Multilaser and high spatially resolved multipoint Thomson scattering system for the JT-60U tokamak

The design and operation performance of the latest ruby Thomson scattering system for the JT-60U are described, which includes many novel approaches to attain the repetitive measurement of 60 spatial points with high resolution (8 mm), precision, and reliability especially for a high temperature and large size tokamak device. A beam combiner composed of a polarizer and a Faraday rotator for two ruby lasers has provided the transient measurement with the minimum time interval of 2 ms in burst operation and the multitime-slice measurement with the repetition rate of 0.5 Hz in normal operation. A newly developed photodiode array detector with high repetitive ability of 1 ms has been used for the high temperature core plasma measurement. A quantitative alignment of collection fiber object field has been utilized for the reliable ne profile measurement. By using Rayleigh scattering light, an in situ inferring method for a coated viewing window transmission has been found to have an effect on the precise correc...