On the Design, Construction, Calibration, and Testing of a Custom Langmuir Probe for Use in an RF Plasma Chamber
Date
2019-12
Authors
De La Garza, Andres Edelmiro
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Abstract
<p>A particular interest of the principal investigator regarding a rare atmospheric
phenomenon called ball lightning influenced the design and construction of a custom RF
plasma chamber. However, the primary focus of this experiment is not on the ball
lightning but instead on the interesting phenomenon that occurs when RF plasma is near
its plasma frequency. At its plasma frequency, it behaves as a metamaterial which are
said to exhibit interesting microwave properties. A Langmuir probe was needed to be
built to collect data on the plasma density and find relationships between plasma density
and how well it acts as a waveguide.</p>
<p>A custom plasma chamber was then designed and built for the purpose of testing
the microwave attenuation/dispersion characteristics (S-parameters) of a cylindrically
symmetric RF plasma (13.56 MHz). The principal investigator was interested in studying
how plasma electron density affects waveguide dispersion characteristics.</p>
<p>Since commercially available Langmuir probes were beyond the project budget a
Langmuir probe as well as the associated sensing circuitry was designed, built, tested and
calibrated in-house. The necessary theoretical background needed to understand the
probe and sensing circuitry is presented as well as construction of the probe and sense
circuitry.</p>
Description
Keywords
Langmuir probe, RF compensation, Plasma
Citation
De La Garza, A. E. (2019). <i>On the design, construction, calibration, and testing of a custom Langmuir probe for use in an RF Plasma</i> (Unpublished thesis). Texas State University, San Marcos, Texas.