flat density profile in the middle region of the discharge.