激光诱导土壤等离子体光谱辐射实验参数优化（英文）

Optimization of experimental parameters of laser induced soil plasma spectral radiation

采用激光诱导击穿光谱法(LIBS)对土壤进行了研究。激光器采用的是Nd:YAG脉冲激光器,激光器的输出波长是1 064 nm,脉宽是5.82 ns,激光聚焦在土壤表面产生激光诱导等离子体,通过优化实验参数(ICCD延时、脉冲能量、ICCD门宽、脉冲频率、谱图积累次数)对Ca II 393.37 nm和Ca II 396.37 nm两条特征谱线强度及信背比的影响,确定实验最佳条件是ICCD延时1μs,激光能量50 m J,ICCD门宽3.5μs,脉冲频率1 Hz,谱图积累次数100次。在最优实验条件下计算等离子体参数,得出土壤中的等离子体电子温度是11 604 K,土壤的等离子体电子密度是5.155×1016 cm-3,经过计算,土壤样品满足LTE条件。这说明,以上关于土壤样品的等离子体参数计算结果是真实有效的。

Laser induced breakdown spectroscopy(LIBS)was employed to investigate the soil.LIBS analyses were performed with Nd:YAG laser operating at1064nm,5.82ns pulse duration.The spectral lines of Ca II393.37nm and Ca II396.85nm were selected as the analytical lines for optimizing the experimental parameters(ICCD delay,laser energy,ICCD gate width,repetition rate and cumulative number of spectrum)which had influence on spectral line.The experimental conditions were determined as follows.The ICCD delay was1μs,the laser energy was50mJ,the ICCD gate width was3.5μs,the repetition rate was1Hz and the cumulative number of spectrum was100times.Under the optimal experimental conditions,the results of the electron temperatures Te and electron densities Ne were11604K and5.155×10^16cm^-3,respectively.The local thermal equilibrium condition of the plasma was satisfied.The results are useful for the analysis and detection of elements in soil.