On the capability of spectrally resolved optical emission tomography for the diagnostic of nonisothermal low-pressure technological plasmas

Schielke, W; Röttig, G; Bandlow, Ingo; Pickalov, V. V.; Ohl, A.

doi:10.1016/s0257-8972(97)00330-7

Cited by 4 publications

(2 citation statements)

References 6 publications

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“…where y and r are defined as in figure 11, and R is the radius of the emitting plasma. Abel inversion of intense lines in the emission spectrum has been used for tomographic spectroscopy of inductively coupled plasmas [27,28], and other reconstruction algorithms have been used to study emission from sputtering gas [29] and sputtered atoms [30] in the magnetron discharges, and from a glow discharge with an immersed substrate [31].…”

Section: Reconstruction Of Emission Profiles Using the Abel Transform...mentioning

confidence: 99%

A spatially resolved spectroscopic study of ionization in the planar magnetron discharge

Christou

Barber

2002

Plasma Sources Sci. Technol.

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Spatially resolved optical emission spectroscopy has been used to investigate the sputtering and ionization of titanium in a DC planar magnetron using argon as a sputtering gas. Maps of argon and titanium atomic and ionic emission have been obtained. Characteristic emission patterns have been identified and explained by the sputtering of atoms from the magnetron target and their subsequent ionization in the dense plasma at the magnetron target. The inverse Abel transformation was used to reconstruct plasma emission profiles, revealing that the non-uniform erosion profile at the magnetron target leads to a non-uniformity in plasma properties some distance into the discharge. An enhanced metal ionic content has been found in the plasma on the axis of symmetry of the discharge, and this has been explained by an enhanced lateral diffusion of metal ions arising from the change in momentum of sputtered metal during collisional ionization by metastable argon atoms.

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Section: Reconstruction Of Emission Profiles Using the Abel Transform...mentioning

confidence: 99%

A spatially resolved spectroscopic study of ionization in the planar magnetron discharge

Christou

Barber

2002

Plasma Sources Sci. Technol.

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“…So far, some reports of OES measurement have been coupled with the CT technique to provide spatial information of capacitively or inductively coupled plasmas operating at high frequencies. 17,18,[21][22][23] However, it should be noted that many optical fibers or image sensors cannot be placed without positional constraints. In other words, a need exists to develop techniques to obtain plasma spatial structures from a few viewpoints.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the spatial structure of multiline emission in a capacitively coupled plasma using tomographic reconstruction

Kyuzo,

Harada,

Izumi

et al. 2024

Jpn. J. Appl. Phys.

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By imaging a capacitively coupled plasma from multiple directions using telecentric lens cameras and optical bandpass filters, the spatial structure of emission at specific wavelengths was reconstructed using the Tikhonov–Phillips regularization method. Camera parameters, crucial for relating three-dimensional structures to two-dimensional images, were evaluated experimentally to avoid a complex analytical approach. Assuming an axisymmetric emission profile, 750.4 nm Ar and 585.2 nm Ne emissions from Ar/Ne mixture plasma were reconstructed. The pressure dependence of the reconstructed Ar profile showed a similar trend to that of the two-dimensional emission images. The spatial structure of the emission intensity ratio of Ne to Ar from the reconstructed Ar and Ne profiles agreed well with a spatial distribution of electron temperatures measured with a Langmuir probe.

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Three-dimensional analysis of microwave generated plasmas with extended planar laser-induced fluorescence

Stopper¹,

Lindner²,

Schumacher³

2007

Review of Scientific Instruments

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We present the development and application of a diagnostic system for the analysis of microwave generated low-pressure plasmas, which might also be used for the investigation of the edge regions in magnetically confined fusion plasmas. Our method uses planar laser-induced fluorescence, which is produced by excitation of neutral metastable atoms through a short, intense, pulsed laser. The beam expansion optics consist of an uncommon setup of four lenses. By controlled shifting of an element of the optics sideways, the location of the laser sheet in the plasma is scanned perpendicular to the excitation plane. Together with a spectrometer observing different observation volumes along the beam path, we are able to map absolute three-dimensional (3D) population density distributions of the metastable ((2)P(12) (o)) 3s[12](0) (o) state of Ne I in an electron cyclotron resonance heating (ECRH) plasma. This optical tomography system was used to study the influence of the microwave power and mode on the spatial structure of the plasma. The results show that the population density of the neutral neon in this metastable state is found to be in the range of 10(16) m(-3), and that its spatial distribution is associated with the 3D structure of the magnetic field. We also report that the spatial distribution strongly varies with the mode structure, which depends on the microwave power.

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On the capability of spectrally resolved optical emission tomography for the diagnostic of nonisothermal low-pressure technological plasmas

Cited by 4 publications

References 6 publications

A spatially resolved spectroscopic study of ionization in the planar magnetron discharge

A spatially resolved spectroscopic study of ionization in the planar magnetron discharge

Evaluation of the spatial structure of multiline emission in a capacitively coupled plasma using tomographic reconstruction

Three-dimensional analysis of microwave generated plasmas with extended planar laser-induced fluorescence

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