Feasibility of non-thermal helium measurements with charge exchange spectroscopy on ITER

TitleFeasibility of non-thermal helium measurements with charge exchange spectroscopy on ITER
Publication TypeJournal Article
Year of Publication2012
AuthorsA. Kappatou, E. Delabie, R.JE Jaspers, M.G von Hellermann
JournalNuclear Fusion
Volume52
Issue4
Pagination043007
Date PublishedApr
Type of ArticleArticle
ISBN Number0029-5515
KeywordsALPHA-PARTICLES, collective Thomson scattering, diagnostics, PLASMAS, REQUIREMENTS, SPECTRA, TFTR
Abstract

The use of active charge exchange recombination spectroscopy (CXRS) as a diagnostic for fusion-produced alpha particles on ITER is constrained by the signal-to-noise ratio, which is determined by the intensity of the line of interest, the optical throughput of the diagnostic, the neutral beam penetration, and the intensity of bremsstrahlung radiation. The CX spectral line for fast ions has been modelled together with the expected background emission and we present the signal-to-noise ratios calculated as a function of the diagnostic design parameters. Combining the CXRS data from both the heating and the diagnostic neutral beams on ITER, information on fast ions with energies up to 1 MeV can be obtained for the parameters of the ITER core CXRS diagnostic design. To achieve this, energy binning of the signal is used (100 keV bins or larger), in order to improve the signal-to-noise ratio, with a time resolution of 2 s. The time resolution of the measurement can be improved using a higher throughput spectrometer, but this is ultimately limited by the amount of light from the neutral beam that can be collected. Despite the challenges and the fact that the results are not as optimistic as previously assumed, it is concluded that useful information on fast helium density profiles can be obtained using CXRS on ITER.

DOI10.1088/0029-5515/52/4/043007
Division

FP

Department

PDG

PID

3339e7941d61c322cf1793e63389b2bc

Alternate TitleNucl. Fusion

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