Two Q-switched Nd：YAG lasers at 1064 nm wavelength have been employed to produce plasmas on aluminum-based alloy in single- and collinear double-pulse laser induced breakdown spectroscopy （LIBS）. Time resolved tech...Two Q-switched Nd：YAG lasers at 1064 nm wavelength have been employed to produce plasmas on aluminum-based alloy in single- and collinear double-pulse laser induced breakdown spectroscopy （LIBS）. Time resolved technique was used for detecting emission sig- nal by spectrometer equipped with ICCD detector. The intensity calibration of spectral response was performed by using deuterium and tungsten halogen lamps. Time evolution of the plasma temperature and electron number density was investigated in single- and collinear double-pulse experiments. Based on the investigation of plasma parameters, the emission signal enhancement mechanism was discussed qualitatively.展开更多
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 H...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.展开更多
基金supported by National Natural Science Foundation of China(Nos.11274254,11364037,11064012)the JSPS-NRF-NSFC A3 Foresight Program in the field of Plasma Physics(No.11261140328)the International Scientic and Technologic Cooperative Project of Gansu Province,China(No.1104WCGA186)
文摘Two Q-switched Nd：YAG lasers at 1064 nm wavelength have been employed to produce plasmas on aluminum-based alloy in single- and collinear double-pulse laser induced breakdown spectroscopy （LIBS）. Time resolved technique was used for detecting emission sig- nal by spectrometer equipped with ICCD detector. The intensity calibration of spectral response was performed by using deuterium and tungsten halogen lamps. Time evolution of the plasma temperature and electron number density was investigated in single- and collinear double-pulse experiments. Based on the investigation of plasma parameters, the emission signal enhancement mechanism was discussed qualitatively.
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)
文摘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.
