Sketch of the TV Thomson scattering system on HT-7 tokamak. This system is composed of high-energy laser, mirrors, grating spectrometer, image intensifier, EMCCD, and data acquisition system.
The three-dimensional scattering signal of TVTS system. The effective pixels of EMCCD are 1004 × 1002 and the reciprocal of line dispersion is 0.38 nm/pixel, approximately.
Relative efficiency curve obtained with the working parameters. This sensitivity factor includes the effect of lens, fiber bundle, optical spectrometer, image intensifier, coupling lens, and EMCCD. The relative efficiency is higher between 500 nm and 650 nm.
Instrument broadening in blue and Gaussian fitting function in red. The full width at half maximum (FWHM) of instrument function is about 10 nm which corresponds to the Doppler broadening of scattering electron at 16 eV.
Transmissivity of the notch filter in blue and scattering spectral density of different temperatures in other colors. The thick lines of scattering spectrum include calculation of the transmissivity and the thin lines do not include the transmissivity, respectively. The measurable minimum electron temperature is about 50 eV.
Thomson scattering signal in blue and corresponding fitting function curve in green.
The profile of electron temperature measured by TVTS system. The plasma current is in the region of 150 kA and the central line-averaged plasma density is about 2.6 × 1019 m−3.
Parameters table of the notch filter.
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