An RF microplasma facility development for medical applications

Pérez-Martínez, J.A.; Peña‐Eguiluz, R.; López-Callejas, Régulo; Mercado-Cabrera, A.; Valencia, R.; Barocio, S. R.; Benítez-Read, Jorge Samuel; Pacheco-Sotelo, J.O.

doi:10.1016/j.surfcoat.2006.07.056

Cited by 19 publications

(9 citation statements)

References 3 publications

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“…Discharges between a cathode which contains a hollow structure and an arbitrarily shaped anode are generally called hollow cathode discharges, which have many applications in various fields, such as light sources, [1][2][3] gas lasers, [4][5][6] surface treatment, 7,8 sterilization, 9,10 and electric propulsion. [11][12][13] The typical low-pressure discharge with a hollow cathode effect usually has advantages of higher concentrations of electrons and ions and lower breakdown and operating voltages compared with traditional normal glow discharges.…”

Section: Introductionmentioning

confidence: 99%

Transition characteristics of low-pressure discharges in a hollow cathode

Verboncoeur

Christlieb

et al. 2017

Physics of Plasmas

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Based on a two-dimensional (2-D) fluid model, the transition processes of discharges in a hollow cathode at low pressure are observed by changing three parameters, i.e., applied voltage U 0 , gas pressure p, and external circuit ballast resistance R b. The voltage-current characteristic curves, electron density distributions, and electric potential distributions of different discharge operating points in a hollow cathode are obtained. The transition processes are characterized by the voltage-current characteristic curves, the electron density distributions, and the electrical potential distributions. The transition modes observed from the voltage-current characteristics include the low-current abnormal mode, normal mode, and high-current abnormal mode. Increasing the applied voltage U 0 can have a similar effect on the discharge transition processes to decreasing the ballast resistance. By increasing U 0 from 200 V to 500 V and decreasing R b from 5000 kX to 100 kX independently, it is observed that the discharge transfers from the outside to the inside of the hollow cavity, thus forming the virtual anode potential. By increasing the gas pressure p from 50 Pa to 5 kPa, the discharge also moves into the hollow cavity from the outside; however, a further increase in the gas pressure leads to the discharge escaping from the hollow cavity. Simulation results and characterizations for different parameters are presented for the transition properties of low-pressure discharges in a hollow cathode. It is verified that the hollow cathode discharge only exists under certain ranges of the above parameters. Published by AIP Publishing.

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Section: Introductionmentioning

confidence: 99%

Transition characteristics of low-pressure discharges in a hollow cathode

Verboncoeur

Christlieb

et al. 2017

Physics of Plasmas

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“…Microplasmas have attracted growing attention in recent years because of possible applications in various fields such as surface treatment, 1,2 sterilization, 3,4 light sources, [5][6][7] or micropropulsion. 8,9 One of the interest of microplasmas lies in the fact that they can be generated at atmospheric pressure with a very low injected power compared to other nonthermal plasmas.…”

Section: Introductionmentioning

confidence: 99%

A global model of the self-pulsing regime of micro-hollow cathode discharges

Lazzaroni

Chabert

2012

Journal of Applied Physics

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International audienceA global (volume-averaged) model of the self-pulsing regime of micro-hollow cathode discharges working in argon gas is proposed. The power balance is done using an equivalent circuit model of the discharge that allows the current and voltage dynamics to be calculated. The fraction of the total power dissipated in the discharge that contributes to electron heating is deduced from a sheath model previously described. The particle balance is first done in a very simplified reaction scheme involving only electrons, argon atomic ions, and argon molecular ions. In a second step, the excited states (the metastable state Ar*(3P2) and the resonant state Ar*(3P1)) are included in the particle balance equations. The models are compared to experiments and several conclusions are drawn. The model without excited states underestimates the electron density and does not capture well the trends in pressure. The model with the excited states is in better agreement which shows that multi-step ionization plays a significant role. The time-evolution of the electron density follows closely that of the discharge current but the excited states density presents two peaks: (i) the first at the early stage of the current peak due to direct excitation with high electron temperature, (ii) the second at the end of the current (and electron density) peak due to large production of excited states by electron-ion recombination at very low electron temperature

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“…Field gas ionization system is capable of ionizing the gas molecules by loading a low voltage on the electrodes and is favorable for many potential applications, for example, sensors, , environmental remediation, spectrometry, − and biomedicine . Among them, ionization gas sensors have attracted extensive interest for their advantages like high selectivity and fast response/recovery. , Ionization gas sensing is substantially based on the separation of the positive and negative charges of a gas molecule. , By ionizing the target gas, a specific current–voltage characteristic can be generated as the “fingerprint” of the gas component. , The main disadvantages of traditional bulky ionization gas sensors, for example, high power consumption and risky high operation voltage, hinder their practical application. − Therefore, one-dimensional nanomaterials with ultrasharp tips, for example, carbon nanotubes, as well as ZnO, Si, or CuO nanowires (NWs), − are equipped onto the traditional macroscopic electrodes in order to lower both the operation voltage and the current.…”

Section: Introductionmentioning

confidence: 99%

Crystalline-to-Amorphous Phase Transformation in CuO Nanowires for Gaseous Ionization and Sensing Application

et al. 2021

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We report a dramatic reduction of operation voltage of a CuO nanowire-based ionization gas sensor due to the crystalline-to-amorphous phase transformation. The structural change is attributed to the ion bombardment and heating effect during the initial discharge, which brings about the formation of abundant nanocrystallites and surface states favoring gaseous ionization. The gas-sensing properties of the CuO nanowire sensor are confirmed by differentiating various types or concentrations of volatile organic compounds diluted in nitrogen, with a low detection limit at the ppm level. Moreover, a sensing mechanism is proposed on the basis of charge redistribution by electron-gas collision related to the specific ionization energy. The insightful study of the electrode microstructure delivers an exploratory investigation to the effect of gas ionization toward the discharge system, which provides new approaches to develop advanced ionization gas sensors.

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An RF microplasma facility development for medical applications

Cited by 19 publications

References 3 publications

Transition characteristics of low-pressure discharges in a hollow cathode

Transition characteristics of low-pressure discharges in a hollow cathode

A global model of the self-pulsing regime of micro-hollow cathode discharges

Crystalline-to-Amorphous Phase Transformation in CuO Nanowires for Gaseous Ionization and Sensing Application

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