1 August 1990 High-power ruby and alexandrite lasers for LIDAR-Thomson scattering diagnostics
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Proceedings Volume 1277, High-Power Solid State Lasers and Applications; (1990) https://doi.org/10.1117/12.20594
Event: The International Congress on Optical Science and Engineering, 1990, The Hague, Netherlands
By combining the time-of-flight or LIDAR principle with a Thomson backscatter diagnostic, spatial profiles of the electron temperature and density can be measured with a single set of detectors for all spatial points. The technique was demonstrated for the first time on the JET tokamak and has been in routine operation since July 1987. Originally a ruby laser (3 J pulse energy, 300 Ps pulse duration, 0.5 Hz repetition rate) was used together with a 700 MHz bandwidth detection and registration system which yielded a spatial resolution of about 12 cm. A large filter spectrometer with 6 spectral channels covering the wavelength range 400 - 800 nm gives a dynamic range for the temperature measurements of 0.2-20 keV. The original system is described, examples of measurements are given and compared with the results of other diagnostics. The system is being upgraded to make measurements at 10 Hz and a major component of the new system is an Alexandrite laser (1-2 J pulse energy, 350+1-50 ps pulse duration, 10 Hz repetition rate) which is currently being constructed. The new laser and other technological improvements being incorporated into the upgraded diagnostic will also be described.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
C. Gowers, A. Gadd, Kurt Hirsch, P. Nielsen, H. Salzmann, "High-power ruby and alexandrite lasers for LIDAR-Thomson scattering diagnostics", Proc. SPIE 1277, High-Power Solid State Lasers and Applications, (1 August 1990); doi: 10.1117/12.20594; https://doi.org/10.1117/12.20594


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