【摘要】 免定标(CF)方法是一种面向激光诱导击穿光谱(LIBS)的定量分析方法,可在无定标曲线的情况下直接完成探测元素的含量计算，但传统CF-LIBS的实际定量结果往往与真实值存在一定差距。为了提高CF-LIBS定量分析结果的精度,本文使用三种不同质量比的标准铜锌合金靶进行CF-LIBS定量分析计算，通过“准光学薄态逼近”和“谱线自吸收校正”,成功实现了合金靶中Zn/Cu质量比的准确定量。在具体实施过程中,首先通过调节“激光能量”和“探测延时”逼近元素双线比的理论强度值,以此寻获等离子体的“准光学薄”状态。在此基础上,根据元素谱线计算相应的自吸收系数,依据该系数进行LIBS光谱强度的修正,以此完成LIBS谱线的自吸收校正。两部分工作的有效结合,显著提升了CF-LIBS定量的分析精度,结果显示测算的铜锌元素质量比与实际含量非常吻合,三种标准铜锌合金靶的定量误差均小于3.5%,证明了本文所提出方法的有效性和合理性,未来有望在其他领域获得应用验证。更多还原

【Abstract】 The calibration-free(CF) method is a quantification approach for laser-induced breakdown spectroscopy(LIBS) that enables the content determination of detected elements without a calibration curve. However, the actual quantitative results of traditional CF-LIBS often exhibit discrepancies with respect to the real values. In order to improve the accuracy of CF-LIBS quantitative analysis results, three standard Cu-Zn alloy targets with different mass ratios were used for the calculation of CF-LIBS quantitative analysis, and accurate quantification of the Zn/Cu quality ratio in the alloys was successfully achieved through utilization of "quasi-optically thin state" and "self-absorption correction". In the implementation, we firstly approached the theoretical intensity ratio of copper lines(I521.8 nm/I515.3nm) by adjusting laser energies and detection delays, so as to find the "quasi-optically thin state" of the plasma. And then, under such a plasma state, the spectral intensity was well corrected by the selfabsorption via referencing the corresponding coefficient. Based on the proposed method, the Cu/Zn quality ratio was accurately determined using CF-LIBS, exhibiting excellent agreement with the actual content. The quantitative biases of the three standard copper-zinc alloy targets were observed all less than 3.5%, indicating high precision of measurements. It proves that the developed method is effective in improving alloys quantitation of LIBS, and more applications are expected in other fields in the future.更多还原