• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.383-387
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• 2007

In this paper the design of the discharge cleaning system for KSTAR vacuum vessel is described. We first discuss about the parameters which are related the efficiency of discharge cleaning. The RG(RF-assisted Glow) discharge which has the ignition and sustain pressure lower than those in the case of DC discharge, thus has the higher efficiency of discharge cleaning. So we adopt the RG discharge, in practical design, for KSTAR discharge cleaning system. For uniformity of the cleaning effect, we plan to install two discharge cleaning systems in A- and I-port of the KSTAR vacuum vessel. The designed system will be adapted for the study of the fuel recycling and of the boronization as well as the discharge cleaning of the KSTAR vacuum vessel.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1382-1384
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• 1995

In order to study the structure of RF glow discharge driven at 13.56MHz in argon, the discharge voltage, current and phase shift between them will be measured over a wide range of discharge parameters(gas pressure between 1mTorr and 50mTorr with discharge power between 20mW and 200W). In this paper, the dc glow discharge characteristics and plasma parameters of both FTS and CPMS systems are studied experimentally. It is found that for CPMS system discharge is stablized under wider ranges of magnetic field and pressure than for FTS system. The plasma density and electron temperature of the plasma for these two systems are in the range of $10^{10}{\sim}7{\times}10^{11}[cm^{-3}]$ and $3.5{\sim}6.5$[eV], respectively.

• Analytical Science and Technology
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• v.7 no.2
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• pp.155-164
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• 1994

A conventional Grimm-type glow discharge source was constructed and applied to radio-frequency(13.56MHz) discharge for metal and ceramic analysis. We investigated the emission spectrum for aluminium and aluminium oxide and the influence of discharge operating paramaters including argon pressure, rf-power and DC-bias voltages at the sample-side electrode. Scanning Electron Microscope(SEM) also was used to investigate the effect of rf-sputtering on the microstructure formation of the aluminium oxide. Linear analytical calibration curves were constructed for Manganese and zinc element in samples of low alloy steel(BAS 401-405) and brass(NIST 1108-1117).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.8
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• pp.622-628
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• 2001

We developed 1- and 2-dimensional fluid model for the analysis of a capacitively coupled Ar RF(Radio Frequency) glow discharge. This discharge is in pure Ar gas at the pressure 100[mTorr], frequency 13.56[MHz] and voltage amplitude 120[V}. This model is based on the equations of continuity and electron energy conservation coupled with Poison equation. 2-dimensional model is simulated on the condition of GEC(Gaseous Electronic Conference cell). The geometry of the discharge chamber and the electrodes used in the model is cylindrically simmetric; tow cylinders for the electrodes are surrounded by the grounded chamber. It is shown that 1-dimensional model is very useful on the understanding of RF glow discharge property and of the movement of charged particles. 2-dimensional model predicts off-axis maximum structure as in the experiments and has the results in qualitatively and quantitatively good agreement with the experiments. Effects of dc self-bias voltage, guard ring and reactor geometry is discussed.

• Analytical Science and Technology
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• v.8 no.1
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• pp.69-77
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• 1995

The instrumentation and operating characteristics of a gas-jet assisted radio frequency glow discharge atomic absorption spectrometry(RF-GDAAS) are studied. The roles of discharge power, pressure as well as gas flow rate on the sample loss rate and absorbance are described in this paper. Results show that the optimum discharge conditions depend on pressure and discharge power as well as on the gas flow rate. The gas flow rate plays as an important parameter in RF-GDAAS. Absorbance increases as the gas flow rate increase up to 600ml/min., and the optimum absorbance is obtained at the pressure of 3 mbar. The absorbance increases when the discharge power increases as expected, however, the instability of the system due to the heat might be the trade off factor. The linear calibration curves of Ni and Cr in stainless steel(BAS 461-468) and brass (KSS 1121-1126) are obtained with RF-GDAAS.

• Journal of the Korean Vacuum Society
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• v.10 no.3
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• pp.298-302
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• 2001

Cleaning effect of RF/DC discharge to clean the surface of vacuum chamber was studied for various discharge conditions. Glow discharge cleaning without baking reduced the outgassing rate to 1/2, which was similar to that after the only baking treatment alone. Glow discharge cleaning treatment with baking improved the cleaning efficiency and then the outgassing rate was remarkably reduced to 1/20. It was found that the ion energy and the ion density were important factors in cleaning the surface. RF discharge cleaning was more effective than BC discharge cleaning.

• Proceedings of the KIEE Conference
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• 1985.07a
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• pp.224-227
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• 1985

During operation of an RF glow discharge system, it can be observed that the reflected power tends to increase in small value, due to changes in the impedance of the system. This problem can be relieved by adding an automatic impedance matching circuit to the system. This paper presents a detailed method of automatically matching the input impedance of a 50 ohm transmission line to an RF glow discharge system at 13.56 MHZ.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1838-1840
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• 1996

In order to study the relationship between the physical properties of glow discharge plasma and the physical behavior of TiN thin film, electrical characteristics of RF discharge plasma driven at 13.56MHz in a parallel-plate electrode system were measured. Plasma parameters, such as electron density and temperature, are also studied since they may be considered as one of the very important factors deciding the physical properties of TiN thin film under given conditions of applied biasd voltage and pressure. The TiN thin film were fabricated over a wide range of discharge conditions, and some of the general relationships between the measured plasma parameters and the properties of TiN thin film were discussed.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.73-78
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• 2004

A highly sensitive detecting method has been developed for determining part per billion of sulfur in $H_2S$/Ar plasma. The method is based on the excitation of Ar/$H_2S\;or\;Ar/H_2S/O_2$ mixture in hollow cathode glow discharge sustained by radiofrequency (RF) or 60 Hz AC power and the spectroscopic measurement of the intensity of emission lines from electronically excited $S_2^*\;or\;SO_2^*$ species, respectively. The RF or AC power needed for the excitation did not exceed 30 W at a gas pressure maintained at several mbar. The emission intensity from the $SO_2^*$ species showed excellent linear response to the sulfur concentration ranging from 5 ppbv, which correspond to S/N = 5, to 500 ppbv. But the intensity from the $S_2^*$ species showed a linear response to the $H_2S$ only at low flow rate under 20 sccm (mL/min) of the sample gas. Separate experiments using $SO_2$ gas as the source of sulfur demonstrated that the presence of $O_2$ in the argon plasma is essential for obtaining prominent $SO_2^*$ emission lines.

• Analytical Science and Technology
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• v.15 no.3
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• pp.236-242
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• 2002

A method was investigated to determine the thickness of coating on steel sheet using rf glow discharge atomic emission spectrometer. The RF gas-jet boosted glow discharge has such salient feature as good pleasure stability and high sputtering efficiency that it was possible to determine the thickness of silicon resin film on zinc electroplated steel. The erosion speed variation is dependent on discharge power, gas flow rate and discharge pressure. therefore determine discharge condition to measure the thickness of coating on steels. The fundamental studies have been carried out to investigate an optimum condition for in-depth analysis and composition of zinc coating on steel. In this study, the calibration curve for thickness determination of silicon resin film was found to be linear in the range of $1000{\sim}3500mg/m^2$ film thickness. The developed rf gas-jet boosted glow discharge was applied to the analysis of zinc coating and silicon resin film on steel made by RIST.