NaCl对激光诱导土壤等离子体辐射的增强效应  

Enhancement effect of NaCl additive on laser-induced soil plasma radiation

作　　者：陈金忠[1] 宋广聚[1] 陈振玉[1] 孙江[1] 李旭[1] 

机构地区：[1]河北大学物理科学与技术学院,河北保定071002

出　　处：《强激光与粒子束》2012年第2期476-480,共5页High Power Laser and Particle Beams

基　　金：国家自然科学基金项目(10804025);河北省自然科学基金项目(A2006000951)

摘　　要：为了改善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土壤样品,由光栅光谱仪和光电检测系统记录等离子体发射光谱,研究了激光输出能量(100～500mJ)和NaCl样品添加剂(质量分数0%～20%)对等离子体辐射强度的影响。实验结果表明,在激光能量为200mJ的优化条件下,可以提高光谱强度和信噪比,而更高激光能量诱导的等离子体中光谱线自吸严重。当土壤样品中加入适量NaCl添加剂以后,能够进一步改善激光光谱质量。NaCl加入量为10%时,等离子体中元素Fe,Ba,Al和Ti的谱线强度比无添加剂时分别提高了37%,32%,32%和70%,光谱信噪比分别提高了33%,26%,16%和38%。而样品烧蚀量、电子温度和电子密度比无添加剂时分别提高了14%,9.6%和26%。To improve the quality of laser-induced breakdown spectroscopy, the nanosecond pulse laser generated by Nd： YAG laser was used to excite soil samples. The plasma spectrum was observed using a grating spectrometer and a photoelectric detection system. The influence of laser output energy ranging from 100 mJ to 500 mJ and NaC1 additive content ranging from 0 % to 20 % on the radiation intensity of plasma was studied. The experimental results show that both the line intensity and the signal- to-background ratio can be enhanced under the optimized condition that the laser energy is 200 mJ, and further increase of laser energy generates serious self-absorption effect in the laser-induced plasma. However, further improvement of spectrum quality was observed with adding proper amountof NaC1 additive into the soil sample. For instance, when the content of NaC1 additive is 10%, the spectral line intensities of elements Fe, Ba, A1 and Ti increase around 37%, 32%, 32%/00 and 70% than those without additive; the spectral signal-to-background ratios increase about 33%, 26%, 16% and 38%; while the ablation mass, electron temperature and electron density of plasmas go up 14%, 9.6% and 26%, respectively.

关 键 词：激光诱导等离子体 NaCl添加剂 烧蚀量 电子温度 电子密度 

分 类 号：O433.2[机械工程—光学工程]