激光能量及延迟时间对土壤中Cr等离子体特性的影响  

Influence of Laser Energy and Delay Time on Characteristic of Laser-Induced Chromium Plasmas in Soil

作　　者：陈添兵[1] 姚明印[1] 刘木华[1] 雷泽剑[1] 彭秋梅[1] 徐媛[1] 张旭[1] 

机构地区：[1]江西农业大学生物光电及应用实验室,江西南昌330045

出　　处：《应用激光》2011年第6期478-482,共5页Applied Laser

基　　金：新世纪优秀人才计划资助项目(项目编号:NCET-09-0168);江西省科技支撑计划资助项目(项目编号:2010BSB08901)

摘　　要：采用激光诱导击穿光谱(LIBS)技术对土壤样品中的Cr元素进行了分析,通过改变激光器能量及延迟时间,观测Cr等离子体信号强度的变化关系。实验结果表明,谱线强度随着激光能量的增大而增加,其信背比是先增大后减小,当激光能量为110 mJ时信背比最好;改变延迟时间时信背比随延迟时间的增大呈现先增后减的变化规律,谱线强度随延迟时间的增大而减小,最佳延时时间为0.84μs。根据谱线强度与元素浓度的关系,建立了定标曲线,曲线拟合度为0.988,得出Cr元素的最低检测限约为25.22μg/g。通过对数据的计算分析可知,选择合适的激光能量及延迟时间可以减少强烈的高温辐射干扰,提高检测限,有利于实现土壤中激光诱导击穿光谱方法的重金属元素在线检测。The element Cr was analyzed in soil samples by laser induced breakdown spectroscopy（LIBS）.Influence of laser energy and delay time on measurement by LIBS was investigated.The experimental result showed that with the laser energy increased the intensity of the spectrum line increased and the signal to background ratio（SBR） first increased,then decreased,when the laser energy reached 110 mJ,SBR was optimal;when the delay time were changed,the SBR increases and then decreases,and the intensity of spectrum decreases with the increasing delay time.The optimal delay time is 0.84μs.The calibration curve was constituted according to the intensity and concentration of Cr,the correlative coefficient was 0.988,and the minimum detection limit of Cr is 25.22μg/g. Through the analysis of data show the influenced of radiation can be limited and also the detection of on-line can be improved by selected the appropriate laser energy and the delay time.

关 键 词：激光诱导击穿光谱 激光能量 延迟时间 信背比 定标曲线 

分 类 号：TN249[电子电信—物理电子学]