中文摘要：

为了提高激光诱导击穿光谱质量,采用Nd∶YAG激光器输出的纳秒脉冲激光激发产生土壤等离子体,采用光栅光谱仪和光电检测系统记录了元素谱线AlⅠ394.401nm,BaⅠ455.403nm,FeⅠ430.791nm和TiⅠ498.173nm的辐射强度和信背比,研究了激光脉冲重复频率（5,10和15Hz）对等离子体辐射特性的影响。实验结果表明,在相同的激光输出能量条件下,当采用15Hz的激光脉冲重复频率时,元素Al,Ba,Fe和Ti的谱线强度要比5Hz时的分别提高50.94%,112.7%,107.46%和99.38%,光谱信背比分别提高15.16%,24.08%,40.26%和72.06%。通过测量等离子体参数,解释了激光脉冲重复频率对等离子体辐射特性的影响机理。

英文摘要：

To improve the quality of laser-induced breakdown spectroscopy,nanosecond pulse laser generated by Nd∶YAG laser was used to excite soil sample.The intensity and signal-to-background ratio of Al Ⅰ 394.401 nm,Ba Ⅰ 455.403 nm,Fe Ⅰ 430.791 nm and Ti Ⅰ 498.173 nm were observed using a grating spectrometer and a photoelectric detection system.The effects of laser shot frequency（5,10 and 15 Hz）on the radiation characteristics of laser-induced plasma was studied.The experimental results show that as compared with the laser shot frequency of 5 Hz,the spectral line intensity of Al,Ba,Fe and Ti increased by about 50.94%,112.7%,107.46%,and 99.38% at 15 Hz respectively under the same laser energy,while the spectral signal-to-background ratio increased byabout 15.16%,24.08%,40.26% and 72.06% respectively.The effects mechanism of the laser shot frequency on radiation characteristics of plasma is explained by measuring plasma parameters.