The Calibration Of The Toroidal CXRS Diagnostic In EAST

This thesis mainly studies the calibrations of the toroidal Charge eXchange Recombination Spectroscope (CXRS) diagnostic systems on the Experimental Advanced Superconducting Tokamak (EAST). The calibrations can be divided into three parts, such as in situ spatial calibration, wavelength calibration and relative/absolute intensity calibration. In order to obtain more accurate calibration results, on the one hand before the EAST experiment these calibrations have been finished. On the other hand, combining the characteristics of plasma during the experiment the CXRS diagnostic system been calibrated the second time and the results were compared to the first time to make sure the outcome is precise. Comparing the experiment results between CXRS diagnostic and the other diagnostic, it is found that the results from CXRS diagnostic is accurate.The introduction of the EAST and its main components illustrates its function and objective. The environment and work platform of the CXRS diagnostic system is clear. Starting from the principle of CXRS diagnostic, some inherent problems of the diagnostic are put forward and some attentions in the experiment are emphasized.The in situ spatial calibration was finished in the vacuum chamber after the light collecting lens had been installed in the EAST. Using the geometric measurement in the vacuum chamber, the observation space position and the angle between every line of sight and the tangential NBI was obtained. In order to improve the accuracy of spatial calibration, the spatial calibration has been finished with the help of mechanical arm in the next plan of EAST experiment in2015. The absolute position in the tokamak of every point in the line of sight can be got directly by the arm.The wavelength calibration is to get the wavelength of spectral lines measured by the CCD detector. This work studied from the time when the spectrometer was testing. As the CXRS diagnostic system requires to realize wavelength scanning, the grating in the spectrometer must be fixed on the turntable. In order to find out the relationship between the rotation angle of the grating and the wavelength of the spectral lines in the CCD detector the wavelength calibration must be finished. Due to the diffraction of the light coming from the entrance slit, the image in the CCD detector will be curved. So each observation sight of the fiber should be calibrated separately after the diagnostic system been built well in the EAST. During the EAST experiment in order to avoid the wavelength changeable as the diagnostic system especial the light collected lens be affected by the environment, three fibers are shine by the rare elements lights which is used for real-time calibration.The intensity calibration started after the spatial calibration and wavelength calibration had been finished. A calibration platform was designed specifically for the intensity calibration. The integrating sphere light source was put on the platform and each observation fiber should be perpendicular to the light source. For the intensity of the integrating sphere light source has been known, the absolute intensity correction coefficient of each fiber can be calculated easily by the CCD detector counts and the exposure time.During the EAST experiment the calibrations of the system were checked by combining the preliminary experiment results from the CXRS diagnostic system. Firstly, the angle between every line of sight and the tangential NBI were calculated from the Doppler shift D alpha lines observed by the CCD detector, it was shown that the calculated results from different shot and different spectrometer and the calibration results are in good harmony. Then the background lines emitted from the plasma can be used as reference wavelength and this makes wavelength calibration more precise. Comparing the theoretical calculation of bremsstrahlung radiation intensity and the CXRS measurement, it was found that the trend is consistent. In this thesis, an attempt of getting the density of C6+was making by combining the CXRS diagnostic and the DC-BES (Beam Emission Spectroscopy) diagnostic. From the results of the first attempt, it is found there are many problems should be researched deeply.Lastly, this thesis compares the plasma temperature measuring by CXRS diagnostic and X-ray Crystal Spectroscopy (XCS) diagnostic, it is found the results are very consistent. This proves the CXRS diagnostic system is accuracy.