Faraday rotation spectroscopy (FRS) employs the Faraday effect to detect Zeeman splitting in the presence of a magnetic field. In this article, we present system design and implementation of radical sensing in a photolysis reactor using FRS. High sensitivity (100 ppb) and time resolved in situ HO₂ detection is enabled with a digitally balanced acquisition scheme. Specific advantages of employing FRS for sensing in such dynamic environments are examined and rigorously compared to the more established conventional laser absorption spectroscopy (LAS). Experimental results show that FRS enables HO₂ detection when LAS is deficient, and FRS compares favorably in terms of precision when LAS is applicable. The immunity of FRS to spectral interferences such as absorption of hydrocarbons and other diamagnetic species absorption and optical fringing are highlighted in comparison to LAS.

中文翻译：

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法拉第旋转光谱法在光解反应器中时间分辨HO ₂检测

法拉第旋转光谱法（FRS）利用法拉第效应检测在磁场存在下的塞曼分裂。在本文中，我们介绍了使用FRS在光解反应器中进行自由基检测的系统设计和实现。利用数字平衡采集方案，可以实现高灵敏度（100 ppb）和时间分辨的原位HO ₂检测。与更成熟的常规激光吸收光谱法（LAS）相比，已对将FRS用于此类动态环境中的传感的特定优势进行了检查，并进行了严格的比较。实验结果表明，FRS可以激活HO ₂当LAS不足时进行检测，FRS在适用LAS时在精度方面具有可比性。与LAS相比，突出了FRS对光谱干扰（例如碳氢化合物的吸收以及其他抗磁性物质吸收和光学条纹）的抗扰性。