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Title: Analysis of double-probe characteristics in low-frequency gas discharges and its improvement

The double-probe has been used successfully in radio-frequency discharges. However, in low-frequency discharges, the double-probe I-V curve is so much seriously distorted by the strong plasma potential fluctuations that the I-V curve may lead to a large estimate error of plasma parameters. To suppress the distortion, we investigate the double-probe characteristics in low-frequency gas discharge based on an equivalent circuit model, taking both the plasma sheath and probe circuit into account. We discovered that there are two primary interferences to the I-V curve distortion: the voltage fluctuation between two probe tips caused by the filter difference voltage and the current peak at the negative edge of the plasma potential. Consequently, we propose a modified passive filter to reduce the two types of interference simultaneously. Experiments are conducted in a glow-discharge plasma (f = 30 kHz) to test the performance of the improved double probe. The results show that the electron density error is reduced from more than 100% to less than 10%. The proposed improved method is also suitable in cases where intensive potential fluctuations exist.
Authors:
; ; ; ;  [1]
  1. School of Aerospace Science and Technology, Xidian University, Xi’an 710071 (China)
Publication Date:
OSTI Identifier:
22392314
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 86; Journal Issue: 1; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; CURRENTS; DIAGRAMS; ELECTRON DENSITY; EQUIVALENT CIRCUITS; ERRORS; FILTERS; FLUCTUATIONS; GLOW DISCHARGES; INTERFERENCE; KHZ RANGE 01-100; PEAKS; PERFORMANCE; PLASMA POTENTIAL; PLASMA SHEATH; POTENTIALS; PROBES; RADIOWAVE RADIATION