Temperature and electron density measurements in a helium/hydrogen capacitively coupled microwave plasma

Masamba, W.R.L.; Ali, Aleem Azal; Winefordner, J. D.

doi:10.1016/0584-8547(92)80041-e

Cited by 29 publications

(4 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many observations made in the present study fit the recently developed understandings of the structure of plasma torch afterglows. Indeed, it is shown here, as it has been elsewhere [23,[47][48][49][50], that the local thermodynamic equilibrium model does not apply, as electrons are far hotter than all other species, and even rotational temperature and excitation temperature are clearly not in equilibrium. Also, the measured rotational temperatures and electron densities are very close to those measured by others [6,23,51,52].…”

Section: Discussionmentioning

confidence: 70%

Impact of aerosol particles on the structure of an atmospheric pressure microwave plasma afterglow

Chen

Phillips

2002

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Several novel ceramic processing technologies (e.g. oxide ceramic melting and spheroidization) using an atmospheric pressure microwave plasma torch were recently developed in our lab. Understanding the processes and optimization requires complete characterization of the plasma as a function of operating condition. As a first step, a non-intrusive spectroscopic method was employed to map rotational (gas), electron and excitation temperatures and electron densities of the afterglow region of microwave generated atmospheric plasmas with and without alumina particle aerosol. Two-dimensional spatially resolved mapping of rotational (gas), excitation and electron temperatures and electron densities as a function of operating conditions during material processing were developed. It was shown that the passage of an aerosol dramatically changes the structure of the afterglow. Also the non-equilibrium nature of microwave generated atmospheric argon plasma was confirmed, suggesting that only multi-temperature models are capable of modelling this region of the plasma.

show abstract

Section: Discussionmentioning

confidence: 70%

Impact of aerosol particles on the structure of an atmospheric pressure microwave plasma afterglow

Chen

Phillips

2002

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…The rotational temperatures determined from the OH spectra are in good agreement with temperatures obtained for other plasma spectral sources. They are similar, in their dependence on operating conditions and observation modes, to the rotational temperatures determined in a CMP 27 or in a FAPES source. 28 The rotational temperature values (2150-2760 W) are similar to those measured in a He CMP (1800-3000 K) but higher than those from He FAPES (580-1400 K).…”

Section: Rotational Temperaturesmentioning

confidence: 59%

Characterization of a very low power argon CCP

Anghel

Simon

Frențiu

2005

J. Anal. At. Spectrom.

View full text Add to dashboard Cite

“…Most work involving the addition of hydrogen has focused on its effect in the ICP. It was recently shown 27,28 that the high thermal conductivity of hydrogen can raise gas-kinetic temperatures in the center of the ICP and can offer a more stable environm ent for viewing analyte emission. An argon/oxygen mixed gas m icrowave plasma was investigated by Kollotzek et al 29 The added oxygen allowed high percentages of methanol to be introduced into the MIP, which made it a suitable detector for high-performance liquid chromatography.…”

Section: Resultsmentioning

confidence: 99%

Inductively Coupled Plasma/Microwave-Induced Plasma Tandem Source for Atomic Emission Spectroscopy

Pack

Hieftje

2000

Appl Spectrosc

View full text Add to dashboard Cite

A microwave-induced plasma (MIP)/inductively coupled plasma (ICP) combination has been evaluated as an “atomization-excitation” tandem source (TS). The results indicate that some of the problems reported for similar sources in the past can be effectively reduced or eliminated. Desolvation of the analyte aerosol before its introduction into the tandem source improved detection limits only slightly. However, power modulation of the microwave plasma served to improve tandem-source performance in two ways. First, noise contributed by the ICP and the MIP was isolated one from the other. Since the modulation frequency was chosen to be far removed from the major noise frequencies observed from either of the two sources, more stable background signals were realized. Second, the intense background signal from the ICP could be discriminated against through use of a lock-in-amplifier tuned to the modulated MIP signal. Relative standard deviations of both the signal and the background were usually below 1% when the MIP power was modulated. Detection limits ranged from 0.53 ppb to 40 ppb for the elements examined, which represents an improvement of 5-to 40-fold over previously reported data for a similar tandem-source configuration. Disappointingly, these improved detection limits were still much worse than detection limits obtained by other investigators utilizing the ICP alone. Addition of a mixed gas did little to improve the performance of the tandem source; for barium and calcium ion lines, an increase of approximately three in signal-to-background ratios was observed upon the addition of hydrogen or helium.

show abstract

Temperature and electron density measurements in a helium/hydrogen capacitively coupled microwave plasma

Cited by 29 publications

References 29 publications

Impact of aerosol particles on the structure of an atmospheric pressure microwave plasma afterglow

Impact of aerosol particles on the structure of an atmospheric pressure microwave plasma afterglow

Characterization of a very low power argon CCP

Inductively Coupled Plasma/Microwave-Induced Plasma Tandem Source for Atomic Emission Spectroscopy

Contact Info

Product

Resources

About