KCl添加剂对激光诱导土壤等离子体辐射强度的影响

Effect of KCl Additive on Laser-Induced Soil Plasma Radiation

为了提高激光诱导击穿光谱技术对低含量物质成分的检测能力,实验研究了KCl添加剂对土壤样品发射光谱的增强效应。利用高能量钕玻璃脉冲激光器烧蚀样品,由组合式多功能光栅光谱仪和CCD数据采集处理系统记录等离子体光谱,并通过测量光谱线的强度和Stark展宽分别计算了等离子体的电子温度和电子密度。实验结果证明,随着KCl加入量的增加,激光等离子体的光谱强度、信背比、电子温度和电子密度均呈现出先增大而后减小的规律。当KCl加入量为15%时,等离子体辐射最强,元素Mn,Fe,和Ti的谱线强度分别比无添加剂时提高了2.23,1.13和2.04倍,信背比分别提高了1.33,0.89和0.94倍;而等离子体的温度和电子密度比无添加剂时分别提高了14%和38%。

In order to improve laser-induced breakdown spectroscopy for low-level elements testing capability,the enhancement effects of KCl additive on the emission spectra of soil samples were studied.The laser spectrum analytical system is composed of a high-energy neodymium glass laser ablating samples,a multifunctional and automatic scanning spectrometer,and a CCD data acquisition system recording plasma spectra.The electron temperature and electron density of plasmas were calculated by measuring spectral line intensity and stark broadening respectively.The experimental results showed that with the increase in the KCl additive,the spectral intensity,signal-to-background ratio,the electron temperature and the electron density all went up firstly and then down.When 15% KCl was added,the radiation intensity of plasma reached the maximum value,the spectral lines intensity of element Mn,Fe,and Ti increased by 2.23,1.13 and 2.04 than that without additive respectively,the spectral signal-to-background ratio increased by 1.33,0.89 and 0.94 times respectively; while the electron temperature and electron density of plasmas were heightened by 14% and 38% respectively.