In-Situ Wavelength Calibration of Fast-Response Extreme Ultraviolet Spectrometers on Experimental Advanced Superconducting Tokamak and Its Application
YAO Li-ming1, 2, ZHANG Ling3*, XU Zong4, 5, YANG Xiu-da6, WU Cheng-rui6, ZHANG Rui-rui3, YANG Fei3, WU Zhen-wei3, YAO Jian-ming3, GONG Xian-zu3, HU Li-qun3
1. Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, Hefei 230026, China
2. Hefei Insititutes of Physical Science, University of Chinese Academy of Sciences, Hefei 230026, China
3. Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230026, China
4. Advanced Energy Research Center, Shenzhen University, Shenzhen 518060, China
5. Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
6. Science Island Branch of Graduate School, Graduate School of University of Science and Technology of China, Hefei 230026, China
Abstract：In this work，the in-situ wavelength calibration method for the newly installed fast-time-response Extreme Ultraviolet (EUV) Spectrometers on EAST is introduced and the result and its application are described. Both of the spectrometers are grazing incidence flat-field spectrometers with temporal resolution of 5 ms·frame-1. The two spectrometer works at 20～500 and 10～130 Å respectively, and wavelength scanning is done by moving the detector along the focal plane. The impurity behavior is monitored for EAST operation with observed EUV spectrum and the calculated time evolution of impurity line intensity. High spectral resolution and capability of accurate wavelength measurement is required for line identification of EUV spectra from high-Z impurities especially tungsten, due to the complexity of the spectrum composition. Exact wavelength calibration is therefore one of the key techniques for the tungsten spectroscopy diagnosis and tungsten behavior study. Emission lines from hydrogen-, helium-, lithium- and beryllium-like low- and medium-Z impurities, e. g., O Ⅷ 18.97 Å, O Ⅶ 21.60 Å, CⅥ 33.73 Å, CⅥ 40.27 Å, LiⅢ 113.9 Å, LiⅢ 135.0 Å, LiⅡ 199.28 Å, ArⅩⅤ 221.15 Å, HeⅡ 256.317 Å, HeⅡ 303.78 Å, ArⅩⅥ 353.853 Å, CⅣ 384.174 Å, and their 2nd even 3rd order emission lines are used to perform the in-situ wavelength calibration for the two EUV spectrometers in the whole wavelength range. Line identification is then carried out with the result of wavelength calibration. It is found that for most of the emission lines the difference between observed wavelength and their standard value is very small, e. g., ≤0.08 Å and ≤0.03 Å for the spectrometer working at 20～500 and 10～130 Å, respectively. A module for the in-situ wavelength calibration is developed and is inserted into the interactive software developed for real-time data upload, which realizes a real-time upload of the calibrated EUV spectra and calculated time-evolution of line intensity to the EAST data server. Meanwhile, the interactive software for spectrum analysis and visualization is also developed, combining with the use of the routine EAST data visualization tools, the quasi real-time analysis, reading and visualization of EUV spectrometer data are realized during the EAST operation.
姚黎明，张 凌，许 棕，杨秀达，吴承瑞，张睿瑞，杨 飞，吴振伟，姚建铭，龚先祖，胡立群. EAST快速极紫外光谱仪波长的原位标定及其应用[J]. 光谱学与光谱分析, 2019, 39(08): 2645-2650.
YAO Li-ming, ZHANG Ling, XU Zong, YANG Xiu-da, WU Cheng-rui, ZHANG Rui-rui, YANG Fei, WU Zhen-wei, YAO Jian-ming, GONG Xian-zu, HU Li-qun. In-Situ Wavelength Calibration of Fast-Response Extreme Ultraviolet Spectrometers on Experimental Advanced Superconducting Tokamak and Its Application. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2019, 39(08): 2645-2650.
