IR Thomson Scattering Systems for Measurement of Ne, TE Profiles in open Traps
| Autor: | Leonid Vyacheslavov, V. F. Gurko, Oleg Meshkov, V. F. Zharov |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Physics
Interference filter business.industry Thomson scattering 020209 energy Amplifier General Engineering 02 engineering and technology Plasma Laser Avalanche photodiode 01 natural sciences Noise (electronics) 010305 fluids & plasmas law.invention Optics Lidar law 0103 physical sciences 0202 electrical engineering electronic engineering information engineering business |
| Zdroj: | Fusion Technology. 35:422-426 |
| ISSN: | 0748-1896 |
| DOI: | 10.13182/fst99-a11963898 |
| Popis: | Two laser scattering systems based on Nd-glass laser and avalanche photodiodes are proposed. First system is designed for observation of radial profiles of the electron plasma density and temperature. Each of its 2-4 spectral modules consists of 25 spatial channels and includes a bandpass interference filter, low F-number camera lens, and 25-channel linear array of the avalanche photodiodes followed by amplifiers and ADCs. Every of 25 spatial channel can view the plasma volume with an adjustable length of 1.5-15 mm along the radius of a trap. In the IR spectral region the plasma background radiation is small and the main source of noise is the amplifier noise, which permits in this case observation of a plasma of a density of 10 12 cm -3 with the S/N >60. The second system is intended for measuring the longitudinal n e and T e profiles and uses the LIDAR technique, which is more suitable for open traps than for large tokomaks due to considerable larger axial length. A relative simple short pulse version of the probe laser (0.5-1 ns, 10 J), commercially available high speed APD-preamplifier modules, and ADC, as well as very high contrast-interference filters can provide longitudinal measurements with the spatial resolution 1≤.20 cm and S/N > 40 for n e ≥ 10 12 cm -3 The probe laser (30J, 8 ns, 1.06 μm, 0.2 mrad ) and the prototype of a single spectral module for radial measurements have been developed an used in an experiment. |
| Databáze: | OpenAIRE |
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