This title appears in the Scientific Report :
2017
Please use the identifier:
http://dx.doi.org/10.1063/1.4963163 in citations.
Please use the identifier: http://hdl.handle.net/2128/16714 in citations.
Alignment and absolute wavelength calibration of imaging Bragg spectrometers
Alignment and absolute wavelength calibration of imaging Bragg spectrometers
In the present and the next generation of fusion devices, imaging Bragg spectrometers are key diagnostics to measure plasma parameters in the hot core, especially ion temperature and plasma rotation. The latter quantities are routinely obtained using the Doppler-width and -shift of the emitted spect...
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Personal Name(s): | Bertschinger, G. (Corresponding author) |
---|---|
Marchuk, O. / Barnsley, R. | |
Contributing Institute: |
Plasmaphysik; IEK-4 |
Published in: | Review of scientific instruments, 87 (2016) 11, S. 11E343 |
Imprint: |
[S.l.]
American Institute of Physics
2016
|
DOI: |
10.1063/1.4963163 |
Document Type: |
Journal Article |
Research Program: |
Plasma-Wall-Interaction |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://hdl.handle.net/2128/16714 in citations.
In the present and the next generation of fusion devices, imaging Bragg spectrometers are key diagnostics to measure plasma parameters in the hot core, especially ion temperature and plasma rotation. The latter quantities are routinely obtained using the Doppler-width and -shift of the emitted spectral lines, respectively. Line shift measurements require absolute accuracies Δλ/λ of about 10 ppm, where λ-is the observed wavelength. For ITER and the present fusion devices, spectral lines of He-and H-like argon, iron, and krypton as well as Ne-like tungsten are foreseen for the measurements. For these lines, Kα lines can be found, some in higher order, which fit into the narrow energy window of the spectrometers. For arbitrary wavelength settings, Kα lines are also used to measure the miscut of the spherical crystals; afterwards the spectrometers can be set according to the geometrical imaging properties using coordinate measurement machines. For the spectrometers measuring Lyα lines of H-like ions, fluorescence targets can provide in situ localized calibration lines on the spectra. The fluorescence targets are used best in transmission and are excited by the thermal x-ray radiation of the plasma. An analytic theory of fluorescence is worked out. |