不同气体环境下激光诱导击穿光谱实验条件优化

激光诱导击穿光谱(LIBS)分析性能受实验条件的影响较大,为此重点研究了空气、Ar气和He气3种不同气体环境下,激光能量、采光延时和气压等实验参数对铁合金中Fe原子谱线特性的影响。结果表明,相同实验条件下,Ar气中激光等离子体的寿命最长且谱线强度最强;相较于空气与He气,Ar气中激光诱导击穿阈值最低,谱线强度随激光能量的增长更早达到饱和;分析谱线在低气压下有更小的线宽,有利于复杂LIBS谱图中谱线的识别;谱线强度随气压的变化规律与激光强度有关,当激光强度较大,谱线始终处于饱和状态时,谱线强度随气压的增大而增加,当激光强度较弱,谱线未处于饱和状态时,谱线强度随气压的增加先增加后减小。

The laser-induced breakdown spectroscopy experiment condition optimization under different ambient environments

The performance of laser-induced breakdown spectroscopy (LIBS) is greatly affected by the experimental conditions. The influence of the experimental parameters such as laser energy, delay time and ambient pressure on the spectral characteristics of Fe in ferroalloy was focused under different ambient environments of air, Ar and He. The experimental results showed that the laser plasma had the longest lifetime and the strongest spectral intensity in Ar. Compared with air and He, the threshold of laser induced breakdown in Ar was the lowest, and the intensity of spectral line reached saturation earlier with the increase of laser energy. The spectral lines had smaller linewidth at low pressure, which was conducive to the identification of spectral lines in complex LIBS spectra. The variation of spectral intensity with pressure was related to laser intensity. When the laser intensity was large and the spectral line was always saturated, the spectral line intensity increased with the increase of ambient pressure; when the laser intensity was weak and the spectral line was not saturated, the spectral intensity first increased and then decreased with the increase of ambient pressure.