论文部分内容阅读
激光诱导击穿样品产生的等离子体寿命通常在微秒量级,对其时间演化过程进行了解有利于优化信号采集。定标曲线是定量分析的基础,并且与测量灵敏度和准确度密切相关。采用聚焦的脉冲激光束击穿样品形成等离子体,其发射光谱由中阶梯光栅光谱仪分光,并由增强型电荷耦合器件(ICCD)进行光电探测采集。为了实现对金属元素的激光诱导击穿光谱(LIBS)测量,在石墨中分别加入Ca,Al,Na,K等元素制作成片状实验样品,利用实验装置进行了系统的激光击穿光谱探测研究。应用ICCD100ns光学门宽的时间分辨率,通过实验得到了等离子体的时间演化特性曲线,分析了激光击穿固体样品后各待测元素的演化过程。根据含有不同浓度的同种元素样品的LIBS实验结果,归纳出各元素浓度与谱线强度的定标曲线,且大多数定标曲线的线性拟合相关度较高。同一元素不同波长的谱线,其定标曲线的斜率不同,对其差异进行了分析。
Laser-induced breakdown of plasma samples generated by the sample is usually in the order of microseconds, understanding of its evolution of time is conducive to optimizing signal acquisition. Calibration curves are the basis for quantitative analysis and are closely related to measurement sensitivity and accuracy. A focused pulsed laser beam was used to break down the sample to form a plasma. The emission spectrum was spectrally resolved by a mid-scale grating spectrometer and photodetected by an enhanced charge-coupled device (ICCD). In order to realize laser-induced breakdown spectroscopy (LIBS) measurement of metal elements, Ca, Al, Na, K and other elements were added into graphite respectively to make sheet-like experimental samples, and laser breakdown spectroscopy . Using the time resolution of ICCD100ns optical gate width, the time evolution curve of the plasma was obtained through experiments. The evolution of each element under test after the laser penetrated the solid sample was analyzed. According to the results of LIBS with different concentrations of the same elemental samples, the calibration curve of each element concentration and spectral line strength was summarized, and the linear fitting correlation of most calibration curves was high. The same element of different wavelengths of spectral lines, the slope of the calibration curve is different, the differences were analyzed.