High resolution Thomson scattering for Joint European Torus (JET)
- EFDA-CSU Culham, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)
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{sup 19} m{sup -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.
- OSTI ID:
- 20641184
- Journal Information:
- Review of Scientific Instruments, Vol. 75, Issue 10; Conference: 15. topical conference on high temperature plasma diagnostics, San Diego, CA (United States), 19-22 Apr 2004; Other Information: DOI: 10.1063/1.1787922; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); JET-EFDA Contributors; ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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