Tokamak exhaust is an important part of the deuterium-tritium fuel cycle system in fusion reactions.In this work,we present a laser-induced breakdown spectroscopy(LIBS)-based method to monitor the gas compositions from the exhaust system in the tokamak device.Helium(He),a main impurity in the exhaust gas,was mixed with hydrogen(H2)in different ratios through a self-designed gas distribution system,and sealed into a measurement chamber as a standard specimen.A 532 nm wavelength laser pulse with an output power of 100 mJ was used for plasma excitation.The time-resolved LIBS is used to study the time evolution characteristics of the signal strength,signal-to-background ratio(SBR),signal-to-noise ratio(SNR)and relative standard deviation(RSD)of the helium and hydrogen characteristic lines.The Boltzmann two-line method was employed to estimate the plasma temperature of laser-induced plasma(LIP).The Stark-broadened profile of He I 587.56 nm was exploited to measure the electron density.From these studies,an appropriate time was determined in which the low RSD％was consistent with the high signal-to-noise ratio.The He I587.56 nm and Hα emission lines with good signal-to-noise ratio were extracted from the spectrum and used in the external standard method and internal standard method for quantitative analysis.The test results for mixed gas showed that the average relative error of prediction was less than 11.15％,demonstrating the great potential of LIBS in detecting impurities in plasma exhaust gas.

Yaxiong HE;Tao XU;Yong ZHANG;Chuan KE;Yong ZHAO;Shu LIU

School of Physics and Energy,Fujian Normal University,Fuzhou 350117,People's Republic of China;Center for Superconducting and New Energy Research and Development,Southwest Jiaotong University,Chengdu 610031,People's Republic of China;Fujian Provincial Collaborative Innovation Center for Advanced High-Field Superconducting Materials and Engineering,Fuzhou 350117,People's Republic of China;Shandong Dong Yi Optoelectronic Instrument Co.,Ltd,Yantai 264670,People's Republic of China;Technical Center for Industrial Product and Raw Material Inspection and Testing,Shanghai Customs,Shanghai 200135,People's Republic of China

等离子体科学和技术（英文版）

[1]Yaxiong HE;Tao XU;Yong ZHANG;Chuan KE;Yong ZHAO;Shu LIU-.Quantitative analysis and time-resolved characterization of simulated tokamak exhaust gas by laser-induced breakdown spectroscopy)[J].等离子体科学和技术（英文版）,2022(04):188-197

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