A high spatial resolution imaging Thomson scattering diagnostic system was developed in ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences). After about one month trial running on the superconducting HT-7 (Hefei Tokamak-7) tokamak, the system was proved to be capable of measuring plasma electron temperature. The system setup and data calibration are described in this paper and then the instrument function is studied in detail, as well as the measurement capability, an electron temperature of 50 eV to 2 keV and density beyond 1 × 10(19) m(-3). Finally, the data processing method and experimental results are presented.

A visible light imaging Thomson scattering (VIS-TVTS) diagnostic system has been developed for the measurement of plasma electron temperature on the HT-7 tokamak. The system contains a Nd:YAG laser (λ = 532 nm, repetition rate 10 Hz, total pulse duration ≈ 10 ns, pulse energy > 1.0 J), a grating spectrometer, an image intensifier (I.I.) lens coupled with an electron multiplying CCD (EMCCD) and a data acquisition and analysis system. In this paper, the measurement capability of the system is analyzed. In addition to the performance of the system, the capability of measuring plasma electron temperature has been proved. The profile of electron temperature is presented with a spatial resolution of about 0.96 cm (seven points) near the center of the plasma.

An imaging Thomson scattering system has been designed and built to perform the spatial-resolution-oriented plasma electron temperature and density measurements, which incorporates a second generation image intensifier and an EMCCD as a detection system. In general, the characteristic of weak scattering of radiation is the most concern in Thomson scattering systems. Therefore, it's quite essential for the initial system design to avoid further loss of the amount of radiant power transferred from the source to the detector, and to perform the detection capability verification based on the designed setup. This paper will focus on three points. Firstly, The key design parameters including magnification and f number of the collection lens, the diameter and NA of the fiber, the entrance and exit slit area and f number of the spectrometer are designed interactively to maximize light throughput, with also beam quality taken into account. Then, the system setup is described and the expected photon number per pulse per scattering length is calculated. Finally, from the comparison between the measured radiation photons of a standard lamp and the calculated photons based on the designed condition, with both spatial binning and EM gain performed, the capability of the detection system is verified.

A new wide-angle endoscope for visible light observation on the Experimental Advanced Superconducting Tokamak (EAST) has been recently developed. The head section of the optical system is based on a mirror reflection design that is similar to the International Thermonuclear Experimental Reactor-like wide-angle observation diagnostic on the Joint European Torus. However, the optical system design has been simplified and improved. As a result, the global transmittance of the system is as high as 79.6% in the wavelength range from 380 to 780 nm, and the spatial resolution is <5 mm for the full depth of field (4000 mm). The optical system also has a large relative aperture (1:2.4) and can be applied in high-speed camera diagnostics. As an important diagnostic tool, the optical system has been installed on the HT-7 (Hefei Tokamak-7) for its final experimental campaign, and the experiments confirmed that it can be applied to the investigation of transient processes in plasma, such as ELMy eruptions in H-mode, on EAST.