Thomson scattering experiments on a 100 MHz inductively coupled plasma calibrated by Raman scattering

Regt, de Jm Hans; Engeln, Rah Richard; Groote, de Fpj Frank; Mullen, van der Jjam Joost; Schram, DC Daan

doi:10.1063/1.1146444

Cited by 57 publications

(40 citation statements)

References 9 publications

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“…For the measurements of the radial gradient length, the same set-up is used as for the previously reported global Thomson scattering measurements [9,23]. The main difference is that now the laser beam is focused at the position of the plasma, in order to obtain a good spatial resolution.…”

Section: Experimental Determination Of the Gradient Lengthmentioning

confidence: 99%

“…The main difference is that now the laser beam is focused at the position of the plasma, in order to obtain a good spatial resolution. In the past [23] the focus of the laser beam was situated behind the plasma to avoid the possibility that stray light from the ablation of dust particles is detected during the calibration procedure. To avoid interference with this signal a dust free chamber is constructed surrounding the plasma, for the measurements presented now.…”

Section: Experimental Determination Of the Gradient Lengthmentioning

confidence: 99%

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Steep plasma gradients studied with spatially resolved Thomson scattering measurements

Jonkers

Selen

Mullen

et al. 1997

Plasma Sources Sci. Technol.

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Abstract. Plasmas created by the microwave torch Torcheà Injection Axiale (TIA), which are around 2 mm in diameter and 15 mm long, are investigated. In these plasmas large gradients are present so that the edge is supposed to play an important role. Using global Thomson scattering measurements, in which global refers to the fact that the size of the laser beam is approximately equal to the diameter of the plasma, the electron densities and temperatures were determined. However, these results lead to discrepancies in the particle balance: the production of free electrons is much larger than the classical losses due to recombination, convection and diffusion. Radially resolved Thomson scattering measurements show the plasma has a hollow structure. Although this enhances the losses due to diffusion, still a large discrepancy remains between production and destruction of free electrons in the argon plasmas. Probably some molecular processes are significant as well. A good candidate is the charge transfer between argon ions and nitrogen molecules, since mixing with the surrounding air has a large impact on the plasma.

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Section: Experimental Determination Of the Gradient Lengthmentioning

confidence: 99%

Section: Experimental Determination Of the Gradient Lengthmentioning

confidence: 99%

Steep plasma gradients studied with spatially resolved Thomson scattering measurements

Jonkers

Selen

Mullen

et al. 1997

Plasma Sources Sci. Technol.

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“…However, it gives valuable information on the 4s density [8]. ¹homson scattering is the scattering of electromagnetic (EM) radiation by free (or loosely bound) electrons [9,10]. It can be seen as a combination of two processes: the forced vibration of electrons absorbing the radiation and emission by these oscillating charges.…”

Section: Passive Spectroscopymentioning

confidence: 99%

An active spectroscopical study on the plasma parameters of an ICP

Mullen

Regt

1996

Fresenius J Anal Chem

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Various techniques to measure the electron density and temperature of a 100 MHz inductively coupled plasma (ICP) are compared with each other. Apart from passive spectroscopy of measuring the shape of (e.g. H(beta)) and the area under emission lines we explored the field of active spectroscopy. Non-intrusive and specific are the methods of diode laser absorption (DLA) of an argon 4s-4p transition and Thomson scattering (TS). Intrusive and global is the power interruption (PI) technique: the response of line (argon and analytes) and continuum emission is followed during PI. Finally, a combination of two active techniques, namely TS during PI, is studied. By using the different techniques on the same plasma condition (frequency, power and flows) this intercomparison will reveal the validity region of the various techniques. In this way a strong basis will be created for understanding plasma phenomena.

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“…Raman scattering offers the advantage that the scattered signal is at different wavelengths with respect to stray light and Rayleigh scattering. Raman calibration has been used by De Regt et al [20] and van Gessel et al [21]; hence it represents an alternative method for the absolute calibration.…”

Section: Measuring Procedures and Data Analysismentioning

confidence: 99%

“…The Raman calibration method is similar to the one used by de Regt et al [20] and van de Sande et al [22]. The scattered Raman power, P RM , was obtained from the fitting of the characteristic nitrogen Raman spectrum at a controlled pressure and temperature [26] and thus for a known gas density n g .…”

Section: A Calibrationmentioning

confidence: 99%

Electron density and temperature measurements in a magnetized expanding hydrogen plasma

et al. 2016

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Engeln, R. A. H. (2016). Electron density and temperature measurements in a magnetized expanding hydrogen plasma. Physical Review E, 94(2), [023201]. DOI: 10.1103/PhysRevE.94.023201 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. We report measurements of electron densities, n e , and temperatures, T e , in a magnetized expanding hydrogen plasma performed using Thomson scattering. The effects of applying an axial magnetic field and changing the background pressure in the plasma vessel on n e and T e along the expansion axis are reported. Magnetic field strengths (B field) up to 170 mT were applied, which are one order of magnitude larger than previously reported. The main effect of the applied B field is the plasma confinement, which leads to higher n e . At B fields larger than 88 mT the electron density along the expansion axis does not depend strongly on the magnetic field strength. However, T e is susceptible to the B field and reaches at 170 mT a maximum of 2.5 eV at a distance of 1.5 cm from the exit of the cascaded arc. To determine also the effect of the arc current through the arc, measurements were performed with arc currents of 45, 60, and 75 A at background pressures of 9.7 and 88.3 Pa. At constant magnetic field n e decreases from the exit of the arc along the expansion axis when the arc current is decreased. At 88.3 Pa n e shows a higher value close to the exit of the arc, but a faster decay along the expansion axis with respect to the 9.7 Pa case. T e is overall higher at lower pressure reaching a maximum of 3.2 eV at the lower arc current of 45 A. The results of this study complement our understanding and the characterization of expanding hydrogen plasmas.

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Thomson scattering experiments on a 100 MHz inductively coupled plasma calibrated by Raman scattering

Cited by 57 publications

References 9 publications

Steep plasma gradients studied with spatially resolved Thomson scattering measurements

Steep plasma gradients studied with spatially resolved Thomson scattering measurements

An active spectroscopical study on the plasma parameters of an ICP

Electron density and temperature measurements in a magnetized expanding hydrogen plasma

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