Corinne Foissac

• University of Lille

The Vibrational Distribution Function of the N2(C, v’=0-4) state is analyzed by using optical emission spectroscopy in N2-Ar (0-95% Ar) discharge induced by a helical cavity excited at 27 MHz and 200 Pa. The state-to-state modelling shows that the kinetics involving N2(A) metastable specie becomes dominant with increasing the Ar amount in the gas...

We are presenting an experimental study of an Ar-H2O radiofrequency (RF) discharge at 67 and266 Pa, excited by an original helical plasma source at 27 MHz and power of 30 W. The argon percentagein the mixture was changed from 0 to 95 %. Oxygen and hydrogen atomic lines together with molecularemissions originated from the OH(A2S+) and N2(C3Pu) state...

This paper presents results from both experimental and modelling studies of a flowing afterglow in N2–O2 mixtures observed in a plasma-chemical reactor. The plasma is generated at a pressure of 440 Pa by a microwave cavity working at the excitation frequency of 433 MHz. The main nitrogen and nitrogen oxide species are experimentally studied, mainly...

An Ar-H2O discharge with Ar content from 0 to 95 % at 67 and 266 Pa have been studied by optical emission spectroscopy. The plasma was excited at 27 MHz by a helical cavity with a power set at 30 W. The rotational temperatures of N2(C3Πu) and OH(A2 Σ + ) emitters were determined through spectral simulations. For added Ar percentages smaller than 95...

The Vibrational Distribution Function of the N2(C, v’=0-4) state is analyzed by using optical emission spectroscopy in N2-Ar (0-95% Ar) discharge induced by a helical cavity excited at 27 MHz and 200 Pa. The state-to-state modelling shows that the kinetics involving N2(A) metastable specie becomes dominant with increasing the Ar amount in the gas m...

Optical emission spectroscopy, ranging from visible to near infrared, is used to determine densities and rotational temperatures of N2(B 3Πg) and N2(C 3Πu) states in a nitrogen–argon (0–95% Ar) discharge, under moderate pressures (200–400 Pa). The plasma is sustained by a helical cavity with an excitation frequency of 27 MHz and power fixed to 28 W...

The vibrational distribution function (VDF) of the N2(C 3Πu, v' = 0–4) state is analysed using optical emission spectroscopy in a nitrogen–argon (0–95% Ar) plasma sustained at a pressure of 400 Pa. A helical cavity is used as the plasma source with an excitation frequency of 27 MHz and power of 28 W. In the case of a pure nitrogen discharge, the N2...

A kinetic model is discussed for the two main emitting species (N2(B), N2(C)) of a N2-Ar plasma excited at 27 MHz by a helical cavity with operating pressure of 200 Pa. The present paper consistently illustrates, for miscellaneous Ar fractions and different positions, the great influence of the processes involving the metastable species (N2(A),...

This paper deals with a spectroscopic characterization of an N 2-Ar discharge at 400 Pa excited at 27 MHz with a power of 28 W. The main parameters for industry applications, as gas temperature and plasma kinetics are briefly discussed as also the crucial effect of Ar addition on the reaction scheme.

This paper deals with a spectroscopic characterization of an Ar-H2O discharge excited by a helical cavity at 27 MHz. The power and the pressure are fixed to 30 W and 266 Pa, respectively. Emissions from Ar, H, O atoms and the OH(A2Σ+→X2Π) molecular spectral system are studied spatially along the discharge as a function of gas composition. Besides,...

Optical emission spectroscopy was applied to study vibrational and rotational temperatures of N2 molecule in nitrogen-argon (0–95% Ar) plasma sustained at a pressure of 400 Pa by a helical cavity supplied with a power of 28 W. The emissions were observed from the first (1 +) and second (2 +) positive systems of N 2 along cavity axis in visible rang...

This work presents the spatial profile of gas temperature (T g) of Ar-N 2 plasma induced by a helical cavity excited at 13.56 MHz. T g is examined through rotational temperatures of first positive (1 +) and second positive (2 +) emission systems. Rotational temperatures are deduced by comparison of simulated spectra with measured spectra. Investiga...

Optical emission spectroscopy in Vacuum Ultra-Violet spectral range is applied to study densities, vibrational and rotational temperatures of N2(a1Πg) specie in a N2-Ar (0-95% Ar) plasma induced by a helical cavity excited at 27MHz and 400Pa. The N(2P) atoms are also analyzed versus the Ar percentage. The strong dependence of the temperatures and...

Optical emission spectroscopy in vacuum ultraviolet and UV spectral ranges is applied to study densities, and vibrational and rotational temperatures of the N2 molecule in a nitrogen–argon (0–95% Ar) plasma sustained at a pressure of 400 Pa by a helical cavity supplied with a power of 28 W and an excitation frequency of 27 MHz. The spatial investig...

This paper presents the spatial characterization of Ar plasma induced by a broad-band helical coupling device at low pressure (15 Pa). The electric field analysis outside the helix but within the coupling device is carried out by electrostatic probe for several excitation frequencies ranging from 13.56 to 433 MHz. The results prove that this helica...

The densities of most emitting species and gas temperature (Tg) are investigated in a nitrogen DC pulsed discharge. The discharge current and gas pressure are varied from 70 to 150 mA and 133 to 470 Pa, respectively. Tg is determined through rotational temperatures of first positive (1+) and second positive (2+) emission systems. These temperatures...

This paper presents the spatial characterization of Ar-N2 plasma induced by a helical cavity excited at 27 MHz and moderated pressure (400 Pa). The axial profiles of densities and gas temperature are determined through the emissions of the first positive (1+) and second positive (2+) systems of N2. Additionally, in case of pure argon plasma, the OH...

The BH A 1Π → X 1Σ+ (0–0) transition was studied, in the emission mode, for gas temperature determination. Two typical conditions were used: doped diamond deposition conditions (H2/CH4/B2H6 99%:1%:0–100 ppm, from 2500 to 7550 Pa) and the vessel cleaning condition (H2, 85 Pa). Among the P, Q and R branches of the A 1Π → X 1Σ+ (0–0) transition, only...

To gain an understanding of the processes responsible for the formation of the well-known short-lived afterglow (SLA) or pink afterglow of nitrogen, different diagnostic techniques are implemented in the afterglow of a 440 Pa microwave nitrogen discharge in a 3.8 cm diameter flow tube. Using the intracavity laser absorption spectroscopy technique,...

Both the axial density and temperature profiles of ground-state nitrogen atoms have been measured in a microwave discharge and its afterglow in the presence of the so-called short-lived afterglow by means of two-photon absorption laser-induced fluorescence (TALIF). The temperature is obtained from the Doppler broadening of the spectral profile, aft...

To gain an understanding of the processes responsible for the formation of the well-known short-lived afterglow (SLA) or pink afterglow of nitrogen, different diagnostic techniques are implemented in the afterglow of a 440 Pa microwave nitrogen discharge in a 3.8 cm diameter flow tube. Using the intracavity laser absorption spectroscopy technique,...

The first absolute density measurement of N2(A 3Σ+u;v = 0) metastable molecules in the short-lived nitrogen afterglow of a 440 Pa microwave discharge is achieved by using a intracavity laser absorption spectroscopy technique. The results obtained show that this technique is very well suited for the diagnostics of N2(A 3Σ+u) in the nitrogen afterglo...

The temperature time evolution of a Pyrex plate is determined by measurements of its reflectance when placed in the early afterglow of a microwave discharge in flowing nitrogen. For comparison, simultaneous monitoring by optical emission spectroscopy is performed both in the discharge and the so-called short-lived afterglow. After t2 min, the spect...

Properties both of the discharge and of the post-discharge region are studied through the so-called short-lived afterglow generated at 340 Pa by two similar coaxial cavities resonating at 433 and 2450 MHz. Simultaneous Raman Stokes scattering and optical emission spectroscopies are performed. The gas temperature profiles of the various regions are...

An original technique, using microwave plasmas in pure nitrogen and mixed with hydrogen, is implemented in the aim of surface nitridation of a sodium metaphosphate glass. The microwave discharges, ignited at pressures in the range of hundred Pa, are characterised by high concentrations of excited and ionised species. In the case of nitrogen plasmas...

A quantitative study of spectra obtained by Raman-Stokes scattering enables the determination of the kinetic temperature of the N2(X1 Σg+) molecule in the short lived afterglow appearing downstream from a microwave discharge in flowing pure nitrogen. The obtained value agrees with the rotational temperature deduced from the emission spectra of the...

The densities of most emitting species and gas temperature (Tg) are investigated in a nitrogen DC pulsed discharge. The discharge current and gas pressure are varied from 70 to 150 mA and 133 to 470 Pa, respectively. Tg is determined through rotational temperatures of first positive (1+) and second positive (2+) emission systems. These temperatures...

This paper presents the spatial characterization of Ar-N2 plasma induced by a helical cavity excited at 27 MHz and moderated pressure (400 Pa). The axial profiles of densities and gas temperature are determined through the emissions of the first positive (1+) and second positive (2+) systems of N2. Additionally, in case of pure argon plasma, the OH...