NO气体紫外差分吸收截面的测量

Measurement of the Ultraviolet Differential Absorption Cross Section of Nitric Oxide

气体吸收截面的测量是影响差分吸收光谱技术（DOAS）测量精度的主要因素。为了得到吸收特征明显的NO气体吸收截面,采用分辨率为0.1 nm的高精度光谱仪、氘灯光源和自制的封闭式实验测量系统。将吸收截面分解为快变部分和慢变部分,并利用多项式拟合的方法对结果进行了修正。实验得到了NO气体在200~230 nm紫外波段的吸收截面。结果表明：相较于传统的测量方法,采用高分辨率的光谱仪和封闭式测量系统得到的吸收截面具有更好的吸收特性。利用多项式拟合的方法分离慢变部分可以提高测量精度。

As the main factor affecting the precision of the differential optical absorption spectrometry （DOAS） , the absorption cross section is measured by a spectrometer with the resolution 0. 1 nm, a deuterium lamp and a self -fabricated closed sample cell, and the measurement theory is studied. The absorption cross section is decomposed into fast and slowly varying parts, and the results are modified by the method of polynomial fitting. The absorption cross section of NO gas in 200 -230nm ultraviolet band is obtained. The results indicate that the absorption cross section obtained by the high resolution spectrometer and closed measurement system has better absorption characteristics compared with the traditional measurement method. Measurement accuracy can be improved by using polynomial fitting method.