Measurement of secondary ionization coefficient of CaO film electrode

An experimental investigation of Townsend's secondary ionization coefficient γ is carried out for MgO, SrO and CaO film electrodes. These oxides are utilized, or are to be utilized, in next-generation plasma display panels. All of the experiments are performed in argon. In particular, in the case of CaO film, our attention is attracted to the effect of charge accumulated on CaO film. For this purpose, the breakdown voltage V s is observed from waveforms of the gap voltage and charge accumulated on the dielectric film electrodes with the repeated breakdown. Townsend's criterion is utilized to estimate γ from the breakdown voltage. In the case of the CaO film, γ increases gradually with repeated breakdowns and reaches a stationary value. The increase of γ is considered to be due to the charge that accumulates on the dielectric electrode triggering the next breakdown. Therefore, it is concluded that the increased γ is sustained by a combined process consisting of restarted electrons that have accumulated on the CaO film and the original γ action, as observed in metallic electrodes in a low-pressure gas discharge.

Section: Mechanism Underlying the Variation Of γmentioning

confidence: 87%

“…The experimental apparatus and procedure are briefly described here because they have already been reported [10,13]. An enlarged picture of the electrode system is shown in figure 1.…”

Section: Experimental Apparatus and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Secondary ionization coefficientγof MgO, SrO and CaO and the correlation betweenγand charge accumulated on CaO in argon

Suzuki¹

2014

“…We previously reported the secondary ionization coefficients for MgO, SrO and CaO film electrodes and the charge accumulated on them [9,23,24]. The results of the experiments suggested a positive correlation between the secondary ionization coefficient and the charge accumulated on a CaO film.…”

Section: Introductionmentioning

confidence: 95%

Gradual increase in secondary ionization coefficientγand charge accumulation on a dielectric electrode during DBD with repeated breakdown

Suzuki

2015

We have investigated the effect of the surface roughness of a dielectric electrode for dielectric barrier discharge (DBD). We prepared three alumina plates made from the same material with different surface roughnesses for use as electrodes. During the repeated breakdown from the first breakdown to the stationary state, we observed gradual increases in the secondary ionization coefficient and the charge accumulated on the alumina electrodes under the application of a sinusoidal voltage in argon up to a pressure of 105 Torr. A strong correlation was also observed between them, similarly to in a previous paper on CaO film electrodes. The results suggest that increasing the surface roughness of an alumina electrode results in a larger secondary ionization coefficient and greater charge accumulation on the electrode. Moreover, it is concluded that the charges that accumulate on the alumina can be liberated from the surface as initial electrons when it acts as a cathode, depending on the polarity of the alternating gap voltage. These electrons induce the formation of an atmospheric-pressure Townsend discharge. Finally, we discuss the effect of the secondary ionization coefficient in DBD.

“…[40]. We are also investigating phenomena related to the accumulation of electrons on a dielectric electrode [41][42][43].…”

Section: Formation Of Hexagonal Arrayed Patternmentioning

confidence: 99%

Hexagonal arrayed patterns with bright and dark spots observed in a compact plasma reactor based on a piezoelectric transformer

Suzuki

2014

In this paper, we describe the formation of hexagonal arrayed patterns in a compact plasma reactor that consists of a piezoelectric transformer (PT) and a dielectric electrode. A high voltage induced on the PT surface by the piezoelectric effect generated diffuse glow-like and patterned dielectric barrier discharges (DBDs) in a gap. Vacuum ultraviolet (VUV) spectroscopy was applied to observe light emitted from Xe * 2 and Ar * 2 excimers, which were formed in a He-Xe mixture and pure Ar, respectively. Peaks at 172 and 126 nm were observed in the emission spectra. Hexagonal arrayed patterns were observed in both He and Ar by adding a small amount of air. Then, static and time-resolved images of the hexagonal arrayed patterns were captured using a single-lens reflex camera and an intensified charge-coupled device camera, respectively. The hexagonal arrayed patterns alternately exhibited bright and dark spots in weak uniform emission on the PT surface depending on the applied sinusoidal voltage. Both patterns were similar in the observed time-resolved images. Thus, it was confirmed that the observed dark spots were the traces of accumulated charges on the PT. Here, we discuss the necessary conditions for the generation of such patterns in terms of the charges accumulated on the PT and compare our results with those reported elsewhere.