A high resolution multiposition Thomson scattering system for the Rijnhuizen Tokamak project

A high resolution multiposition Thomson scattering setup to measure the electron temperature (T-e) and density (n(e)) of a hot plasma is described. The system is operational at the Rijnhuizen Tokamak Project. Light from a high power pulsed ruby laser is scattered by the free plasma electrons and relayed to a Littrow polychromator for spectral analysis. The spectrally and spatially resolved light is detected by a GaAsP photocathode. The two-dimensional image is intensified and recorded with a charge-coupled device camera. T-e in the range of 50 eV-6 keV can be measured at 115 spatial elements of 2.6 mm length along the laser beam. The observation error is <6% at n(e)=2 X 10(19) m(-3) and smaller for higher n(e). The high resolution and accuracy enabled the observation of small scale structures in T-e and n(e). (C) 1997 American Institute of Physics.