Abstract: The nanosecond laserinduced brass plasma spectra were obtained by using a selfbuilt laserinduced breakdown spectroscopy (LIBS) experimental device at room temperature and atmospheric pressure. We studied the evolution of the Zn plasma spectrum in the emission spectrum with 150—3 000 ns gate delay of the intensified chargecoupled device (ICCD), and calculated the evolution law of electron temperature and electron density of the plasma with ICCD gate delay by using the Stark broadening coefficient and energy level transition parameters. The experimental results show that when the ICCD gate delay is 150—500 ns, the spectrum shows a strong continuous spectrum at the initial stage. With the increase of ICCD gate delay, the linear characteristic lines of Zn atoms are gradually highlighted on the continuous spectrum. The spectral intensity of the characteristic line reaches maximum when the ICCD gate delay is 500 ns. With the increase of the ICCD gate delay, the spectral intensity gradually decreases, and the characteristic line signal of the plasma disappears when the ICCD gate delay is 3 000 ns. The spectral intensity and electron temperature are consistent with the change of ICCD gate delay, the electron density and the full width half maximum (FWHM) of ZnⅠ(481.0 nm) spectral line is close to exponential fitting with the change of ICCD.

Key words:  , spectral intensity, electron temperature, electron density, ICCD gate delay,  , full width half maximum (FWHM)