Optical computer aided tomography measurements of plasma uniformity in an inductively coupled discharge
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
Optical computer aided tomography (CAT) is being investigated as a potential in situ diagnostic for measuring plasma uniformity without making assumptions concerning the plasma symmetry. The presence of an opaque vacuum chamber wall severely limits the different directions from which optical emission measurements can be made of the plasma. The tomographic inversion problem with restricted optical access is being solved using Tikhonov regularization. The accuracy of this inversion process is investigated for several different observation geometries using theoretical test data generated from known distributions. Optical CAT is applied to an ICP-GEC plasma source, with all the measurements made through a single large 152 mm diameter window. Axially asymmetric plasma distributions are demonstrated as a function of gas flow rate and gas composition.
- OSTI ID:
- 21202311
- Journal Information:
- AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 449; ISSN 0094-243X; ISSN APCPCS
- Country of Publication:
- United States
- Language:
- English
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