Calibration of the toroidal Charge eXchange Recombination Spectroscopy system on EAST

The toroidal Charge exchange Recombination Spectroscopy (CXRS) diagnostic was recently deployed on EAST to measure plasma temperature, velocity and impurity density profiles. For spatial calibration, bacldit fiber images were projected to a plane that intersected with the neutral beam centerline to accurately identify the measuring positions and angles. Wavelength calibration was performed using a neon lamp, which was also used to measure dispersions and instrumental functions of the spectrometers. To exclude the effect of fluctuating wavelength caused by ambient temperature, one fiber was fed by a standard lamp during the experiments to provide real-time wavelength calibration, which was complemented by the intrinsic impurity line emissions. Intensity calibration was done using an integrating sphere lamp. It was shown that the uncertainty of the position calibration was less than 10 mm, while the angle and the wavelength was <0.5 degrees and <0.005 nm, respectively. These calibration results were applied in the data analysis to provide the plasma temperature, velocity and impurity density. Preliminary central carbon temperature was compared to argon temperature measured by the X-ray crystal spectrometer and agreements were observed. (c) 2015 Elsevier B.V. All rights reserved.