Promt - a Multiposition Thomson-Scattering System for Rtp

PROMT is a system for multiposition Thomson scattering in use at the Rijnhuizen Tokamak Project tokamak. Light from a ruby laser is scattered by the free electrons in the plasma and is collected along a vertical chord of 180 mm. Electron temperature and density profiles can be measured resolving up to 36 spatial elements. Scattered light is spectrally analyzed by a Littrow polychromator and subsequently detected with an intensified charge coupled device camera. At densities of 2 X 10(19) m-3 electron temperatures in the range of 50 eV-3 keV can be measured with an accuracy of approximately 5 %.