Error analysis of Rijnhuizen tokamak project Thomson scattering data

TitleError analysis of Rijnhuizen tokamak project Thomson scattering data
Publication TypeJournal Article
Year of Publication1999
AuthorsM.NA Beurskens, C.J Barth, C.C. Chu, N.JL Cardozo
JournalReview of Scientific Instruments
Date PublishedApr
ISBN Number0034-6748

At the Rijnhuizen tokamak project a double pulse multiposition Thomson scattering diagnostic has been operational since 1996. It has been installed for the study of small scale structures in electron temperature (T-e) and density (n(e)). This diagnostic measures T-e and n(e) with high spatial resolution (3 mm full width at half maximum, i. e., 2% of the minor radius) and high accuracy (3%-4% of T-e and 2%-3% of n(e) in the range of 50 eV-6 keV and n(e) 5 x 10(19) m(-3).) In this article an extensive error analysis is performed on both statistical and systematic deviations. It is found that the instrument function of the detection branch has a smoothing effect on the noise. This reduces the statistical error on the T-e and n(e) measurements on each spatial position, because the resolution of the instrument is oversampled. The long tail of the instrument profile of the entire diagnostic has a significant effect on the systematic deviations in the T-e and n(e) determination. However, it does not affect the relative size of the small scale structures on T-e and n(e), and for this this reason does not hamper the study of these structures. (C) 1999 American Institute of Physics. [S0034-6748(99)02704-5].



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