High resolution Thomson scattering for Joint European Torus (JET)

TitleHigh resolution Thomson scattering for Joint European Torus (JET)
Publication TypeJournal Article
Year of Publication2004
AuthorsR. Pasqualotto, P. Nielsen, C. Gowers, M. Beurskens, M. Kempenaars, T. Carlstrom, D. Johnson
JournalReview of Scientific Instruments
Volume75
Number10
Pagination3891-3893
Date PublishedOct
Type of ArticleArticle
ISBN Number0034-6748
Accession NumberISI:000224755900153
KeywordsSYSTEM
Abstract

A Thomson scattering system is being developed for Joint European Torus with 15 mm spatial resolution and a foreseen accuracy for temperature better than 15% at a density of 10(19) m(-3). This resolution is required at the internal transport barrier and edge pedestal and it can not be fully achieved with the present light detection and ranging systems. The laser for this system is Nd:YAG, 5 Joule, 20 Hz. Scattering volumes from R=2.9 m to R=3.9 m are imaged onto 1 mm diameter fibers, with F/25 collection aperture. Two fibers are used per scattering volume. Using optical delay lines, three scattering volumes are combined in each of the 21 filter polychromators. The signals are recorded with transient digitizers, which allow the combined time delayed signals to be resolved. Knowledge of the time delay between signals allows the use of correlation techniques in determining signal levels. The ac output of the amplifier is used, which tolerates a higher level of background signal without affecting dynamic range. The noise resulting from plasma light is determined directly. (C) 2004 American Institute of Physics.

URL<Go to ISI>://000224755900153
Division

Fusion Physics

Department

Instrumentation development

PID

51c3af67e2d4ab1331705f803dae01d3

Alternate TitleRev. Sci. Instrum.

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