光学调制相消法用于高灵敏气相同位素丰度测量的技术研究

项目名称： 光学调制相消法用于高灵敏气相同位素丰度测量的技术研究

项目编号： No.61275213

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 无线电电子学、电信技术

项目作者： 董磊

作者单位： 山西大学

项目金额： 86万元

中文摘要： 气相同位素丰度分析在多个学科中都有着重要应用，但目前质谱仪和传统的分离谱线测量法并不能够满足人们日益增长的对仪器的便携性和对测量的高精度的需要。项目申请者提出的光学调制相消法是一种新型高灵敏光谱分析法，能够用于对同位素丰度的测量。这种方法以零背景技术QEPAS作为载体，使两束对应不同同位素吸收线的激光光束以相同比率共同通过参考池和分析池，通过设置两个激光调制信号反相并平衡参考池输出信号为零，从而使分析池输出信号直接为所求的千分差值。在此方法中，由于测量的扰动是通过相对误差而不是绝对误差传递给被测结果，因此其理论预测精度能够达到0.006‰，高出分离谱线测量法几个数量级。然而，前期实验预研表明这种新技术仍然有QTF对儿使用寿命短、测量结果受无用直流分量干扰、探测功率增大噪声背景升高等关键性问题亟待解决。本项目拟通过理论和实验分析，提出具体的解决方案，为气相同位素分析提供一种新的探测手段。

中文关键词： 光学调制相消法；石英增强光声光谱；石英晶振；同位素丰度分析；

英文摘要： Isotopic abundance analysis has wide applications in multiple disciplines. However, current mass-spectrometer (MS) and traditional separate line measurement approach can not meet all requirements of portability and high-accuracy. Modulation cancellation method (MOCAM) applicant proposed is a novel high sensitive technique for spectroscopic analysis which can be used to measure isotope composition. The basic concept of MOCAM requires that the respective powers and modulation phases of the two lasers resonant with two selected absorption lines are adjusted in such a way that the signal detected from the reference sample is zero. In this case, the signal from the analyzed sample is directly proportional to the deviation of the absorption line strength ratio from the reference ratio.Since the fluctuations during meaurements are transferred to results as its relative error, but not the absolute error, the advantage of this method over the traditional separate line measurement approach is that the accuracy is expected to be 0.006‰ that is several orders of magnitude higher with the simple experimanental setup. However, the preliminary result of the experiment shows that there are some key problems need to be solved, such as the short life of QTF pair, the disturbance of DC offset on signal, higher noise level with hig

英文关键词： Modulation cancellation method；Quartz-enhanced photoacoustic spectroscopy；Quartz tunign fork；Isotopic composition measurements；