摘要
以土壤样品为靶,提出利用小型碳室对高能量激光诱导等离子体进行空间限制来提高等离子体发射光谱质量。采用高能量脉冲激光烧蚀土壤样品,利用组合式多功能光栅光谱仪和CCD探测器等组成的光谱分析系统记录光谱信息,研究了激光诱导等离子体在有或无碳室约束条件下辐射强度的变化;通过光谱学测量方法求得电子温度和电子密度,用以解释等离子体辐射增强的机理。实验结果显示,当利用小型碳室约束激光等离子体时,土壤样品元素Mn,K,Fe和Ti的光谱线强度比无碳室约束时分别提高了90.77%,101.71%,104.27%和60.77%;光谱信噪比分别提高了54.29%,55.30%,59.37%和38.80%;等离子体的电子温度和电子密度分别提高了1 684K和1.8×1016 cm-3。得到的结果表明,利用空间约束方法能够有效地提高激光诱导等离子体的发射光谱强度和信噪比,为利用激光诱导击穿光谱技术检测物质中低含量成分奠定了基础。
Abstract： By taking soil samples as targets, a small carbon chamber was used to perform the spatial confinement for high energy laser induced plasma to improve the quality of laser-induced breakdown spectroscopy. A high energy laser was used to ablate the soil samples, a spectral analysis system con- sisting of a modular multifunctional grating spectrometer and a CCD detector was adopted to record the spectral information, and the changes of the radiation intensities of laser-induced soil plasma with and without the small carbon chamber were studied. Then, the electron temperature and electron den- sity of the plasma were measured by the spectroscopic methods to explain the mechanism of irradiation enhancement of the plasma. Experimental results show when the laser plasma is confined by the small carbon chamber , the spectral line intensities of the sample elements Mn, K, Fe and Ti increase about 90.77%, 101.71%, 104.27% and 60.77% than that without the small carbon chamber, and spectral signal-to-noise ratio raises around 54.29%, 55.30%, 59.37% and 38.80%, while the electron temperature and electron density of the plasma enhance about 1 684 K These results demonstrate that the spectral intensities and signal plasma can be improved effectively by spatial confinement for the which is an effective means for detecting the low-content elements and 1.8× 1016 cm-3 , respectively. to-noise ratio of the laser-induced high energy laser induced plasma, in soil samples.
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2013年第8期1942-1948,共7页
Optics and Precision Engineering
基金
国家自然科学基金资助项目(No.10804025)
河北省自然科学基金资助项目(No.A2006000951)
关键词
激光诱导击穿光谱
等离子体发射光谱
碳室
光谱强度
信噪比
电子温度
电子密度
Laser-induced Breakdown Spectroscopy（LIBS）
plasma emission spectrum
carbon cham-ber
spectral intensity
signal-to-noise ratio
electron temperature
electron density
