High-speed VUV spectroscopy for edge impurity line emission measurements in HL-2A tokamak  

作　　者：Dianlin ZHENG Kai ZHANG Zhengying CUI Ping SUN Chunfeng DONG Ping LU Bingzhong FU Zetian LIU Zhongbing SHI Qingwei YANG 郑典麟;张凯;崔正英;孙平;董春凤;卢平;傅炳忠;刘泽田;石中兵;杨青巍(Southwestern Institute of Physics, Chengdu 610041, People's Republic of China)

机构地区：Southwestern Institute of Physics,Chengdu 610041,People＇s Republic of China

出　　处：《Plasma Science and Technology》2018年第10期75-83,共9页等离子体科学和技术（英文版）

基　　金：partly supported by National Natural Science Foundation of China (Nos. 11375057 and 11505051);the National Magnetic Confinement Fusion Program of China (Nos. 2014GB108003 and 2015GB104003)

摘　　要：A 20 cm focal length normal incidence vacuum ultraviolet （VUV_20 cm） monochromator with a fast time response has been developed for measuring edge impurity line emission in the wavelength range of 300-2000 A on an HL-2A tokamak. An aberration corrected concave holographic grating with 1200 grooves/mm is adopted in the monochromator, which provides a wavelength dispersion of 40 A mm-1. The aperture is f/4.5. A channel electron multiplier is used as a detector. The time resolution of the system is 17 μs. Wavelength calibration of the system has been done by using a hollow cathode light source in the laboratory with helium and argon gases. The obtained signals of helium and argon spectra are very strong since the inner surface of the monochromator vacuum chamber is blackened and the stray light level is then significantly reduced. The optical property of the system has been examined by scanning the width of the entrance and exit slits. The system is then installed at the mid-port of the HL-2A tokamak and typical line emissions from the HL-2A plasma are measured. Time behaviors of edge impurity line emissions are observed with the fast time response system in different plasma confinement regimes, especially in the H-mode discharges. The result shows that the VUV_20 cm system works very well to measure the edge impurity line emissions in the edge localized modes phase of H-mode discharges.A 20 cm focal length normal incidence vacuum ultraviolet （VUV_20 cm） monochromator with a fast time response has been developed for measuring edge impurity line emission in the wavelength range of 300-2000 A on an HL-2A tokamak. An aberration corrected concave holographic grating with 1200 grooves/mm is adopted in the monochromator, which provides a wavelength dispersion of 40 A mm-1. The aperture is f/4.5. A channel electron multiplier is used as a detector. The time resolution of the system is 17 μs. Wavelength calibration of the system has been done by using a hollow cathode light source in the laboratory with helium and argon gases. The obtained signals of helium and argon spectra are very strong since the inner surface of the monochromator vacuum chamber is blackened and the stray light level is then significantly reduced. The optical property of the system has been examined by scanning the width of the entrance and exit slits. The system is then installed at the mid-port of the HL-2A tokamak and typical line emissions from the HL-2A plasma are measured. Time behaviors of edge impurity line emissions are observed with the fast time response system in different plasma confinement regimes, especially in the H-mode discharges. The result shows that the VUV_20 cm system works very well to measure the edge impurity line emissions in the edge localized modes phase of H-mode discharges.

关 键 词：VUV monochromator CEM detector wavelength calibration impurity line emission H-mode plasmas 

分 类 号：TL631.24[核科学技术—核技术及应用] TN304.12[电子电信—物理电子学]