Journal ArticleDOI
Automatic display of electron density in a plasma column
Th G van de Roer,J.J.M. Kwaspen +1 more
TLDR
In this article, a method to obtain a voltage proportional to the average electron density in a gas discharge tube of small diameter is described, which is based on the well known cavity method, and the voltage which controls the oscillator frequency is made to vary linearly with the frequency and hence with the electron density.Abstract:
A method is described to obtain a voltage proportional to the average electron density in a gas discharge tube of small diameter. The method is based on the well known cavity method. The cavity in which the plasma column is placed is inserted in a feedback circuit known as the Pound stabilization circuit, which was originally devised as a means to stabilize the output frequency of a microwave oscillator on the resonant frequency of a cavity. In the method described here, the oscillator frequency is made to follow the cavity resonant frequency. The voltage which controls the oscillator frequency is made to vary linearly with the frequency and hence with the electron density.read more
Citations
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Patent
Stabilized oscillator circuit for plasma density measurement
TL;DR: In this paper, a method and system for controlling electron densities in a plasma processing system was proposed, by applying a dither voltage and a correction voltage to a voltage-controlled oscillator.
Patent
Electron density measurement and plasma process control system using a microwave oscillator locked to an open resonator containing the plasma
TL;DR: In this article, a system for measuring plasma electron densities (e.g., in the range of 10?10 to 1012 cm-3?) and for controlling a plasma generator (240) is presented.
Patent
Electron density measurement and plasma process control system using changes in the resonant frequency of an open resonator containing the plasma
TL;DR: In this article, a programmable frequency source (201) sequentially excites a number of the resonant modes of an open resonator placed within the plasma processing apparatus, depending on the plasma electron density in the space between the reflectors.
References
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Journal ArticleDOI
Resonances of a Microwave Cavity Partially Filled with a Plasma
B. Agdur,B. Enander +1 more
TL;DR: In this article, the resonant behavior of a cylindrical microwave cavity partially filled with a cold plasma of arbitrarily large density is studied theoretically and experimentally, and curves showing the resonance frequencies as functions of the plasma density are given for the lower order modes.
Journal ArticleDOI
Microwave Plasma Density Measurements
TL;DR: In this article, an analysis was made for the TM010 mode to determine the effects of nonuniformity (a parabolic density) and of the holes in the cavity where the plasma column is admitted.
Journal ArticleDOI
The application of phase-lock microwave frequency stabilizers to electron paramagnetic resonance spectrometers
H A Buckmaster,J C Dering +1 more
TL;DR: In this article, the frequency of the microwave power source is phase-locked to a high stability (MHz) crystal oscillator, while retaining the spectral purity obtained by phase-locking the power source to an electron paramagnetic resonance spectrometer.
Journal ArticleDOI
A simple sensitive X-band superheterodyne spectrometer for electron spin resonance measurements
C M G Zwarts,D van Ormondt +1 more
TL;DR: In this paper, a single klystron superheterodyne X-band electron spin resonance spectrometer was constructed for sensitive measurements in a wide power region, 0.4 μw-4 mw.