High sensitivity imaging Thomson scattering for low temperature plasma

• Published in: Review of scientific instruments 2008-01, Vol.79 (1), p.013505-013505-8
• Main Authors: van der Meiden, H. J., Al, R. S., Barth, C. J., Donné, A. J. H., Engeln, R., Goedheer, W. J., de Groot, B., Kleyn, A. W., Koppers, W. R., Lopes Cardozo, N. J., van de Pol, M. J., Prins, P. R., Schram, D. C., Shumack, A. E., Smeets, P. H. M., Vijvers, W. A. J., Westerhout, J., Wright, G. M., van Rooij, G. J.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALUMINIUM; BEAMS; DOPED MATERIALS; ELECTRON DENSITY; ELECTRON TEMPERATURE; EV RANGE; GARNETS; IMAGE INTENSIFIERS; ION TEMPERATURE; LASERS; NEODYMIUM; PLASMA; PLASMA DENSITY; SENSITIVITY; SPATIAL RESOLUTION; SPECTROMETERS; THOMSON SCATTERING; VISIBLE RADIATION; YTTRIUM
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.2832333

A highly sensitive imaging Thomson scattering system was developed for low temperature ( 0.1 - 10 eV ) plasma applications at the Pilot-PSI linear plasma generator. The essential parts of the diagnostic are a neodymium doped yttrium aluminum garnet laser operating at the second harmonic ( 532 nm ) , a laser beam line with a unique stray light suppression system and a detection branch consisting of a Littrow spectrometer equipped with an efficient detector based on a "Generation III" image intensifier combined with an intensified charged coupled device camera. The system is capable of measuring electron density and temperature profiles of a plasma column of 30 mm in diameter with a spatial resolution of 0.6 mm and an observational error of 3% in the electron density ( n e ) and 6% in the electron temperature ( T e ) at n e = 4 × 10 19 m − 3 . This is achievable at an accumulated laser input energy of 11 J (from 30 laser pulses at 10 Hz repetition frequency). The stray light contribution is below 9 × 10 17 m − 3 in electron density equivalents by the application of a unique stray light suppression system. The amount of laser energy that is required for a n e and T e measurement is 7 × 10 20 ∕ n e J , which means that single shot measurements are possible for n e > 2 × 10 21 m − 3 .